Y40Mn L20407 - GB /T 8731-2025

Grade	Y40Mn
China ISC	L20407
Corresponding Standard	GB /T 8731-2025 Free-Cutting Structural Steels
Classification	Alloy Steel

Y40Mn Chemical Element Composition Content (%)

Component	C	Si	Mn	P	S
Minimum Value	0.37	-	1.35	-	0.08
Maximum Value	0.45	0.4	1.65	0.04	0.13

Y40Mn Mechanical Properties

diameter d mm	Heat Treatment or Condition	Tensile Strength σ_b Mpa	Specified Plastic Yield Strength Rp_0.2 Mpa	Elongation or Extension Rate δ %	Hardness HBW
d≤20 (Sample Diameter)	Hot Rolled (forged）	550~740			≤225
8＜d≤20 (nominal size)	Cold Drawn	660~880		≥6	186~243
20＜d≤30 (nominal size)	Cold Drawn	625~820		≥6	186~243
d > 30 (nominal size)	Cold Drawn	605~800		≥6	186~243
Bar, Wire Rod①	Quenching at 850-880°C + tempering at 540-680°C②	540~740	≥420	≥14	160~219
Cold Drawn Bar	高温回火	590~785		≥17	179~229

1 Approximate Comparison Table Free-Cutting Structural Steel

China

Taiwan, China

Japan

South Korea

United States

International Organization for Standardization

France

European Standard

Russia

United Kingdom

ISC

CNS

JIS

ASTM/AISI

UNS

ISO

NF EN/NF

Numerical Grade

GOST

BS EN/BS

Y40Mn

L20409

SUM42

1141

G11410

44SMn28

40M5

44SMn28

1.0762

А10Г

212M44

2 Approximate Comparison Table Free-Cutting Structural Steel

China	International Organization for Standardization
GB	ISO
Y40Mn	35SMn20

3 Approximate Comparison Table Free-Cutting Structural Steel

China	International Organization for Standardization	European Standard		Russia
GB	ISO	EN	Numerical Grade	GOST
Y40Mn	44SMn28	44SMn28	1.0762	A40G А40Г

4 Approximate Comparison Table Free-Cutting Structural Steel

China	Japan	United States	International Organization for Standardization	Germany		France	European Standard		Russia	United Kingdom
GB	JIS	ASTM/AISI	ISO	DIN EN/DIN	W-Nr.	NF EN/NF	EN	Numerical Grade	GOST	BS EN/BS
Y40Mn	SUM42	1141 1139	44SMn28 35SMn20	38SMn28	1.0760	38SMn28	38SMn28	1.0760	A40Г	38SMn28

5 Approximate Comparison Table Free-Cutting Steel 1

Y40Mn Corresponding Standards(Same grade name, different standards)

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