Case- hardening steels - SCHMOLZ - BICKENBACH: Sales

EDELSTAHL WITTEN-KREFELD GMBH

CARBODUR CARBODUR

Engineering steels

CARBODUR CARBODUR

CARBODUR CARBODUR Case-hardening steels

Contents Page 4 – 7

Carbodur – The material

Page 8 – 9

Energy industry

Page 10 – 11

Transport

Page 12 – 13

General mechanical engineering

Page 14 – 15

Steel portraits

Page 16 – 17

Steel production

Page 18 – 19

Steel processing

Material data Page 20 – 31

Material Data Sheets (Please note the text on the flap of the rear cover, which contains information on the Material Data Sheets)

Technical information Page 32 – 36

Hardenability

Page 37 – 39

Machining and heat treatment

Page 40 – 43

Case-hardening treatment

Page 44

Overview of grades and chemical composition

Page 45

Melt analysis/International standards

Page 46

Forms supplied

Page 47

Hardness comparison table

Page 48

Temperature Comparison

Page 50

List of photos 3

CARBODUR

Hard case, tough core – gets to grips

How long a component stands up to demands, and how reliably it withstands peak stresses, de-

pends on the material the component is made of. In the final analy-

In terms of non-metallic inclu-

sis, the load-bearing capacity of a

sions, the purity of these steels is

small part determines the cost-

higher than that of normal quality

efficiency of large machines or

steels. They also respond more

installations.

uniformly to heat treatment.

The more carefully the material is

Through precise adjustment of

tailored to the function of the re-

the chemical composition and the

spective components, the more

use of special production and test

efficient the entire system is.

conditions, we are in a position to

Edelstahl Witten-Krefeld is the

supply you with steel grades

specialist for producing high-

manufactured with a wide variety

grade steels with highly specific,

of processing and service proper-

precisely defined properties.

ties. Following carburising and

The group of case-hardening

hardening of the surface, case-

steels marketed under the brand

hardening steels display great

name Carbodur is evidence of the

hardness and wear resistance in

leading international position of

the region of the surface layer,

Edelstahl Witten-Krefeld in the

while the strength and toughness

field of high-strength, high-grade

of the base material are retained

steels.

in the core.

The case-hardening steels presented in this brochure are unalloyed and alloyed special engineering steels with relatively low carbon contents of roughly 0.10 to 0.25%.

4

Carbodur with wear problems Consequently, case-hardening steels or case-hardened components are indispensable wherever high wear resistance, high fatigue strength and low notch sensitivity are required. The choice of a steel grade is governed by the intended application, the types of stress involved and the dimensions of the parts or the geometry of the components in question. Technical and economic aspects are likewise of decisive importance. Our materials specialists are available for consulations concerning the optimum choice and most expedient use of the various casehardening steel grades.

Carbodur –

unbeatable for

hardness

and

durability 5

Maximum purity

nickel-chrome-molybdenum case-

High fatigue strength

The strength and toughness of

hardening steels and chrome-

Inherent compression stresses

the base material are determined

nickel-molybdenum case-harden-

arise in the surface layer when

by its chemical composition and

ing steels.

case-hardening a component.

the heat treatment it undergoes.

The great hardness and the

These stresses counteract the

Consequently, the required prop-

fatigue strength of the surface

external stresses, which are

erties of the steel are already spe-

layer are achieved by the case-

cifically targeted when first melt-

hardening treatment, i.e. by car-

ing the steel. The facilities in

burising, hardening and temper-

Witten and Krefeld permit a highly

ing (or stress relieving). If, for

accurate and reliably repeatable

example, high strength is required

chemical composition. An ex-

in combination with high tough-

tremely high degree of purity is

ness of the core, the alloying ele-

achieved by the spot-on melt

ments must be matched in such a

analysis, secondary metallurgical

way that through-hardening is

treatment and vertical continuous

guaranteed at a given cross-sec-

casting, or alternatively by remelt-

tion and with the given heat treat-

ing. Non-metallic inclusions are

ment. This steel-specific through-

virtually ruled out.

hardening is offered by Carbodur,

The high degre of macroscopic

even at large cross-sections.

and microscopic purity, the

We are in a position to offer you

homogeneity of the microstruc-

case-hardening steels manufac-

ture and the fine-grain stability of

tured specifically with the hard-

our Carbodur grades cannot be

ness you require. Make use of

beaten by any other manufacturer

this opportunity - talk to our

of high-grade steels.

materials specialists!

Controlled hardenability

High fine-grain stability

The selection of appropriate al-

The targeted adjustment of the

loying elements permits targeted

aluminium and nitrogen contents

control of the hardenability of the

of our Carbodur steels results in

base material and the hardenabil-

outstanding fine-grain stability.

mostly of a tensile nature, and

ity of the carburised surface layer.

Thanks to this high fine-grain sta-

thus increase the fatigue strength.

In addition to unalloyed case-

bility, our steels are particularly

In addition to their extraordinary

hardening steels, we also offer

suitable for the direct hardening

wear resistance, components

the following alloyed versions:

of components, a process carried

made of Carbodur steels are thus

manganese-chrome case-harden-

out at high temperatures. Coarse-

characterised by very high

ing steels, molybdenum-chrome

grain or mixed-grain steel would

strength under dynamic loads

case-hardening steels, nickel-

result in non-uniform distortion

once they have been hardened.

chrome case-hardening steels,

and reduced toughness.

However, case-hardened compo-

6

Spot-on right

efficiency of series production is already defined when ordering the steel. The machinability of casehardening steels is influenced by the microstructure, the strength and the non-metallic inclusions

– Carbodur has just the chemstry for you

(sulphides, oxides) that may be present. The machinability of the steel can be further optimised by increasing the amount of sulphidic inclusions, by calcium treatment and by appropriate heat treatment, i.e. by specifically adjusting the microstructure.

Made-to-measure heat treatment Depending on the intended application and processing, we can supply you with Carbodur steel grades in a wide variety of treated conditions, e.g. with reduced hardness, maximum hardness or a specific hardness range, treated for ferrite-pearlite structure or for spherical carbides. Detailed technical information on nents also have to demonstrate

Good machinability

forms supplied and machining

the highest possible ductility

The larger the quantity of compo-

can be found from Page 32

when exposed to high dynamic

nents to be manufactured, the

onwards.

stresses, in order to avoid brittle

more important the demand for

fractures. As the impact strength

good machinability of the materi-

of the component decreases with

al. This means that the economic

increasing case-hardening depth, the latter must not be too great.

7

More staying with Carbodur

The world of Carbodur steels is the world of drive systems. Their strengths are in demand wherever power is transmitted. The individual components of the mighty transmission mechanisms used in hydroelectric power stations, wind turbine generators or in the offshore industry not only have to withstand enormous pressures per unit of area, they also have to run constantly and untiringly. This calls for wear resistance and fatigue strength. Precision gear wheels made of Carbodur in the propeller drives of drilling rigs and turbine gears of power stations reliably

Here, the emphasis is not so much

withstand the stresses and, thanks

on resistance to impact and shock

to their wear resistance, reliably

loads as on hardness and core

guarantee the dimensional stability

strength. Our chrome/nickel or

of the components. Safety takes

chrome/nickel/molybdenum-

top priority in the mining sector.

alloyed Carbodur grades, for ex-

The underground extraction equip-

ample, offer the best prerequisites

ment essentially works non-stop

for meeting the stringent require-

without a break. Malfunctions

ments. Our Carbodur 17 CrNi 6-6

brought about by the failure of

and Carbodur 18 Cr NiMo 7-6

transmission components not only

grades, for instance, are particu-

mean expensive interruptions in

larly suitable for relatively large

production, but also increase the

cross-sections.

safety risk.

8

Energy industry

power – case-hardening steels

Carbodur – takes

more,

lasts

longer 9

Carbodur – the winner comes Just as there is a wide variety of

long periods, and must also be

demands on the components for

capable of absorbing sudden

different types of vehicle, we also

blows and shocks without losing

have a wide variety of options for

any teeth. The case-hardened

precisely adapting our Carbodur

parts have to display a combina-

steels to suit the prevaillign re-

tion of wear resistance and fatigue

quirements. The suitable material

strength in the surface layer and

for the components is selected

impact strength in the core zone.

with a view to safety, economic

Safety takes top priority in the

efficiency and a long service life,

passenger transport sector. Con-

or the ability to withstand extreme

sequently, the specific properties

stresses for short periods.

of Carbodur steels are particularly

The differential of a Formula 1 car,

advantageous for engines and

for example, only has to withstand

gearboxes in automotive engi-

stress for a relatively short time -

neering. They can be used, for

the duration of a race (at least!).

example, in piston pins, speed

On the other hand, it is exposed to

change gears, drive shafts, coun-

extreme stresses for short periods

tershafts, synchroniser bodies,

of time as a result of the enormous

ring gears, differential bevel gears,

torques transmitted. Carbodur

bevel pinions and differential side

steel can be specifically “tuned” to

gears.

cope with this task. In contrast, the gear wheels of a truck that works under the tough conditions of a building site have to take constant punishment over

10

Transport

when it to extreme stresses

Carbodur – hard and for the

for the

moment

duration 11

Carbodur case-hardening the prescription

Maximum precision on the one

hand, and maximum sturdiness on the other – two different requirements, but always one task for

good idea to use the same steel in

Carbodur. In terms of precision, a

heavy-duty transmissions, e.g. in

printing press is like a giant clock-

the mining industry or in an exca-

work: screen resolutions of as little

vator, if only because of the larger

as 0.01 mm are required in order

dimensions or the machines, or of

to produce the finest prints. The

the gear wheels and other compo-

numerous gear wheels of the indi-

nents. The drivelines of mining

vidual printing units have to be

machines and construction ma-

manufactured to very close toler-

chinery have to withstand gigantic

ances. Wear means play in the

stresses. A breakdown caused by

wheelwork and impairs the quality

a broken tooth, for instance, can

of the resultant prints. Therefore,

cause expensive production stop-

the gear wheels and the individual

pages. Edelstahl Witten-Krefeld

assemblies of high-quality printing

not only supplies you with the

presses have to be manufactured

optimum steel grade for large

using a steel grade that is already

cross-sections, or bar stock with

melted to have a specific chemical

large dimensions, but also acts as

composition catering to the re-

your extended workbench, as it

quirements, or that is produced for

were, by providing pre-machined

specific hardenability. The steel, or

parts, such as pre-drilled disks.

the individual components, must

Talk to our specialists about these

be strong at the core, while the

options.

surface layer must withstand any wear whatsoever. And it has to do so at very high speeds and for years on end. It would not be a

12

und

General mechanical engineering

steels – against bad teeth

Carbodur –

d auf

für den

Moment

Dauer

Prevention with

Carbodur –

better than

false teeth 13

• Carbodur C 15 E/Carbodur C 15 R Unalloyed case-hardening steel for components in mechanical and automotive engineering with low core strength, primarily for wear stresses, such as levers and shafts.

How would you like it – whole or Large cross-sections Carbodur – definitely not run-ofthe-mill, but specifically tailored to your needs. Each of the basic grades briefly outlined here can be heat treated at the factory to adapt it for optimum machining and/or the minimum possible distortion during case-hardening. Above all, we are also in a position to supply these steel grades in the form of bar stock with large cross-sections and also in various processed stages. For example: disks sawn from bars, either with

Pre-machined to taste

or without a drilled hole. Our pro-

Make use of our wide-ranging

duction capabilities also include

capabilities and let us act as your

parts individually forged to shape.

extended workbench. Talk to our

The range of processing options

specialists. They can work with

goes all the way to bright surfaces

you in devising an individual solu-

with close tolerances.

tion to meet your needs.

14

Steel portraits • Carbodur 15 NiCr 13

• Carbodur 17 Cr 3

NiCr-alloyed case-hardening steel for highly

Cr-alloyed case-hardening steel for compo-

• Carbodur 18 CrNiMo 7-6

stressed components in mechanical engi-

nents in mechanical and automotive engi-

CrNiMo-alloyed case-hardening steel for

neering with high demands on toughness

neering with low core strength, primarily for

heavy-duty and highly stressed transmis-

at low temperatures.

wear stressed, e.g. piston pins and cam-

sion components in mechanical engineer-

shafts

ing with high demands on toughness, e.g.

• Carbodur 17 CrNi 6-6

gear wheels, pinion gears and worm shafts

CrNi-alloyed case-hardening steel for high-

• Carbodur 20 NiMoCrS 6-5

ly stressed components in mechanical and

NiMoCr-alloyed case-hardening steel for

automotive engineering with high strength

highly stressed components in mechanical

and toughness at relatively large cross-

and automotive engineering with high strength

sections, such as bevel pinions, pinion

and toughness, e.g. bevel pinions, pinion

gears, shafts, pins and countershafts

gears, shafts, pins and countershafts

sliced?

• Carbodur 20 MnCr 5 • Carbodur 20 MnCrS 5 CrMn-alloyed case-hardening steel for components in mechanical and automotive engineering with relatively high core strength, e.g. gear wheels, ring gears, main shafts and countershafts • Carbodur 20 MoCr 4 • Carbodur 20 MoCrS 4 MoCr-alloyed case-hardening steels for components in mechanical and automotive engineering with relatively high core strength, e.g. gear wheels, ring gears, main shafts and countershafts • Carbodur 20 NiCrMo 2-2 • Carbodur 16 MnCr 5

• Carbodur 18 CrNi 8

• Carbodur 20 NiCrMoS 2-2

• Carbodur 16 MnCrS 5

CrNi-alloyed case-hardening steel for high-

NiCrMo-alloyed case-hardening steel for

CrMn-alloyed case-hardening steel for

ly stressed components in mechanical and

components in mechanical and automotive

components in mechanical and automotive

automotive engineering with very high

engineering with relatively high core strength,

engineering with relatively high core

strength and toughness at relatively large

e.g. gear wheels, spiders and ball cages

strength, e.g. relatively large piston pins,

cross-sections, such as bevel pinions, pin-

• Carbodur 22 CrMoS 3-5

camshafts and gear wheels

ion gears, shafts, pins and countershafts

CrMo-alloyed case-hardening steel for components in mechanical and automotive engineering with relatively high core strength,

Carbodur –

metallurgical

e.g. gear wheels, ring gears, shafts and spiders

delicacies à la carte 15

We make our own recipes

Our own steel production in our

able in Krefeld for the production

modern steelworks in Witten is

of case-hardening steels involving

the basis for the purity and homo-

particularly stringent demands in

geneity of our case-hardening

terms of homogeneity, toughness

steels. Precisely defined proper-

and purity.

ties are achieved by means of exact alloying and process

Electroslag remelting process

specifications for smelting, shap-

In the electroslag remelting pro-

ing and heat treatment. The steels

cess (ESR), which works with al-

are smelted in a 130 t electric arc

ternating current, a cast or forged,

furnace.

self-consuming electrode is im-

The metallurgical precision work

mersed in a bath of molten slag,

is performed in a downstream

which serves as an electrical resis-

ladle furnace of the same size.

tor.

Depending on the steel grade and

The material to be remelted drips

the dimensions of the end prod-

from the end of the electrode

uct, the steel melted in this way is

through the slag and forms the

cast in ingots or continuous cast

new ingot in a water-cooled

blooms. Over 50 different mould

mould below. The heat dissipa-

formats are available for ingot

tion leads to directional solidifica-

casting, ranging from 600 kg to

tion in the direction of the longitu-

160 t.

dinal ingot axis.

The continuous cast blooms are

The remelting slag fulfils several

new ingot. In addition, the slag

manufactured in two strands on a

functions in this process. On the

has a high capacity for absorbing

vertical continuous casting ma-

one hand, it develops the neces-

non-metallic inclusions, which

chine in a 475 x 340 mm format.

sary process heat, while at the

means that the remelted material

A remelting steelworks with two

same time supporting chemical

is free of coarse inclusions. The

electroslag remelting (ESR) fur-

reactions, such as desulphurisa-

improvement in the microscopic

naces and two vacuum arc re-

tion, and acting as an anti-

purity is attributable to desulphur-

melting (VAR) furnaces is avail-

oxidant for the melting bath of the

isation and the resultant high

Remelting facilities

ESR

16

VAR

Ladle furnace

Scrap

130-t-electric arc furnace

Main production routes

Ladle degassing station (VD/VOD)

EDELSTAHL WITTEN-KREFELD GMBH THYSSEN KRUPP STAHL AG

Steel production

steel, using reliable and the best ingredients Blooming-slabbing mill

ot casting

Products Machining

Long forging machines

LSX 55 33 MN press

Finishing departments, forging shops

Heat treatment facilities

Peeling machines Finishing departments, rolling mills As-rolled

• Open-die forgings as-forged or machined • Forged semis

As-forged

LSX 25

• As-cast ingots As-continuously cast bloom material

• Forged round billets for tubemaking as-forged or peeled • Forged bar steel as-forged or machined • Machined tool steel forged or rolled • Rolled semis • Rolled tube rounds as-rolled or peeled

ontinuous bloom er, 475 x 340 mm, 2 strands

Untreated Blooming/billet/large-size bar rolling mill

• Rolled bar steel as-rolled or machined • Universal plate and flats • Special products

degree of sulphidic purity, and also to a reduction in the size and quantity of oxidic inclusions.

Carbodur –

technological

precision from the start

17

Carbodur tailored to suit Vacuum arc remelting process

lowest possible sulphur content

The vacuum arc remelting (VAR)

has to be set prior to remelting, in

process works with cast or

order also to meet the most strin-

forged, self-consuming elec-

gent demands on the degree of

trodes in a vacuum.

sulphidic purity. Moreover, this

Using an electric arc in a vacuum,

process guarantees the lowest

a melting bath is generated in a

possible quantities of dissolved

copper crucible, which acts as

gases in the steel and a minimum

the opposite pole to the remelting

of segregation.

electrode and is connected to a DC voltage source via current

Steel processing

contacts.

The blooming mill in Witten pro-

A new ingot is formed from the

duces semi-finished products,

liquefied electrode material drop

steel bars and wide flats. Two

by drop in a continuous process.

modern finishing lines for check-

In the VAR process, refinement of

ing the inner and outer surface

the steel is brought about by the

condition, as well as the dimen-

reaction of the oxygen dissolved

sions and identity, are available

in the steel with the carbon in the

for rolled and forged products

molten material under the effect

and steel bars. The forge is

of the vacuum. This results in the

equipped with a 33 MN press, a

best possible degree of micro-

GFM LSX 55 horizontal long forg-

scopic oxidic purity and freedom

ing machine and a GFM LSX 25

from macroscopic inclusions. As

long forging machine.

no desulphurisation takes place during this remelting process, the

18

Steel processing

– Steels precisely your applications

We

work ahead for your

benefit

19

CARBODUR® C 15 E / C 15 R Material No. Code

Material No.

Designation

Material No.

Designation

1.1141

C15E

1.1140

C15R

Chemical composition

C

Typical analysis in %

C 15 E 0.12 – 0.18 C 15 R 0.12 – 0.18

Hardness in various treatment conditions

Treated for shearing S HB

Si

Mn

P

S

≤0.40 ≤0.40

0.30 – 0.60 0.30 – 0.60

≤0.035 ≤0.035

≤0.035 0.020–0.040

Treated for strength TH HB

Soft-annealed A

1)

HB

Annealed to spherical carbides AC HB

max. 143

max. 135

Treated for ferritepearlite structure FP HB

Heat treatments Type of treatment

Treatment temperature

Case-hardening Carburising 2)

880 – 980 °C

Direct hardening Core refining Case refining Tempering (stress-relieving) 5)

880 880 780 150

3)

See flap for footnotes

Hardenability in the end-quench test

– – – –

980 920 820 200

Cooling Water (oil), Hot bath 160 – 250 °C, case-hardening box, air

°C °C °C °C

Water (oil), hot bath 160 – 250 °C Water (oil), hot bath 160 – 250 °C Water (oil), hot bath 160 – 250 °C Air

Distance from the quenched end in mm 1

2

3

4

5

6

7

8

45 39

42 35

35 31

33 27

32 25

28 22

26 20

24 –

Hardness in HRC

H max. min.

Hardenability diagram 55 50 45

Hardness HRC Härte ininHRC

40 35 30 25 20 15 0

5

10

15

20

25

30

35

40

Distance from quenched endininmm mm Abstand von der abgeschreckten Stirnfläche

20

45

4) 4) 4)

4)

CARBODUR® 15 NiCr 13 Material No. Code

Chemical composition Typical analysis in %

Material No.

Designation

1.5752

15NiCr13

C

Si

Mn

P

S

0.14– 0.20

≤ 0.40

0.40 – 0.70

≤0.035

≤0.035



* For diameters up to 150 mm ** For diameters up to 60 mm

Cr

Ni

0.60 – 0.90 3.60– 3.50

Treated for strength TH* HB

Soft-annealed A

179 – 229

max. 255

HB


Treated for ferritepearlite structure FP** HB

max. 229

max. 180

166 – 217

Heat treatments


Type of treatment


Case-hardening Carburising 2) Direct hardening 3) Core refining Case refining Tempering (stress-relieving) 5)

880 – 980 °C


880 840 780 150

– – – –

980 880 820 200

Cooling Oil (water), hot bath 160 – 250 °C, Salt bath (580 – 650 °C), case-hardening box, air

°C °C °C °C

Oil, hot bath 160 – 250 °C Oil, hot bath 160 – 250 °C Oil, hot bath 160 – 250 °C Air

4)

4) 4) 4)

Distance from the quenched end in mm 1.5

3

5

7

9

11

13

15

20

25

30

35

40

H max. min.

48 41

48 41

48 41

47 40

45 38

44 36

42 33

41 30

38 24

35 22

34 22

34 21

33 21

HH max. min.

48 43

48 43

48 43

47 42

45 40

44 39

42 36

41 34

38 29

35 26

34 26

34 25

33 25

HL max. min.

46 41

46 41

46 41

45 40

43 38

41 36

38 33

37 30

33 24

31 22

30 22

30 21

29 21

Hardness in HRC

Hardenability diagram

Time-temperature-transformation diagram for continuous cooling 1200

55

1100

50

1000

HH grade HH-Sorte

45

Überschneidung Overlap of HH+HL-Sorte

900

HL-Sorte HL grade

800

Temperature ino°C Temperatur in C

40 Härte ininHRC Hardness HRC

AC3

HH + HL grade

35 30

AC1

700 A 600

400

70

5

500

F 75

75 75 15 25

75

P

45

B

Ms

30

50

90 95 90

50

20

300

15

15

M

25

8

200 100

20

Hardness values Härtewerte

HV 10

360 352 328 313 282 277 261 245

231

228

227

192 169

0 100 Zeit Timeinins s

15 0

5

10

15

20

25

30

35

40

Abstand von der abgeschreckten Stirnfläche Distance from quenched endininmm mm

45

101

102 100 Zeit ininmin Time min

103

104

101

102 100 Zeit Timeininh h

105

106

103 101

104 102

21

CARBODUR® 16 MnCr 5 / 16 MnCrS 5 Material No. Code

Material No.

Designation

Material No.

Designation

1.7131

16MnCr5

1.7139

16MnCrS5


C


16 MnCr 5 0.14– 0.19 16 MnCrS 5 0.14– 0.19




Si

Mn

P

S

≤0.40 ≤0.40

1.10 – 1.30 1.10 – 1.30

≤0.035 ≤0.035

≤0.035 0.80 – 1.10 0.020–0.040 0.80 – 1.10


Soft-annealed A

156 – 207

1)

Cr

HB



max. 207

max. 165

140 – 187




880 – 980 °C


880 860 780 150

3)



– – – –

980 900 820 200

Cooling Oil (water), hot bath 160 – 250 °C, Salt bath (580 – 680 °C), case-hardening box, air Oil (water), hot bath 160 – 250 °C 4) Oil (water), hot bath 160 – 250 °C 4) Oil (water), hot bath 160 – 250 °C 4) Air

°C °C °C °C

4)


3

5

7

9

11

13

15

20

25

30

35

40

H max. min.

47 39

46 36

44 31

41 28

39 24

37 21

35 –

33 –

31 –

30 –

29 –

28 –

27 –

HH max. min.

47 42

46 39

44 35

41 32

39 29

37 26

35 24

33 22

31 20

30 –

29 –

28 –

27 –

HL max. min.

44 39

43 36

40 31

37 28

34 24

32 21

30 –

28 –

26 –

25 –

24 –

23 –

22 –

Hardness in HRC


Time-temperature-transformation diagram for continuous cooling

55

1200 1100

50

1000

HH-Sorte HH grade 45


900

HL-Sorte HL grade

800

Temperature Temperatur in in o°C C

40 Hardness HRC Härte ininHRC

AC3

HH + HL grade

35 30

700

F

3

P

40 5

A

B

10 20

500 MS

400

97

100

81 80

M

85

77

300

25

100

50

37

30

15 93

Hardness values Härtewerte 394

317

15 0

5

10

15

20

25

30

35

40


45

100

182 170 156

278 251 243 221 207 199 187

HV 10 0

22

65

35

200

20

AC1

65 35

60

30 40 50 50 60

20

3 10 15

600

188

101

102

103

104

105

106

Zeit inins s Time 100

101

102

103

104

Zeit in min Time in min 100 Zeit ininh h Time

101

102

CARBODUR® 17 Cr 3 Material No. Code


Material No.

Designation

1.7016

17Cr3

C

Si

Mn

P

S

Cr

0.14– 0.20

≤0.40

0.60 – 0.90

≤0.035

≤0.035

0.70 – 1.00



Treated for strength TH HB

Soft-annealed A

1)

HB


max. 174

max. 155

Treated for ferritepearlite structure FP HB

Heat treatments


Type of treatment



880 – 980 °C


880 860 780 150

– – – –

980 900 820 200

Cooling Wasser (Öl), Hot bath 160 – 250 °C, case-hardening box, air

°C °C °C °C

Water (oil), hot bath 160 – 250 °C Water (oil), hot bath 160 – 250 °C Water (oil), hot bath 160 – 250 °C Air

4)

4) 4) 4)


3

5

7

9

11

13

15

20

25

H max. min.

47 39

44 35

40 25

33 20

29 –

27 –

25 –

24 –

23 –

21 –

HH max. min.

47 42

44 38

40 30

33 24

29 20

27 –

25 –

24 –

23 –

21 –

HL max. min.

44 39

41 35

35 25

29 20

25 –

23 –

21 –

20 –

– –

– –

Hardness in HRC



55

1200 1100

50

1000

HH grade HH-Sorte

45


900

HL grade HL-Sorte

800


HH + HL grade


40 35 30

700

F

600 MS 500 400

AC3

A

1

5

15

35

AC1

75 25

70 75 72 20 25 15 1 3

30 67

P

B 85

M

65 20 15

5

3

300

25

200 100

20

446

Hardness Härtewerte values

HV 10 0 100 Zeit Timeinins s

15 0

5

10

15

20

25

30

35

40

Abstand von der abgeschreckten Stirnfläche Distance from quenched endin in mm mm

45

439

181 368

101

297 236 206

160 151

141

102 100 Zeit ininmin Time min

103 101

104 102 100 Zeit Timeininh h

105

106

103 101

104 102

23

CARBODUR® 17 CrNi 6-6 Material No. Code


Material No.

Designation

1.5918

17CrNi6-6

C

Si

Mn

P

S

0.14– 0.20

≤0.40

0.50 – 0.90

≤0.035

≤0.035




max. 255

Cr

Ni

1.40 – 1.70 1.40 – 1.70


Soft-annealed A

175 – 229

HB



max. 229

max. 178

156– 207

Heat treatments


Type of treatment


Case-hardening Carburising 2) Intermediate annealing Core refining Case refining Tempering (stress-relieving) 5)

880 – 980 °C


630 830 780 150

– – – –

650 870 820 200


°C °C °C °C

Air, furnace Oil (water), hot bath 160 – 250 °C Oil (water), hot bath 160 – 250 °C Air

4)

4) 4)


3

5

7

9

11

13

15

20

25

30

35

40

H max. min.

47 39

47 38

46 36

45 35

43 32

42 30

41 28

39 26

37 24

35 22

34 21

34 20

33 20

HH max. min.

47 42

47 41

46 39

45 38

43 36

42 34

41 32

39 30

37 28

35 26

34 25

34 25

33 24

HL max. min.

44 39

44 38

43 36

42 35

39 32

38 30

37 28

35 26

33 24

31 22

30 21

29 20

29 20

Hardness in HRC



55

1200 1100

50

1000



900

HL-Sorte HL grade

800

Temperature in o°C Temperatur in C


AC3

HH + HL grade

35 30

AC1

700

F

600

3

15

5 10

60 65 40 55 10 35

30

A 500

70 75 25 35 30

P

MS

100

400

100

100

100

B

100 97

95

100

M

90 85

300

70

60 35 5

25

200 Hardness values Härtewerte

100

20

409

HV 10 0

15 0

5

10

15

20

25

30

35

40


24

45

100 Zeit inins s Time

357

101

270

297 318

394

276

102 100

175 157

222

262 266

103 101

154

203 161 154

242

104 102

105

106

103

104

Zeit ininmin Time min 100 Zeit ininhh Time

101

102

CARBODUR® 18 CrNi 8 Material No. Code

Material No.

Designation

1.5920

18CrNi8


C


Si

Mn

0.15– 0.20 0.15–0.40 0.40 – 0.60




P

S

Cr

≤0.035

≤0.035

Ni

1.80 – 2.10 1.80 – 2.10


Soft-annealed A

199 – 229

max. 255

HB



max. 225

max. 180

158– 205






900 – 950 630 – 650 840 – 870 800 – 830 170 – 210

Cooling

°C °C °C °C °C

Oil (water), hot bath 160 – 250 °C, Salt bath (580 – 650 °C), case-hardening box, air Air, furnace Oil (water), hot bath 160 – 250 °C Oil (water), hot bath 160 – 250 °C Air

4)

4) 4)


3

5

7

9

11

13

15

20

25

30

35

40

H max. min.

49 41

49 41

49 40

49 39

49 39

49 38

49 37

49 36

48 35

47 35

47 34

46 34

46 33

HH max. min.

49 44

49 44

49 43

49 42

49 42

49 42

49 41

49 40

48 39

47 39

47 38

46 38

46 37

HL max. min.

46 41

46 41

46 40

46 39

46 39

45 38

45 37

45 36

44 35

43 35

43 34

42 34

42 33

Hardness in HRC



55

1200 1100

50

1000 900


45


40 35 30

AC1

700 600

5

HH + HL grade

400

MS

100

100

15 20

100

100 100 95

70

65

Härtewerte Hardness values

HV 10 0 100 Zeit inins s Time

15

90

B

200

20

10

P

500

HL grade HL-Sorte

5

10

300


0

F

30 30 5

A

M

HH grade HH-Sorte

25

AC3

800

25

30

35

40


45

429

425 417

101

425

390

102 100

363

342 333 312 312 312 268 249

103 101

104 102

105

106

103

104

Zeit ininmin Time min 100 Zeit ininh h Time

101

102

25

CARBODUR® 18 CrNiMo 7-6 Material No. Code

Material No.

Designation

1.6587

18CrNiMo7-6


C

Si

Mn

P

S

0.15– 0.21

≤0.40

0.50 – 0.90

≤0.035

≤0.035




Cr

Ni

1.50 – 1.80 1.40 – 1.70 0.25 – 0.35


Soft-annealed A

179 – 229

max. 255

Mo

HB



max. 229

max. 180

159– 207




880 – 980 °C

Intermediate annealing Core refining Case refining Tempering (stress-relieving) 5)



630 830 780 150

– – – –

650 870 820 200


°C °C °C °C

Air, furnace Oil (water), hot bath 160 – 250 °C Oil (water), hot bath 160 – 250 °C Air

4)

4) 4)


3

5

7

9

11

13

15

20

25

30

35

40

H max. min.

48 40

48 40

48 39

48 38

47 37

47 36

46 35

46 34

44 32

43 31

42 30

41 29

41 29

HH max. min.

48 43

48 43

48 42

48 41

47 40

47 40

46 39

46 38

44 36

43 35

42 34

41 33

41 33

HL max. min.

45 40

45 40

45 39

45 38

44 37

43 36

42 35

42 34

40 32

39 31

38 30

37 29

37 29

Hardness in HRC



55

1200 1100

50

1000 900


45


40 35 30 HH-Sorte HH grade

700

HL-Sorte HL grade

A

60

80 90 100 100 100 100 100

97

95

80

55

15

25

30

35

40


425

45


426

343

383 418

101

360

327 336

102 100

314

261

286

103 101

242

215

175

104 102

105

106

103

104


26

5


100

15 20

P

B

400 MS

HV 10

15

65 30

55 30

500

0

10

45

20

200

20

5

F

M

HH + HL grade

0

5

3

600

300


25

AC3 AC1

800

101

102

CARBODUR® 20 NiMoCrS 6-5 Material No. Code


Material No.

Designation

1.6757

20NiMoCrS6-5

C


Si

Mn

P

0.18– 0.28 max. 0.40 0.50 – 0.70




S

≤0.035

Cr

Ni

0.020–0.040 0.65 – 0.85 1.50 – 1.90 0.25–0.40


Soft-annealed A

170 – 220

max. 255

Mo

HB



max. 220

max. 180

155 – 205




900 – 950 °C


870 840 800 170

3)



– – – –

900 870 830 210


°C °C °C °C


4)

4) 4) 4)


3

5

7

9

11

13

15

20

25

30

35

40

H max. min.

49 39

49 39

48 38

47 37

46 36

45 35

44 33

44 32

42 30

41 28

39 26

38 25

38 23

HH max. min.

49 42

49 42

48 41

47 40

46 39

45 38

44 37

44 36

42 34

41 32

39 30

38 29

38 28

HL max. min.

46 39

46 39

45 38

44 37

43 36

42 35

40 33

40 32

38 30

37 28

35 26

34 25

33 23

Hardness in HRC



55

1200

HH-Sorte HH grade

1100


50

HH + HL grade

1000

HL-Sorte HL grade

900

Temperature Temperatur in in o°C C

45


40 35 30

AC3

800

AC1

A

700

3

500 400

100

20

20 80

85 85

85

90

89

15 0

5

10

15

20

25

30

35

40


45

87 25


15

72

Hardness 468 values Härtewerte

HV 10 0

-F -P

50

B 5

M 200

35

3

MS

300

25

50

48

15 43 10 30

5 3

600

468

468 442 421 383 297 297 285 274 254

101

102 100

236

221 206 181

103 101

160

104 102

105

106

103

104


101

102

27

CARBODUR® 20 MnCr 5 / 20 MnCrS 5 Material No. Code

Material No.

Designation

Material No.

Designation

1.7147

20MnCr5

1.7149

20MnCrS5


C


20 MnCr 5 0.17– 0.22 20 MnCrS 5 0.17– 0.22




Si

Mn

P

S

≤0.40 ≤0.40

1.10 – 1. 40 1.10 – 1.40

≤0.035 ≤0.035

≤0.035 1.00 – 1.30 0.020–0.040 1.00 – 1.30


Soft-annealed A

170 – 217

1)

Cr

HB



max. 217

max. 180

152 – 201




880 – 980 °C


880 860 780 150

3)



– – – –

980 900 820 200

Cooling Oil (water), hot bath 160 – 250 °C,

4)

Salt bath (580 – 680 °C), case-hardening box, air Oil (water), hot bath 160 – 250 °C 4) Oil (water), hot bath 160 – 250 °C 4) Oil (water), hot bath 160 – 250 °C 4) Air

°C °C °C °C

4)


3

5

7

9

11

13

15

20

25

30

35

40

H max. min.

49 41

49 39

48 36

46 33

43 30

42 28

41 26

39 25

37 23

35 21

34 –

33 –

32 –

HH max. min.

49 44

49 42

48 40

46 37

43 34

42 33

41 31

39 30

37 28

35 26

34 25

33 24

32 23

HL max. min.

46 41

46 39

44 36

42 33

39 30

37 28

36 26

34 25

32 23

30 21

29 –

28 –

27 –

Hardness in HRC



55

1200 1100

50

1000

HH grade HH-Sorte

45


900

HL-Sorte HL grade

800

oC Temperature Temperaturin in °C


AC3

HH + HL grade

35 30

700 A 400

MS

50

87

M

40

50

25

80 65

60

55 45 15

200 100

20


HV 10 0 100 Zeit Timeinins s

15 0

5

10

15

20

25

30

35

40


28

AC1

B

300

25

65 35

P

10 25 35

500

60 40

60 60 60 60 40 40 40

F

600

45

405

101

342 302 274 263 238 212 187 171 160 182 162 153

102 100 Zeit in in minmin Time

103 101

104 102 100 Zeit Timeininh h

105

106

103 101

104 102

CARBODUR® 20 MoCr 4 / 20 MoCrS 4 Material No. Code

Material No.

Designation

Material No.

Designation

1.7321

20MoCr4

1.7323

20MoCrS4


C


20 MoCr 4 0.17– 0.23 20 MoCrS 4 0.17– 0.23




Si

Mn

P

S

≤0.40 ≤0.40

0.70 – 1.00 0.70 – 1.00

≤0.035 ≤0.035

Mo

≤0.035 0.30 – 0.60 0.40 – 0.50 0.020–0.040 0.30 – 0.60 0.40 – 0.50


Soft-annealed A

156 – 207

1)

Cr

HB



max. 207

max. 165

140 – 187



Cooling


880 – 980 °C

Oil (water), hot bath 160 – 250 °C,4)

Direct hardening 3) Core refining Case refining Tempering (stress-relieving) 5)



880 860 780 150

– – – –

980 900 820 200

°C °C °C °C


4) 4) 4)


3

5

7

9

11

13

15

20

25

30

35

40

H max. min.

49 41

47 37

44 31

41 27

38 24

35 22

33 –

31 –

28 –

26 –

25 –

24 –

24 –

HH max. min.

49 44

47 40

44 35

41 32

38 29

35 26

33 24

31 22

28 –

26 –

25 –

24 –

24 –

HL max. min.

46 41

44 37

40 31

36 27

33 24

31 22

29 –

27 –

24 –

22 –

21 –

20 –

20 –

Hardness in HRC



55

1200 1100

50

1000



900

HL-Sorte HL grade

800



AC3

HH + HL grade

35 30

3

A

55

25

5 10

15

30

5

600

60

65

30

65

70

65 70

30

30

30

30

30

5

5

5

AC1

P

B 500

MS

95

400 300

25

F

700

95 95 95

M

90

85

70

15

10

200 100

20


HV 10 0 100 Zeit inins s Time

15 0

5

10

15

20

25

30

35

40


45

370

101

283

260 240 238 228 210

102 100 Zeit min Timein in min

189

176 165 181

103

152 156 149

104

101

102 100

105

106

103 101

104 102

Zeit ininh h Time

29

CARBODUR® 20 NiCrMo 2-2 / 20 NiCrMoS 2-2 Material No. Code

Material No.

Designation

Material No.

Designation

1.6523

20NiCrMo2-2

1.6526

20NiCrMoS2-2


C


20 NiCrMo 2-2 0.17– 0.23 20 NiCrMoS 2-2 0.17– 0.23




Si

Mn

P

S

≤0.40 ≤0.40

0.65 – 0.95 0.65 – 0.95

≤0.035 ≤0.035

Ni

Mo

≤0.035 0.35 – 0.70 0.40 – 0.70 0.15–0.25 0.020–0.040 0.35 – 0.70 0.40 – 0.70 0.15–0.25


Soft-annealed A

161 – 212

1)

Cr

HB



max. 212

max. 176

149 – 194

Heat treatments


Type of treatment



880 – 980 °C


880 860 780 150

– – – –

980 900 820 200


°C °C °C °C


4)

4) 4) 4)


3

5

7

9

11

13

15

20

25

30

35

40

H max. min.

49 41

48 37

45 31

42 25

36 22

33 20

31 –

30 –

27 –

25 –

24 –

24 –

23 –

HH max. min.

49 44

48 41

45 36

42 31

36 27

33 24

31 22

30 21

27 –

25 –

24 –

24 –

23 –

HL max. min.

46 41

44 37

40 31

36 25

31 22

29 20

27 –

26 –

23 –

21 –

20 –

20 –

– –

Hardness in HRC



55

1200 1100

50

1000



900

HL-Sorte HL grade

800


HH + HL grade

Hardness in HRC HRC Härte in

40 35 30

F

700 A

600 500

15

1

MS

5

P5

40 10

200 100

20 15 0

5

10

15

20

25

30

35

40


45

AC3

75

75 25

AC1

25

85 96

M

91

97

79 49

453 453 Härtewerte Hardness


5

234

values

HV 10 0

40

40

84

25

60

55

B 65

400 300

30

10

5

1

453

101

426 313

283 276 245 239

102 100 Zeit min Timein in min

210

182

159

103 101

148

140

104 102 100 Zeit ininh h Time

105

106

103 101

104 102

CARBODUR® 22 CrMoS 3-5 Material No. Code


Material No.

Designation

1.7333

22CrMoS3-5

C

Si

Mn

P

0.19–0.24

≤0.40

0.70–1.00

≤0.035

Hardness in various treatment conditions * For diameters up to 150 mm ** For diameters up to 60 mm

S

Cr

Mo

0.020–0.040 0.70 –1.00 0.40 – 0.50



Soft-annealed A

max. 255

170 – 217

HB



max. 217

max. 180

152 – 201

Heat treatments


Type of treatment



880 – 980 °C


880 860 780 150

– – – –

980 900 820 200


°C °C °C °C


4)

4) 4) 4)


3

5

7

9

11

13

15

20

25

30

35

40

H max. min.

50 42

49 41

48 37

47 33

45 31

43 28

41 26

40 25

37 23

35 22

34 21

33 20

32 –

HH max. min.

50 45

49 44

48 41

47 38

45 36

43 33

41 31

40 30

37 28

35 26

34 25

33 24

32 23

HL max. min.

47 42

46 41

44 37

42 33

40 31

38 28

36 26

35 25

32 23

31 22

30 21

29 20

28 –

Hardness in HRC

Hardenability diagram 55 50 HH-Sorte HH grade Überschneidung Overlap of HH+HL-Sorte

45

HH + HL grade

HL-Sorte HL grade Hardness HRC Härte ininHRC

40 35 30 25 20 15 0

5

10

15

20

25

30

35

40

45


31

Hardenability Effect of alloying elements

Fig. 1 shows an example of the ef-

For reasons of toughness, the

on hardenability

fect of alloying elements on the

carbon content is limited to about

Based on the composition of the

hardenability of various case-

0.25%. The element silicon also

alloys, case-hardening steels can

hardening steels according to

increases hardenability. It is, how-

be classified as:

DIN 10 084 in the end-quench

ever, hardly ever used as an alloy-

• unalloyed

test. The hardness at a distance

ing element in case-hardening

• chrome-alloyed

of 1.5 mm from the end surface is

steels because it encourages sur-

• manganese-chrome and molyb-

largely determined by the carbon

face oxidation on carburising. In

content. The shape of the rest of

special cases, boron is used as

• nickel-chrome-alloyed

the end-quench test curve is also

an alloying element to increase

• nickel-chrome-molybdenum-

influenced by the quantities of

hardenabililty or impact tough-

other elements, such as molyb-

ness in chrome-manganese

denum, manganese, chrome and

steels.

nickel, that tend to increase hard-

In the case of some unalloyed

enability. Given small cross-

case-hardening steels, the effect

The alloying elements affect the

sections, through-hardening is

of a coarse-grain austenite struc-

hardenability of the base material

possible with chrome or chrome-

ture is used to increase hardness.

and the hardenability of the car-

manganese steels, while higher

burised surface layer.

quantities of molybdenum and

denum-chrome-alloyed

alloyed and • chrome-nickel-molybdenumalloyed case-hardening steels.

case-hardening steels

nickel must be added to The hardenability of the base

achieve through hardening

material is identified by means of

of large cross-sections.

50

40 18 CrNiMo 7-6

the end-quench test according to 30 Hardness in HRC

DIN 50 191 and is an important parameter for determining hardness in the core, since casehardened components are only

17 CrNi 6-6 20 20 MoCr 4 17 Cr 3 10

16 MnCr 5

tempered at low temperatures, up to approximately 180 °C, in order to ensure high surface hardness.

32

Fig. 1 Effect of alloying elements on the hardenability of casehardening steels

0 10 20 30 Distance from quenched end in mm

40

50

Technical information

carburisation, the heating and

Fig. 2 shows the case depth of

on hardness in the core, the

cooling conditions during hard-

various case-hardening steels

hardness and the hardness profile

ening and the hardenability in the

with the same carbon distribution

in the carburised surface layer

carburised surface layer.

in the surface layer. According to

have an important effect on the

Correlations valid for the base

this, case depth of the 17 Cr 3

properties of case-hardened

material cannot be applied to the

steel (0.80 mm) is doubled in the

components. A surface hardness

hardenability of the surface layer,

17 CrNi 6-6 steel (1.56 mm) due to

of 57 - 63 HRC has proved to the

since the effect of alloying ele-

the different alloy contents under

best for optimum wear resistance.

ments on hardenability also

otherwise identical conditions.

This degree of hardness is

depends on the carbon content.

%

achieved largely independently of

Up to a carbon content of about

0.90

the steel composition, with a car-

0.5%, the improvement in harden-

0.80

bon content at the surface of

ability brought about by molyb-

some 0.7%. Higher carbon con-

denum, chrome and manganese

tents in the surface layer provide

increases, only to drop again at

layer may result in reduced toughness due to precipitation of secondary cementite and a hardness loss caused by increasing proportions of residual aus-

0.70

17 Cr 3 20 NiCrMo 2-2 20 MoCr 4 16 MnCr 5 20 NiMoCr 6-5 17 CrNi 6-6

C

0.60

0.60

0.50 1.50 mm

0.46 0.40

0.39

0.37 0.34 0.33

0.30 0.20 0.10 0

Eht 0

0.4

0.8

0.35 % C

1.16 1.35 1.42 1.52 1.56

Supercarburisation in the surface

higher carbon contents.

(acc. to U. Wyss)

0.80

only a slight increase in hardness.

Carbon content in % by weight

Quite apart from their influence

1.2

1.6

2.0

2.4

2.8

Distance from the surface in mm

Fig. 2: Case depth of various case-hardening steels with the same carbon profile (acc. to U. Wyss)

tenite.

The case depth, defined as the distance from the surface of a case-hardened workpiece to the point whose Vickers hardness is usually 550 HV1 (see DIN 50 190), is determined by the depth of

33

Suitability for direct

direct hardening are satisfactory

steels with 1.6 to 1.8% chrome is

hardening

fine-grain stability at the carburis-

appreciably higher than, for exam-

An important criterion in the

ing temperature and low residual

ple, in the 20 MoCr 4 steel with

choice of a case-hardening steel

austenite after hardening. The

approximately 0.4% chrome. The

is its suitability for direct harden-

residual austenite content after

hardness decreases at carbon

ing. The most common methods

hardening increases with increas-

contents > 0.7% at the surface,

of case hardening are direct hard-

ing chrome content and carburis-

which increases the proportions

ening (Fig. 10, Hardening from the

ing temperature. Fig. 3 illustrates

of residual austenite (Fig. 4). direct hardening

carburisation heat) and single

this relationship, using the

hardening after cooling from the

20 MoCr 4, 20 NiMoCr 6 5,

case (Fig. 11). Mainly for reasons

16 MnCr 5, 20 MnCr 5,

of cost effectiveness, direct hard-

17 CrNi 6-6 and 18 CrNi 8

ening is increasingly being given

steels as examples.

preference in mass production

Although differences in the

methods (see chapter on Heat

proportions of residual aus-

Treatment).

tenite in the various steels

The prerequisites for the suitability

remain relatively small at carbu-

of a case-hardening steel for

rising temperatures around 900 °C

100

Hardness in HV 0.5

900 800 700

Direct hardening 925 °C/oil

600 500

20 MoCr 4 20 NiMoCr 6-5 18 CrNi 8 16 MnCr 5

400 300 0

0.1 0.2 0.3

0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 Carbon Content in % by weight

Fig. 4: Hardness as a function of the carbon content of the surface layer after direct hardening

with subsequent direct hardening,

chrome content of the steels tested

60 Carborising 50 temperature 1000 in °C: 40

18 CrNi 8

17 CrNi 6-6

20 MnCr 5

70

16 MnCr 5

Residual austenite content in %

80

20 MoCr 4

90

20 NiMoCr 6-5

Carborising time: 3 h

950

30

The suitability of a steel for direct

gressively at higher carburising

hardening can also be identified

temperatures. For economic rea-

by the range of carbon contents

sons, however, ever higher car-

at the surface with which a cer-

burising temperatures are being

tain minimum hardness can be

aimed at for direct hardening.

achieved. According to this, the

Given the same carburising time

20 MoCr 4 steel is more suitable

and the same carbon potential in

for direct hardening than, for

the carburising medium, the pro-

example, the 18 CrNi 8 steel.

portion of residual austenite in

Advances in the development of

the 17 CrNi 6-6 and 18 CrNi 8

modern gas carburising plants,

20 10 0

900 0.4 0.6 0.8 1.0 1.2 1.4 Chrome content in % by weight

1.6

1.8

Fig. 3: Residual austenite content as a function of chrome content and carburising temperature

34

they increase rapidly and pro-


with their precise, specific control

remains bound in the form of car-

and torsional stresses, the fatigue

of the carbon potential and the

bide (Fig. 10 and 11).

strength increases with increasing

carburising cycle, mean that

case depth and core strength. In

Fatigue strength

the unusual case of tensile/com-

steels can be direct-hardened,

In addition to higher wear resis-

pression stressing, the signifi-

regardless of their alloy content.

tance, case-hardened steels

cance of the core strength in-

Fig. 5 shows the different carbon

should also exhibit high strength

creases. The alloying elements

contents at the surface that have

under dynamic stressing. On

affect fatigue strength through the

to be chosen for various case-

hardening a cross-section with a

hardenability in the core and the

hardening steels in order to en-

carburised surface layer, the

surface layer and also through the

sure maximum surface hardness.

lower-carbon core undergoes

residual austenite content.

transformation before the high0.9

carbon surface layer due to the higher martensite temperature.

0.8

Since the martensite transforma0.7

0.5

0.3 0.5 0.7 0.9 1.1 1.3 1.5 Chrome content in % by weight

crease in volume, high internal

18 CrNi 8

17 CrNi 6-6

20 MnCr 5

16 MnCr 5

0.6

tion is accompanied by an in20 MoCr 4

Carbon content in the surface layer in % by weight

practically all case-hardening

1.7

compression stresses develop 1.9

2.1

that are balanced by internal tensile stresses. The compression

Fig. 5: Carbon content in the surface layer targeted during direct hardening to obtain maximum possible hardness as a function of the chrome content

stresses in the surface layer counteract the external, usually tensile, stresses and thus increase the fatigue strength.

The proportions of residual austenite are appreciably lower after

The fatigue strength of case-

single hardening since, on hard-

hardened components also

ening from lower temperatures

depends on the ratio of the car-

adjusted to the carbon content at

burised surface layer to the non-

the surface, any excess carbon

carburised section. With bending

35

Austenite grain size

Toughness of the surface

To date, no standard test for the

Fine-grain stability in case-

layer under impact loading

characterisation of the impact

hardening steels is particularly

Case-hardened components must

toughness of case-hardened

important at the high tempera-

remain ductile under high dynam-

steels has been accepted. One

tures reached during direct hard-

ic stressing in order to avoid

frequently used method is the

ening, due to the fact that grain

brittle factures. Since the high-

Brugger test, with which the

growth with coarse or mixed grain

carbon martensite in the surface

maximum impact strength of a

can lead to the danger of distor-

layer exhibits only low toughness,

case-hardened notched impact

tion and reduced toughness. By

the toughness of the component

specimen is measured.

selectively balancing the quanti-

is determined largely by the

ties of aluminium and nitrogen,

depth of the carburised surface

the inhibiting effect of aluminium

layer and the toughness of the

nitride precipitations on grain

core material. The impact tough-

growth can be used to achieve a

ness of the component dimin-

largely stable fine-grain structure.

ishes with increasing case depth.

According to DIN 17 210, fine

For reasons connected with the

grain structure is assured after

fatigue strength, however, the

treatment at 930 +/- 10 °C/4 h/

case depth should not be too

water. Prior hot forming and heat

small. The toughnesss of the sur-

treatments can have a significant

face layer can be improved by

effect on the stability of the fine

choosing a nickel content > 1.5%.

grain. In disputed cases, annealing treatment at 1150 °C/30 min/ air is recommended as pretreatment, in order to produce a uniform initial state.

36


Machining and heat treatment Chipless forming

steels tend to “smear” and form

Heat treatments for as-

Case-hardening steels are well

built-up edges. In such cases,

supplied conditions

suited to hot forming. Due to the

heat treatment to a particular

Depending on the product con-

low carbon content, they possess

strength (“TH”) is of advantage.

cerned and the anticipated pro-

good cold-working properties

With high-alloy nickel-chrome or

cessing, case-hardening steels

that, however, deteriorate with

nickel-chrome-molybdenum case-

can be supplied in various treated

increasing carbon and alloy con-

hardening steels, the transition to

conditions. The most important

tents. Depending on the chemical

the ferrite-pearlite stage is often

heat treatments are described

composition, the choice of a suit-

incomplete, leaving traces of

below. Table 1 provides an over-

able structure (AC, FP) can im-

bainite and a banded structure

view of the Brinell hardness

prove cold-forming properties.

that reduce machinability. These

values that should be chosen for

steels are therefore also ma-

these conditions.

Chip machining

chined in the AC-annealed condi-

Chip machining of case-harden-

tion.

Treatment for shearing S

ing steels is affected by the struc-

(Fig. 6, Curve 1)

tural state, the strength and non-

Case-hardening steels are fre-

Appropriate cooling and/or

metallic inclusions (sulphides,

quently produced with a con-

annealing to achieve a maximum

oxides).

trolled sulphur content of 0.020 -

hardness of 255 HB.

0.035%. Machinability is then Ferritic-pearlitic structures, such

improved by an increase in sul-

as can be achieved with un-

phide inclusions. Deliberate con-

alloyed or low-alloy case-harden-

trol of the oxide inclusions

ing steels like Ck 15 and 17 Cr 3

(calcium treatment) also

by controlled cooling from the

allows the machinability of

forming temperature, are espe-

case-hardening steels to

ing. Special heat treatment (FP

be changed for the better.

AC3

AC1

4 Temperature

cially well suited for chip machin-

Fig. 6: Schematic representation of the temperature/time profile when treating for shearing (S), soft-annealing (A) and annealing to spherical carbides (AC)

2 Soft annealing, A 3 1 annealing to spherical, AC Treating for shearing, S

annealing) is required for higheralloyed steels. At very low hardness values, case-hardening

Time

37

Hardnesses in treated condition1)

Steel grade Code name

Material No.

S (treated for shearing)

A (soft-annealed)

TH1) (treated for strength)

FP2) AC (treated for ferrite(annealed to pearlite structure) spherical carbides)

HB max.

HB max.

HB

HB

HB max.

C 15 E C 15 R

1.1141 1.1140

– –

143 143

– –

– –

135 135

17 Cr 3

1.7016

–

174

–

–

155

16 16 20 20

MnCr 5 MnCrS 5 MnCr 5 MnCrS 5

1.7131 1.7139 1.7147 1.7149

– – 255 255

207 207 217 217

156 156 170 170

20 MoCr 4 20 MoCrS 4

1.7321 1.7323

255 255

207 207

22 CrMoS 3-5

1.7333

255

20 NiCrMo 2-2 20 NiCrMoS 2-2

1.6523 1.6526

20 NiMoCrS 6-5

187 187 201 201

165 165 180 180

156 to 207 156 to 207

140 to 187 140 to 187

165 165

217

170 to 217

152 to 201

180

2553) 2553)

212 212

161 to 212 161 to 212

148 to 194 148 to 194

176 176

1.6757

255

220

170 to 220

155 to 205

180

17 CrNi 6-6 18 CrNi 8

1.5918 1.5920

255 255

229 225

175 to 229 179 to 229

156 to 207 158 to 205

178 180

18 CrNiMo 7-6

1.6587

255

229

179 to 229

159 to 207

180

15 NiCr 13

1.5752

255

229

179 to 229

166 to 217

180

Table 1: Brinell hardness in various treatment conditions

to to to to

207 207 217 217

140 140 152 152

For diameters up to 150 mm For diameters up to 60 mm 3) Can be sheared in as-rolled condition 1) 2)

Soft annealing A (Fig. 6, Curve 2) Heat treatment for reducing the hardness of a workpiece to values below a certain prescribed value.

38

to to to to


transformation temperatures in TTT-Diagram (continous) 1000

the pearlite stage for the most

Temperature

900 800

AC3

AC3

700

AC1

AC1

A

600

2

500

1

F

P 1

MS

300

The transformation time depends on the temperature cycle, the size

B

400

common case-hardening steels.

1

of the workpiece and the state of

M

3

200

nucleation of the austenite after

100 0 Time (log.)

Time in h

t

= Start of transformation

A Austenite range

B

range of bainite structure

= End of transformation

F Ferrite range

M

Martensite range

t

forging. Considerably longer transformation times are necessary at other transition tempera-

P Pearlite range

Treating for strength (TH)

Treating for ferrite-pearlite structure (FP)

(Fig. 7, Curve 1) Heat treatment with appropriate

(Fig. 8, Curve 1)

cooling and subsequent temper-

(also called “pearlitising, isother-

ing in order to achieve a certain

mal annealing”) Isothermal trans-

range of hardness.

formation, consisting of austenit-

20 NiMoCr 6-5

650

18 CrNiMo 7-6

660

18 CrNi 8

650 20 MoCr 4

660

17 CrNi 6-6

650

20 NiMoCr 2-2

640

20 MnCr 5

640

16 MnCr 5

640 0

ising, subsequent cooling to a temperature in the pearlite

TTT-Diagram (isothermal)

Temperature in °C

Fig. 7: Schematic representation of the temperature/time profile for TH annealing ➀, hardening ➁ und tempering ➂

transition temperature in °C

tures in the pearlite stage.

20

40

60

80

100

120

Pearlitising time in minutes

Fig. 9: Time ranges for complete transformation to pearlite for various casehardening steels (austenitising temperature range 870-900 °C) * Acc. to P. G. Dressel and H. Gulden

1000

stage and holding, so that

Temperature in oC

900

AC3

800 700 600

P

500 400 300

AC1

F

A

1

B

MS M

the austenite is trans-

Annealing to spherical

formed completely into

carbides AC (Fig. 6, Curves 3, 4)

ferrite-pearlite. Fig. 9

Annealing with the aim of spher-

shows the shortest trans-

oidising the carbides. This gener-

formation times at ideal

ally comprises holding for a

200 100 0

Time (log.)

lengthy period of time at a tempe-

t

= Start of transformation

A Austenite range

B

= End of transformation

F Ferrite range

M Martensite range

P Pearlite range

range of bainite structure

Fig. 8: Schematic representation of the temperature/time profile for pearlitising (FP)

rature near AC1, oscillating about this temperature, if necessary.

39

Case-hardening treatment Case hardening consists of the

A distinction is therefore made

piece exhibit different AC3 and MS

following stages:

between:

temperatures and also different

1. Carburising of the surface

Powder carburising,

transformation behaviour.

layer to certain case depths

Salt bath carburising,

The most favourable hardening

and certain carbon contents in

Gas carburising.

temperatures for the core are

the layer.

approx. 100 °C above those for

2. Subsequent hardening.

The quantity of carbon introduced

the surface layer (see Material

3. Tempering (stress-relieving).

into the surface layer is primarily

Data Sheets, Page 22 ff.). In prac-

dependent on the carburising

tice, this behaviour leads to

For the carburising and hardening

effect of the medium. The case

various treatment cycles.

stages, there are various proven

depth depends mainly on the

processing cycles that are

temperature and duration of the

chosen on the basis of technical

treatment. Since the rate of diffu-

and economic aspects.

sion increases with rising temperatures, the time required to reach

Carburising

the desired case depth is reduced

Carburising means the thermo-

at higher temperatures. Similarly,

chemical treatment of a work-

the gradient of the carbon con-

piece in the austenitic condition

tent from the surface to the core

with the aim of enriching the sur-

becomes flatter.

Hardening

face layer with carbon. After this treatment, the carbon is usually in

In order for the surface hardness to

(Fig.7, Curve 2)

the austenite in solid solution.

be high enough and, at the same

Hardening is taken to mean heat

time, for residual austenite and

treatment consisting of austenitis-

Carburising takes place in a

secondary cementite to be elimi-

ing and cooling, under conditions

medium which releases carbon.

nated as far as possible, it is nec-

leading to an increase in hard-

The carburising medium can be a

essary to aim for a carbon content

ness due to more or less com-

solid (powder), liquid or gas.

at the surface which is below that

plete transformation of the aus-

of the eutectic composition.

tenite into martensite and possi-

In line with their carbon content,

bly bainite.

the surface and core of the work40


Single hardening

Quenching after carburising is Carburisation (gas or salt bath)

preferably carried out in oil. For Temperature

Ac3 (core) Ac3 (surface)

workpieces of complicated design, hot bath hardening at approximately 160 - 250 °C, followed by cooling in air, is advis-

V

Hardening (oil)

hardening process carried out

Tempering

after prior carburising and cooling Time

10

Single hardening means a single

Direkthärten

Direct Hardening

Fig. 10: Direct hardening

able. For coarser workpieces of

to ambient temperature. If carburising is followed by isothermal transformation, this is referred to

simple design, quenching in water

The time required for the case-

as single hardening with isother-

can be chosen. In order to trans-

hardening of steels can be con-

mal transformation.

form larger proportions of residu-

siderably reduced by ensuring a

al austenite into martensite after

high carbon potential during the

In the case of single hardening,

hardening, final subzero cooling

actual carburising phase and the

the carburised parts are first

to -180 °C can be carried out, e.g.

subsequent diffusion period,

cooled slowly in the carburising

on CrNi and CrNiMo steels.

and/or by using high tempera-

vessel and then hardened in the

tures. Since higher carburising

usual way, possibly after interme-

Direct hardening (Fig. 10)

temperatures have a negative

diate treatment. The hardening

Direct hardening means quench-

effect on attempts to minimise

temperatures used usually lie just

ing immediately after carburising

distortion when quenching, it is

above the AC3 point of the surface

treatment that has been carried

expedient to let the temperature

layer. It is, however, also possible

out in the austenite temperature

drop somewhat after carburising

to choose hardening tempera-

range.

and then quench from a lower

tures that are just above or below

During the direct hardening of

temperature that is still sufficient

the AC3 point of the core.

case-hardening steels, quenching

for hardening (denoted V). This is

is carried out immediately after

especially true for parts with a

carburising, either directly from

complex design. Distortion can

the case temperature or after a

be minimised in this way.

short pause (V in Fig. 10). This method is mainly used in connection with gas carburising in the mass production of gearing components. 41

Single hardening after cool-

hardening lie in the fact that the

face layer. Traces of residual aus-

ing from the case (Fig. 11)

non-carburised area remains

tenite should favour smooth run-

When hardening from tempera-

machinable, even after quench-

ning of gear wheels, for example,

tures just slightly above the AC3

ing, and that distortion remains

and also facilitate running-in.

value for the surface, only partial

negligible due to the low harden-

Quite apart from that, a surface

transformation occurs in the core

ing temperature.

layer absolutely free of residual

The disadvantage is that

austenite is, for many alloyed

low toughness in the core

case-hardening steels, virtually

must be expected.

impossible without the use of

Carburisation Temperature

C

Ac3 (core) Ac3 (surface)

Hardening (oil) Cooling (case or air)

Tempering

special methods (e.g. low-

Time

When hardening from temFig. 11: Single hardening after cooling from the case

temperature treatments)

peratures that are above the AC3 temperature of the core (C in Fig.

Single hardening after inter-

because the hardening tempera-

11), the core undergoes complete

mediate annealing (Fig. 12)

ture is then under the AC3 value

transformation, becomes fine-

In certain cases, for example the

for the core. The core then re-

grained and thus gains in strength

elimination of distortion caused

mains soft and can have a coarse

and toughness. Although the

by carburising and cooling, it can

structure as a result of the long

grain of the surface layer then

be expedient to introduce an

holding time at the high carburis-

becomes somewhat coars-

ing temperature. In the case layer,

er, any cementite lattice is

Carburisation C Temperature

Intermediate annealing

Hardening (oil)

Ac3 (core) Ac3 (surface) Ac1 (core)

on the other hand, a hard, fine-

dissolved and surface em-

grain, homogeneous structure

brittlement eliminated.

develops that provides good wear

Since, on hardening from

and fatigue strength properties. If

high temperatures, the amount of

cementite has formed, precipi-

residual austenite in the carbu-

tated out at the grain boundaries

rised surface layer increases with

intermediate processing stage

as a lattice pattern, the low hard-

increasing carbon content, espe-

before hardening. To this end, the

ening temperature is not sufficient

cially with alloyed case-hardening

parts are subjected to interme-

to dissolve the cementite lattice.

steels, it is advisable to aim for a

diate annealing below the AC1

The advantages of this method of

lower carbon content in the sur-

temperature.

Cooling (case or air)

Tempering

Time

42

Fig. 12 Single hardening after intermediate annealing


Single hardening after iso-

Double hardening (Fig. 14)

Tempering

thermal transformation

Double hardening means two

(Fig. 7, Curve 3)

(Fig. 13)

stages of hardening, in which

Tempering means the single or

This method of treatment is suit-

quenching is generally carried out

repeated heating of a hardened

able for high-alloy case-hardening

from different temperatures.

workpiece to a prescribed tem-

steels (e.g. 18 CrNi 8) that show a

With carburised workpieces, the

perature (< AC1), holding at this

tendency to stress corrosion

first hardening process can be

temperature and subsequent

direct hardening, while the Carburisation Temperature

C

Ac3 (core) Ac3 (surface) Pearlite stage (core)

Hardening (oil) Salt bath Isothermal transformation

appropriate cooling.

second is carried out from a lower temperature.

After hardening, it is advisable to

Tempering

temper the workpieces at 150 Time

t

13

Double hardening is usual-

Single hardening after isothermal transformation

180 °C for unalloyed steels and at

ly used when tough surface layers

170 - 210 °C for alloyed steels.

and core zones are required,

Martensite tempered in this way

cracking after cooling in air from

together with greater case depth.

has less of a tendency to form

the case, due to differences in the

Double hardening is generally

grinding cracks. The hardness in

transformation rates between the

carried out first from the AC3

the surface layer drops only

surface and the core.

temperature of the core and then

slightly (approx. 1 - 2 HRC).

Fig. 13: Single hardening after isothermal transformation

from the AC3 temperature of the surface area. The tendency to distortion is greatest with double hardening.

Temperature

Carburisation Ac3 (core) Ac3 (surface) Hardening (oil)

Hardening (oil) Tempering

Time

4

Double hardening

Fig. 14: Double hardening

43

Overview of grades and chemical composition Overview of grades Carbodur

Code name

Carbodur C 15 E

C 15 E

Carbodur C15 R

C15 R

Carbodur 17 Cr 3

Chemical composition Main alloy contents in % (typical values) Material No.

C

Si

Mn

P max.

S

Cr

Ni

Mo

1.1141

0.12-0.18

≤0.40

0.30-0.60

1.1140

0.12-0.18

≤0.40

0.30-0.60

0.035

≤0.035

–

–

–

0.035

0.020-0.040

–

–

–

17 Cr 3

1.7016

0.14-0.20

≤0.40

0.60-0.90

0.035

≤0.035

0.70-1.00

–

–

–

Carbodur 16 MnCr 5

16 MnCr 5

1.7131

0.14-0.19

≤0.40

1.00-1.30

0.035

≤0.035

0.80-1.10

–

Carbodur 16 MnCrS 5

16 MnCrS 5

1.7139

0.14-0.19

≤0.40

1.00-1.30

0.035

0.020-0.040

0.80-1.10

–

–

Carbodur 20 MnCr 5

20 MnCr 5

1.7147

0.17-0.22

≤0.40

1.10-1.40

0.035

≤0.035

1.00-1.30

–

–

Carbodur 20 MnCrS 5

20 MnCrS 5

1.7149

0.17-0.22

≤0.40

1.10-1.40

0.035

0.020-0.040

1.00-1.30

–

–

Carbodur 20 MoCr 4

20 MoCr 4

1.7321

0.17-0.23

≤0.40

0.70-1.00

0.035

≤0.035

0.30-0.60

–

0.40-0.50

Carbodur 20 MoCrS 4

20 MoCrS 4

1.7323

0.17-0.23

≤0.40

0.70-1.00

0.035

0.020-0.040

0.30-0.60

–

0.40-0.50

Carbodur 22 CrMoS 3-5

22 CrMoS 3-5

1.7333

0.19-0.24

≤0.40

0.70-1.00

0.035

0.020-0.040

0.70-1.00

–

0.40-0.50

Carbodur 20 NiCrMo 2-2

20 NiCrMo 2-2

1.6523

0.17-0.23

≤0.40

0.65-0.95

0.035

≤0.035

0.35-0.70 0.40-0.70 0.15-0.25

Carbodur 20 NiCrMoS 2-2

20 NiCrMoS 2-2

1.6526

0.17-0.23

≤0.40

0.65-0.95

0.035

0.020-0.040

0.35-0.70 0.40-0.70 0.15-0.25

Carbodur 20 NiMoCrS 6-5

20 NiMoCrS 6-5

1.6757

0.17-0.23

0.15-0.40 0.60-0.90

0.035

0.020-0.035

0.30-0.50 1.40-1.80 0.40-0.50

Carbodur 17 CrNi 6-6

17 CrNi 6-6

1.5918

0.14-0.20

Carbodur 18 CrNi 8

18 CrNi8

1.5920

0.15-0.20

Carbodur 18 CrNiMo 7-6

18 CrNiMo 7-6

1.6587

0.15-0.21

Carbodur 15 NiCr 13

15 NiCr 13

1.5752

0.14-0.20

Table 2: Overview of grades and chemical composition of the steels

Table 2 contains an overview of the most common case-hardening steels that, with the exception of the 18 CrNi 8 and 20 NiMoCr 6-5 steels, are included in standard DIN EN 10 084, together with the chemical composition of the case-hardening steels.

44

0.50-0.90

0.035

≤0.035

1.40-1.70 1.40-1.70

–

0.15-0.40 0.40-0.60

0.035

≤0.035

1.80-2.10 1.80-2.10

–

≤0.40

0.50-0.90

0.035

≤0.035

1.50-1.80 1.40-1.70 0.25-0.35

≤0.40

0.40-0.70

0.035

≤0.035

0.60-0.90 3,00-3,50

≤0.40

–


Permissible deviations between check analysis and melt analysis Element

Maximum permissible content in the melt analysis

Permissible deviations of the check analysis1) from the limits for the melt analysis to DIN EN 10084

C

≤0.31

±0.02

Si

≤0.40

+0.03

≤1.00

±0.04

Mn

>1.00≤1.40

±0.05

P

≤0.035

±0.005

S

≤0.040

+0.0052)

Cr

≤1.80

±0.05

Mo

≤0.30

±0.03

>0.30≤0.50

±0.04

≤2.00

±0.03

>2.00≤3.50

±0.07

Ni

1) ± means that, for a given melt, either the upper or the lower limit of the range given for the melt analysis in Table 2 may be exceeded, but not both at once. 2) For steels with a range of 0.020 bis 0.040% sulphur according to the melt analysis, the deviation from the limit is ±0.005%.

Comparison of international standards Carbodur

Material No.

Code name to DIN EN 10084

Standardised in

USA SAE/ASTM

Japan JIS

Carbodur C 15 E

1.1141

C 15 E

DIN EN 10084

1015

S 15

Carbodur C 15 R

1.1140

C 15 R

DIN EN 10084

–

–

Carbodur 17 Cr 3

1.7016

17 Cr 3

DIN EN 10084

–

–

Carbodur 16 MnCr 5

1.7131

16 MnCr 5

DIN EN 10084

5115

–

Carbodur 16 MnCrS 5

1.7139

16 MnCrS 5

DIN EN 10084

–

–

Carbodur 20 MnCr 5

1.7147

20 MnCr 5

DIN EN 10084

5120

SMnC 420 H

Carbodur 20 MnCrS 5

1.7149

20 MnCrS 5

DIN EN 10084

–

–

Carbodur 20 MoCr 4

1.7321

20 MoCr 4

DIN EN 10084

–

–

Carbodur 20 MoCrS 4

1.7323

20 MoCrS 4

DIN EN 10084

–

–

Carbodur 22 CrMoS 3-5

1.7333

22 CrMoS 3-5

DIN EN 10084

–

–

Carbodur 20 NiCrMo 2-2

1.6523

20 NiCrMo 2-2

DIN EN 10084

8620

SNCM 220 (H)


1.6526

20 NiCrMoS 2-2

DIN EN 10084

–

–


1.6757

20 NiCrMoS 6-5

–

–

–

Carbodur 17 CrNi 6-6

1.5918

17 CrNi 6-6

DIN EN 10084

–

–

Carbodur 18 CrNi 8

1.5920

18 CrNi 8

–

–

–

Carbodur 18 CrNiMo 7-6

1.6587

18 CrNiMo 7-6

DIN EN 10084

–

–

Carbodur 15 NiCr 13

1.5752

15 NiCr 13

DIN EN 10084

3310 / 3415 / 9314

SNC 815 (H)

45

Forms supplied Product

Bar steel and round billets for tubemaking rolled

Dimensions

55 – 250 mm dia.

Tolerances Dia. or edge length

Lengths

Straightness

DIN 1013

Subject to purchase order

≤ 80 mm: 4.0 mm/m

> 200 mm dia. standard incompany tolerance, closer tolerance on request Sharp-edged 50 – 103 mm square

DIN 1014

Flat: Width: 80 – 510 mm Thickness: 25 – 160 mm Width/thickness ratio 10:1 max

DIN 1017 up to 150 mm width and 60 mm thickness; over 150 mm width standard in-company tolerance

Sheet bars rolled with bulbous narrow face

Width: 25 – 160 mm

Tolerance on request

Semis rolled

50 – 320 mm square, rising in 1 mm increments

Special:*) ≤ +100/-0

> 80 mm: 2.5 mm/m

Lengths/ weights

4.0 – 10 m, Hot-sawn other lengths or hot abrasion request ve-cut

Special:*) ≤ 100 mm +/- 1% of edge length

As-supplied condition

Surface finish

Untreated

Rough-peeled finish available for 52 Cold-sheara240 mm ble Max. permissible Special:*) Cold-sawable surface defect depCold-sawn, ths: cold abrasive- Normalized cut Round: 1% max. of Treated to dia. + 0.05 mm ferrite-pearlite Square: 1% max. of structure edge length Treated to Flat: 1.5% max. of hardness width, 2.0% max. of range thickness Soft-annealed Special:*) Spheroidize- Smaller surface defect depth on annealed request Stress-relieved

< 1000 mm2: 4.0 mm/m > 1000 mm2: 2.5 mm/m Special:*) Specially straightened

Thickness: 80 – 550 mm < 210 mm +/- 2% > 210 mm +/- 3% of edge length

End condition

≤ 210 mm square: hot-sawn or hot abrasive-cut

Standard: 6 mm/m Special:*) 4 mm/m

> 210 mm square: hot-sheared

> 100 mm – 210 mm +/- 1.5% of edge length

Special:*) Cold abrasivecut, cold-sawn

Quenched Edge radius: and tempered < 210 mm - 12-18% of edge length > 210 mm: without defined edge radius Max. perm. surface defect depth: ≤ 140 mm sq. 0.3 mm max. > 140 - 200 mm sq. 0.6 mm max. > 200 mm sq. visible defects eliminated

Bar steel and semis forged

65 – 750 mm dia.

DIN 7527

265 – 650 mm square

Bar steel: to DIN within the tolerance limit

flat: on request

Bright steel peeled

52 – 400 mm dia.

ISA Tol. 11 or comparable tolerance

peeled and polished

52 – 300 mm dia.

ISA Tol. 11 or comparable tolerance

ground

52 – 100 mm dia.

As-cast ingots/c.c. blooms Open-die forgings

on request

Semis: as-forged straightness

ISA-Tol. 8 or comparable tolerance

As-peeled straightness ≤ 2 mm/m, 1 mm/m or closer as a function of dimensions on request

Lengths as a function of dimensions and heattreatment condition on request

Hot abrasivecut or coldsawn

3 - 10 m, on request 30 m max. as a function of dia. and max. bar dead weight of 7 t

Hot-sawn/hot abrasive-cut

3–8m

Forgings forged to shape on request (drawing)

*) Special finishes subject to further inquiry (partly dependent on quality, dimensions and condition)

46

Special:*) Cold abrasivecut

Special:*) Cold-sawn/ abrasive-cut Dimensions 50 - 105 mm with round chamfer 30° or 45°, chamfer width approx. 5 -12 mm, other widths by arrangement

Special:*) - Rough-peeled - Turned - Milled

Technically crack-free condition e.g. eddycurrent tested or comparable technique, defined depth of roughness and suitable packaging by special arrangement

Hardness comparison table Tensile strength, Brinell, Vickers and Rockwell hardness Tensile strength Rm N/mm2 255 270 285 305 320 335 350 370 385 400 415 430 450 465 480 495 510 530 545 560 575 595 610 625 640 660 675 690 705 720 740 755 770 785 800 820 835 850 865 880 900 915 930 950 965 995 1030 1060 1095 1125 1155 1190 1220 1255 1290 1320 1350 1385 1420 1455 1485 1520 1555 1595 1630 1665 1700 1740 1775 1810 1845 1880 1920 1955 1995

Brinell hardness Ball indentation mm d HB 6.63 6.45 6.30 6.16 6.01 5.90 5.75 5.65 5.54 5.43 5.33 5.26 5.16 5.08 4.99 4.93 4.85 4.79 4.71 4.66 4.59 4.53 4.47 4.43 4.37 4.32 4.27 4.22 4.18 4.13 4.08 4.05 4.01 3.97 3.92 3.89 3.86 3.82 3.78 3.75 3.72 3.69 3.66 3.63 3.60 3.54 3.49 3.43 3.39 3.34 3.29 3.25 3.21 3.17 3.13 3.09 3.06 3.02 2.99 2.95 2.92 2.89 2.86 2.83 2.81 2.78 2.75 2.73 2.70 2.68 2.66 2.63 2.60 2.59 2.57

76.0 80.7 85.5 90.2 95.0 99.8 105 109 114 119 124 128 133 138 143 147 152 156 162 166 171 176 181 185 190 195 199 204 209 214 219 223 228 233 238 242 247 252 257 261 266 271 276 280 285 295 304 314 323 333 342 352 361 371 380 390 399 409 418 428 437 447 (456) (466) (475) (485) (494) (504) (513) (523) (532) (542) (551) (561) (570)

Rockwell hardness

Vickers hardness HV 80 85 90 95 100 105 110 115 120 125 130 135 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240 245 250 255 260 265 270 275 280 285 290 295 300 310 320 330 340 350 360 370 380 390 400 410 420 430 440 450 460 470 480 490 500 510 520 530 540 550 560 570 580 590 600

HRB – 41.0 48.0 52.0 56.2 – 62.3 – 66.7 – 71.2 – 75.0 – 78.7 – 81.7 – 85.0 – 87.1 – 89.5 – 91.5 92.5 93.5 94.0 95.0 96.0 96.7 – 98.1 – 99.5 – (101) – (102) – (104) – (105) – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – –

HRC

HR 30 N

– – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – 20.3 21.3 22.2 23.1 24.0 24.8 25.6 26.4 27.1 27.8 28.5 29.2 29.8 31.0 32.2 33.3 34.4 35.5 36.6 37.7 38.8 39.8 40.8 41.8 42.7 43.6 44.5 45.3 46.1 46.9 47.7 48.4 49.1 49.8 50.5 51.1 51.7 52.3 53.0 53.6 54.1 54.7 55.2

– – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – 41.7 42.5 43.4 44.2 45.0 45.7 46.4 47.2 47.8 48.4 49.0 49.7 50.2 51.3 52.3 53.6 54.4 55.4 56.4 57.4 58.4 59.3 60.2 61.1 61.9 62.7 63.5 64.3 64.9 65.7 66.4 67.1 67.7 68.3 69.0 69.5 70.0 70.5 71.2 71.7 72.1 72.7 73.2

Tensile strength Rm N/mm2

Brinell hardness Ball indentation mm d HB

2030 2070 2105 2145 2180 – – – – – – – – – – – – – – – – –

2.54 2.52 2.51 2.49 2.47 – – – – – – – – – – – – – – – – –

Rockwell hardness

Vickers hardness

(580) (589) (599) (608) (618) – – – – – – – – – – – – – – – – –

HV

HRB

HRC

HR 30 N

610 620 630 640 650 660 670 680 690 700 720 740 760 780 800 820 840 860 880 900 920 940

– – – – – – – – – – – – – – – – – – – – – –

55.7 56.3 56.8 57.3 57.8 58.3 58.8 59.2 59.7 60.1 61.0 61.8 62.5 63.3 64.0 64.7 65.3 65.9 66.4 67.0 67.5 68.0

73.7 74.2 74.6 75.1 75.5 75.9 76.4 76.8 77.2 77.6 78.4 79.1 79.7 80.4 81.1 81.7 82.2 82.7 83.1 83.6 84.0 84.4

Conversions of hardness values using this conversion table are only approximate. See DIN 50 150, December 1976.

Tensile strength

N/mm2

Rm

Brinell hardness1) 1) Calculated from: HB = 0.95 · HV

Diameter of the ball indentation in mm

d

(0.102 F/D2 = 30) D = 10

Hardness value =

Vickers hardness

Diamond pyramid Test forces ≥ 50 N

HV

Rockwell hardness

Ball 1.588 mm (1/16“) Total test force = 98 N

HRB

Diamond cone Total test force = 1471 N

HRC

0.102 · 2 F π D (D – √D2 – d2)

Diamond cone Total test force = 294 N

HB

HR 30 N

47

Temperature Comparison Chart

°C

°F

K

X = particular

K

X– 273

9 /5 (X–273) + 32

X

measured

°C

X

9 /5 X + 32

X + 273

temperature

°F

5 /9 (X–32)

X

5 /9 (X–32) + 273

°C

48

°F

°C

°F

0,00

380,00

716,00

653,15

910,00

1670,00

1183,15

–454,00

3,15

390,00

743,00

663,15

920,00

1688,00

1193,15

–328,00

73,15

400,00

752,00

673,15

930,00

1706,00

1203,15

–150,00

–238,00

123,15

410,00

770,00

683,15

940,00

1724,00

1213,15

–100,00

–148,00

173,15

420,00

788,00

693,15

950,00

1742,00

1223,15

– 90,00

–130,00

183,15

430,00

806,00

703,15

960,00

1760,00

1233,15

– 80,00

–112,00

193,15

440,00

824,00

713,15

970,00

1778,00

1243,15

– 70,00

– 94,00

203,15

450,00

842,00

723,15

980,00

1796,00

1253,15

– 60,00

– 76,00

213,15

460,00

860,00

733,15

990,00

1814,00

1263,15

– 50,00

– 58,00

223,15

470,00

878,00

743,15

1000,00

1832,00

1273,15

– 40,00

– 40,00

233,15

480,00

896,00

753,15

1010,00

1850,00

1283,15

– 30,00

– 22,00

243,15

490,00

914,00

763,15

1020,00

1868,00

1393,15

– 20,00

–

4,00

253,15

500,00

932,00

773,15

1030,00

1886,00

1303,15

– 17,78

0,00

255,37

510,00

950,00

783,15

1040,00

1904,00

1313,15

– 10,00

14,00

263,15

520,00

968,00

793,15

1050,00

1922,00

1323,15

0,00

32,00

273,15

530,00

986,00

803,15

1060,00

1940,00

1333,15

10,00

50,00

283,15

540,00

1004,00

813,15

1070,00

1958,00

1343,15

20,00

68,00

293,15

550,00

1022,00

823,15

1080,00

1976,00

1353,15

30,00

86,00

303,15

560,00

1040,00

833,15

1090,00

1994,00

1363,15

40,00

104,00

313,15

570,00

1058,00

843,15

1100,00

2012,00

1373,15

50,00

122,00

323,15

580,00

1076,00

853,15

1110,00

2030,00

1383,15

60,00

140,00

333,15

590,00

1094,00

863,15

1120,00

2048,00

1393,15

70,00

158,00

343,15

600,00

1112,00

873,15

1130,00

2066,00

1403,15

80,00

176,00

353,15

610,00

1130,00

883,15

1140,00

2084,00

1413,15

90,00

194,00

363,15

620,00

1148,00

893,15

1150,00

2102,00

1423,15

100,00

212,00

373,15

630,00

1166,00

903,15

1160,00

2120,00

1433,15

110,00

230,00

383,15

640,00

1184,00

913,15

1170,00

2138,00

1443,15

120,00

248,00

393,15

650,00

1202,00

923,15

1180,00

2156,00

1453,15

130,00

266,00

403,15

660,00

1220,00

933,15

1190,00

2174,00

1463,15

140,00

284,00

413,15

670,00

1238,00

943,15

1200,00

2192,00

1473,15

150,00

302,00

423,15

680,00

1256,00

953,15

1210,00

2210,00

1483,15

160,00

320,00

433,15

690,00

1274,00

963,15

1220,00

2228,00

1493,15

170,00

338,00

443,15

700,00

1292,00

973,15

1230,00

2246,00

1503,15

180,00

356,00

453,15

710,00

1310,00

983,15

1240,00

2264,00

1513,15

190,00

374,00

463,15

720,00

1328,00

993,15

1250,00

2282,00

1523,15

200,00

392,00

473,15

730,00

1346,00

1003,15

1260,00

2300,00

1533,15

210,00

410,00

483,15

740,00

1364,00

1013,15

1270,00

2318,00

1543,15

220,00

428,00

493,15

750,00

1382,00

1023,15

1280,00

2336,00

1553,15

230,00

446,00

503,15

760,00

1400,00

1033,15

1290,00

2354,00

1563,15

240,00

464,00

513,15

770,00

1418,00

1043,15

1300,00

2372,00

1573,15

250,00

482,00

523,15

780,00

1436,00

1053,15

1310,00

2390,00

1583,15

260,00

500,00

533,15

790,00

1454,00

1063,15

1320,00

2408,00

1593,15

270,00

518,00

543,15

800,00

1472,00

1073,15

1330,00

2426,00

1603,15

280,00

536,00

553,15

810,00

1490,00

1083,15

1340,00

2444,00

1613,15

290,00

554,00

563,15

820,00

1508,00

1093,15

1350,00

2462,00

1623,15

300,00

572,00

573,15

830,00

1526,00

1103,15

1360,00

2480,00

1633,15

310,00

590,00

583,15

840,00

1544,00

1113,15

1370,00

2498,00

1643,15

320,00

608,00

593,15

850,00

1562,00

1123,15

1380,00

2516,00

1653,15

330,00

626,00

603,15

860,00

1580,00

1133,15

1390,00

2234,00

1663,15

340,00

644,00

613,15

870,00

1598,00

1143,15

1400,00

2552,00

1673,15

350,00

662,00

623,15

880,00

1616,00

1153,15

1500,00

2732,00

1783,15

360,00

680,00

633,15

890,00

1634,00

1163,15

2000,00

3632,00

2273,15

370,00

698,00

643,15

900,00

1652,00

1173,15

2500,00

4532,00

2773,15

–273,15

–459,67

–270,00 –200,00

K

K

°C

°F

K

Photos Page

Source

Object/Motif

Cover 03 04 4– 5 4 5

Bavaria Lohmann + Stolterfoth Steinmetz Sauter, Bachmann Sauter, Bachmann Sauter, Bachmann Company photo ATA-GEARS Company photo Steinmetz CarboTech Bavaria Lohmann + Stolterfoth ATA-GEARS Image Bavaria Schreiber/Flender Frese Schuster Bavaria ATA-GEARS Company photo/Flender

Gear wheel Planetary gear Team meeting Spiral bevel gears Set of gears Precision worm Micrograph Hardening of a ring gear Steel bars Chips Cutting drum Hydroelectric power station Planetary gear Spiral bevel gears Drilling rig Wind turbine generators Gears for wind turbine generator Gear wheel Airbus Formula 1 racecar Ring gear with pinion Set of gears

DAF VW Imagine MAAG Gear Company photo Company photo Lohmann + Stolterfoth Company photo/Flender Lohmann + Stolterfoth Company photo Company photo Imagine Company photo/Flender Steinmetz Steinmetz Steinmetz Lohmann + Stolterfoth Company photo Company photo Company photo Company photo Company photo Company photo Company photo Steinmetz Sauter, Bachmann Lohmann + Stolterfoth Lohmann + Stolterfoth ATA-GEARS Frese Lohmann + Stolterfoth Lohmann + Stolterfoth

XF95 truck VW Golf Oil tanker Marine gear Cable car Printing press Parabolic reflector Set of gears Gear wheels for combing cylinder gear Crane truck Wheel loader Ariane rocket Gear detail Sawing of disks Disks with and without drilled hole Steel bars Ground gear wheels Electric arc furnace Continuous casting plant ESR plant Forged steel bars Peeling of steel bars Forging of steel bars Sawing of steel bars Disks with drilled hole Spiral bevel gears Case hardening of a large wheel Ground gear wheels Spiral bevel gears Gear wheel Gear wheels for combing cylinder gear Planetary gear

6– 7 7 7 8 8– 9 8 9

10 10 – 11 10

11

12 12 – 13 12 13

14

15 16 17 18 18 – 19

36 40 42 43 44 48 – 49

50

General note (liability) All statements regarding the properties or utilisation of the materials or products mentioned are for the purposes of description only. Guarantees regarding the existence of certain properties or a certain utilisation are only ever valid if agreed upon in writing.

51

CARBODUR CARBODUR

CARBODUR CARBODUR

CARBODUR CARBODUR Case-hardening steels

• Sales - Case-hardening steels Tel. (+49) 23 02/29 43 46 · Telefax (+49) 23 02/29 46 87 E-mail: [email protected]

EDELSTAHL WITTEN-KREFELD GMBH Auestrasse 4, D-58452 Witten · Tel. (+49) 23 02 / 29 43 07 · Telefax (+49) 2302 / 29 43 08 E-mail: [email protected] · Internet: www.edelstahl-witten-krefeld.de

7/99Ec

• Quality Department Tel. (+49) 23 02/29 40 20 · Telefax (+49) 23 02/29 44 36 Tel. (+49) 21 51/83 20 46 · Telefax (+49) 21 51/83 41 56

Case- hardening steels - SCHMOLZ - BICKENBACH: Sales

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