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Buderus Edelstahl GmbH l Steel Bar Sales l Buderusstraße 25 l D-35576 WetzlarTelephone +49 (0) 64 41-374 2468 l Fax +49 (0) 64 41-374 2784 l info@buderus-steel.com l www.buderus-steel.

C Si Mn P S Cr Ni MoTypical analysis 0.36 0.30 1.50 0.020 0.003 2.00 1.00 0.20

Chemical composition as per SEL

0.35–0.45

0.20–0.40

1.30–1.60

≤0.030

≤0.030

1.80–2.10

0.90–1.20

0.15–0.25

Figures in % by mass

Register of European Steels (SEL)

40 CrMnNiMo 8-6-4

DIN EN ISO 4957 40 CrMnNiMo 8-6-4

AFNOR 40 CMND 8

AISI ~ P 20 + Ni

BS ~ P 20 + Ni

CharacteristicsMould steel for large dimensions > 400 mm thick. Properties as for grade 2311 ISO-BM, but with improved through-hardening.Nitridable, hard chrome plateable, flame hardenable, polishable, grain-reliable as delivered.

In an extreme dimensional range, and where there is a requirement for l Higher hardness and better through-hardenability l Polishability > 320 grit l Sensitive etch-graining designs (e.g. HNO3) l Higher thermal conductivitywe recommend grade 2738mod.TS(HH).

ApplicationsTools for compression and injection moulds, bumpers, dashboards, chairs, rubbish bins, bottle crates, television cabinets, etc.

Diecasting mould frames: The material is hardened and tempered as forged steel bar in production lengths. Due to the restricted through-hardenability of the grade 2738 ISO-BM, please note that there may be a mixed grain structure at the front surface when sawing to individual lengths. If this is not desired, we recommend using Thruhard Supreme® 2738mod.TS (280 – 325 HB), orThruhard Supreme® 2738mod.TS(HH) (310 – 355 HB)for bar thicknesses > 600 mm.

Delivered conditionQuenched and tempered to 280–325 HB (≙ approx. 950–1100 MPa)*

Physical properties (reference values)Thermal expansion coefficient (10–6/K)

20–100 °C11.6

20–250 °C12.8

20–500 °C14.3

Thermal conductivity(W/mK)

20 °C34.0

250 °C33.5

500 °C33.0

Young’s modulus (GPa)

20 °C212

250 °C197

500 °C175

l Buderus Plastic Mould Steel 2738 ISO-BM

* Surface hardness in Brinell, converted to DIN EN ISO 18265, Table A.1; we offer no quality guarantee with higher hardness requirements

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Heat treatment

Stress relieving Temperature: Approx. 600 °C in the annealed stateApprox. 550 °C in the quenched and tempered state

Duration: 1 hour per 50 mm wall thicknessCooling: Furnace

Soft annealing Temperature: 720 °CDuration: 1 hour per 25 mm wall thicknessCooling: Furnace

Hardening Temperature: 880 °CDuration: 1 minute per mm wall thickness

Quenching hardness Max. 54 HRC in oil, hot bath or vacuum

Tempering Temperature: See tempering curveDuration: 1 hour per 25 mm wall thicknessCooling: Air

Working hardness 280–325 HB

Tempering curve

TTT curve (continuous)

l 2738 ISO-BM

343638404244464850525456

0 100 200 300 400 500 600 700 800

5860

354373392413436

HB

(461)

337

Har

dnes

s in

HRC

Tempering temperature in °C

Average values on samples dia. 25 x 50 mm hardened at 880 °C in oilHB converted from HRC

100

200

300

400

500

600

700

800

900

1000

1100

1200

01 10 102 103 104 105 106

1 10 100 1000 10 000

650 657 642657 514608 420 311707 707 707 705 710 642

Tem

pera

ture

in °

C

Time

Seconds

Minutes

Austenitising temperature: 880

Ac3

Ac1

P

Mf

Ms B

F

25

26

27

28

29

30

31

32

200 400 600 800 1000 1200 1400

33

34

35

Core

har

dnes

s in

HRC

Diameter in mm

Surface hardness = 31 HRC

THRUHARD SUPREME®

Surface hardness = 31 HRC

Surface hardness = 35 HRC

THRUHARD

Surface hardness = 31 HRC

2738

2311

Through-hardenability (schematic)