40CrMnMo - GB /T 17107-1997

Grade	40CrMnMo
Corresponding Standard	GB /T 17107-1997 Structural Steel Grades And Mechanical Property For Forgings
Classification	Alloy Steel

40CrMnMo Chemical Element Composition Content (%)

Component	C	Si	Mn	P	S	Cr	Ni	Cu	Mo
Minimum Value	0.37	0.17	0.9	-	-	0.9	-	-	0.2
Maximum Value	0.45	0.37	1.2	0.035	0.035	1.2	0.3	0.3	0.3

• High-quality steel——P≤0.035；S≤0.035；Cu≤0.3；Cr≤0.3；Ni≤0.3
• Extra-quality steel （Suffix A）——P≤0.025；S≤0.025；Cu≤0.25；Cr≤0.3；Ni≤0.3
• Special High-Quality Steel (Suffix E)——P≤0.025；S≤0.015；Cu≤0.25；Cr≤0.3；Ni≤0.3

40CrMnMo Mechanical Properties

diameter or thickness d mm	Mark	Heat Treatment or Condition	Tensile Strength σ_b Mpa	Yield Point σ_s Mpa	Elongation or Extension Rate δ %	Reduction of Area ψ %	Impact Energy Absorption KV2 J
d≤100	Sample Direction: Longitudinal	Tempering	≥885	≥735	≥12	≥40	≥39
100＜d≤250	Sample Direction: Longitudinal	Tempering	≥835	≥640	≥12	≥30	≥39
250＜d≤400	Sample Direction: Longitudinal	Tempering	≥785	≥530	≥12	≥40	≥31
400＜d≤500	Sample Direction: Longitudinal	Tempering	≥735	≥480	≥12	≥35	≥23

• The forgings must be inspected for mechanical properties after performance heat treatment and before any surface treatment.
• After the samples are removed, no heat treatments that affect the mechanical properties or any processing that influences the test results shall be conducted.
• Mechanical property testing primarily evaluates the material\'s tensile strength, impact resistance, and hardness. When conducting tensile, impact, and hardness tests simultaneously, the hardness value is for reference only. Alternatively, one may choose to perform only one of the tensile, impact, or hardness tests.

1 Approximate Comparison Table structural alloy steel

China		Japan	South Korea	United States		International Organization for Standardization	Germany		Russia	United Kingdom
GB	ISC	JIS	KS	ASTM/AISI	UNS	ISO	DIN EN/DIN	W-Nr.	GOST	BS EN/BS
40CrMnMo	A34402	SCM440	SCM440	4142 4140	G41420	42CrMo4	42CrMo4	1.7225	40ХГМ	708A42

2 Approximate Comparison Table structural alloy steel

China	United Kingdom
GB	BS EN/BS
40CrMnMo	709M40

40CrMnMo Corresponding Standards(Same grade name, different standards)

1	GB /T 3077-1999
	40CrMnMo A34402
2	GB /T 17107-1997
	40CrMnMo
3	GB /T 3077-2015
	40CrMnMo A34402
4	GJB 1220A-2008
	40CrMnMo
5	GB /T 3078-2019
	40CrMnMo
6	JB /T 6396-2006
	40CrMnMo
7	GB /T 37618-2019
	40CrMnMo A34401

Note: The data is for reference only! If you have any questions, please fill out "I want to correct it"!