ML42CrMo A30424 - GB T 6478-2001

Grade	ML42CrMo
China ISC	A30424
Corresponding Standard	GB T 6478-2001 Steels for cold heading and cold extruding
Classification	Alloy Steel

ML42CrMo Chemical Element Composition Content (%)

Component	C	Si	Mn	P	S	Cr	Ni ^*	Cu ^*	Mo
Minimum Value	0.38	-	0.6	-	-	0.9	-	-	0.15
Maximum Value	0.45	0.3	0.9	0.035	0.035	1.2	0.2	0.2	0.25

①By agreement between the supplier and the purchaser, other grades of cold heading and cold extrusion steel may be supplied.
②Permissible deviations in the chemical composition of the steel shall comply with the relevant provisions of GB/T 222-1984.

ML42CrMo Mechanical Properties

condition	Heat Treatment or Condition	Tensile Strength σ_b Mpa	Yield Point σ_s Mpa	Elongation or Extension Rate δ %	Reduction of Area ψ %
Sample diameter d=25	Quenching temperature 830~870°C, oil quenching, tempering temperature 500~600°C	≥1080	≥930	≥12	≥45

New and Old Grade Replacement List

Corresponding Standard	Grade
GB T 6478-2001	Grade China ISC
GB /T 6478-2015	Grade China ISC Old Grade

1 Approximate Comparison Table Cold Heading Steel

China		United States		International Organization for Standardization	Germany		France
GB	ISC	ASTM/AISI	UNS	ISO	DIN EN/DIN	W-Nr.	NF EN/NF
ML42CrMo	A30424	4140 A320ML7M	G41400	42CrMo4E (C32)	42CrMo4	1.7225	42CD4

2 Approximate Comparison Table Steel for Cold Heading and Cold Extrusion

China	Japan	United States	International Organization for Standardization	Germany
GB	JIS	ASTM/AISI	ISO	DIN EN/DIN
ML42CrMo	SCM440	4140	42CrMo4E	42CrMo4

ML42CrMo Corresponding Standards(Same grade name, different standards)

1	GB T 6478-2001
	ML42CrMo A30424
2	GB /T 6478-2015
	(ML42CrMo) ML40CrMo A30404
3	Q/BQB 517-2018
	ML42CrMo
4	GB /T 5953.1-2009
	ML42CrMo
5	GB /T 28906-2025
	ML42CrMo

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