Bude
rus
Plas
tic
Mou
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teel
273
8 IS
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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 [email protected] 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
Lega
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Bud
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Ede
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Bud
erus
Ede
lsta
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dis
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ll lia
bilit
y fo
r los
s or d
amag
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any
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clud
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Thi
s pu
blic
atio
n su
pers
edes
all
prev
ious
one
s. ©
Bud
erus
Ede
lsta
hl G
mbH
, Wet
zlar
, 03/
2015
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)
