L7M L70 - ASTM A 320-2000

AISI American Iron and Steel Institute	4140
ASTM Specification or Grade	L7
Other Names
Corresponding Standard	ASTM A 320-2000 Standard Specification for Alloy-Steel and Stainless Steel Bolting Materials for Low-Temperature Service
Classification	Alloy Steel
Properties	High Strength High Hardenability

Chemical Element Composition Content (%)

Component	C	Si	Mn	P	S	Cr	Mo
Minimum Value	0.38	0.15	0.75	-	-	0.8	0.15
Maximum Value	0.43	0.35	1	0.035	0.04	1.1	0.25

Mechanical Properties

diameter（grade） d mm	Heat Treatment or Condition	Tensile Strength σ_b Mpa	Yield Point σ_s Mpa	Elongation or Extension Rate δ %
d≤65(L7、L70)	Quenching + Tempering	≥860	≥725	≥16
d≤65(L7M)		≥690	≥550

1 Approximate Comparison Table Alloy Steel for Quenching and Tempering

United States	International Organization for Standardization	Germany	France	European Standard
ASTM	ISO	DIN EN/DIN	NF EN/NF	EN	Numerical Grade
4140	42CrMoS4	42CrMoS4	42CD4u	42CrMoS4	1.7227

2 Approximate Comparison Table Structural Alloy Steel

China	Japan	United States	International Organization for Standardization	Germany	France	European Standard		Russia	Sweden	United Kingdom
GB	JIS	ASTM	ISO	DIN EN/DIN	NF EN/NF	EN	Numerical Grade	GOST	SS	BS EN/BS
42CrMo	SCM440H	4140 4142	42CrMo4	42CrMo4	42CD4	42CrMo4	1.7225	35KHM 38KHM	2244	708M40 CFS11

3 Approximate Comparison Table Structural Alloy Steel

4 Approximate Comparison Table Steel for Cold Heading and Cold Extrusion

China	Japan	United States	International Organization for Standardization	European Standard
GB	JIS	ASTM	ISO	EN
ML40CrMo	SCM440	4140	42CrMo4	42CrMo4

5 Approximate Comparison Table Steel for Cold Heading and Cold Extrusion

China		Japan	United States	International Organization for Standardization	European Standard
YB	GB	JIS	ASTM	ISO	EN
QML40CrMo	ML40CrMo	SCM440	4140	42CrMo4	42CrMo4

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