4140
Chromium-Molybdenum Steel
- Supplied in the annealed or
prehardened condition.
- The prehardened condition is heat
treated to a medium hardness (HRC 28/32) and is designated as 4140
HT.
- 4140 annealed is supplied in the
soft condition and can be hardened to RC 54.
- 4140 HT is supplied in many forms
such as hot rolled or turned, ground and polished rounds
and DCF plate to be used as a holder material for high
strength structural components.
Composition
Element
Weight %
C
0.38-0.43
Mn
0.75-1.00
P
0.035 (max)
S
0.04 (max)
Si
0.15-0.30
Cr
0.80-1.10
Mo
0.15-0.25
Mechanical
Properties
Hot Rolled:
Typical Tensile Strength:
89 KSI
Typical Yield Strength:
62 KSI
Cold Rolled:
Typical Tensile Strength:
102 KSI
Typical Yield Strength: 90 KSI
Oil Quenched & Tempered:
Typical Tensile Strength:
153 KSI
Typical Yield Strength: 131 KSI
Designations
France:
AFNOR 40 CD 4 , AFNOR 42 CD 4
Germany: DIN 1.7225
Italy: UNI 38 CrMo 4 KB ,
UNI 40 CrMo 4 , UNI G 4O CrMo 4
Japan: JIS SCM 4 , JIS
SCM 4 H
Sweden: SS 2244
United Kingdom: B.S. 708
A 42 , B.S. 708 M 40 , B.S. 709 M
40
United States: AMS 6378 ,
AMS 6379 , AMS 6381B , AMS 6382 ,
AMS 6382G , AMS 6390 , AMS 6390A , AMS 6395 , ASTM A322 , ASTM A331 ,
ASTM A505
, ASTM A519 , ASTM A547 , ASTM A646 , MIL SPEC MIL-S-16974 , SAE J404 ,
SAE
J412 , SAE J770 , UNS G41400
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