Y45MnS U71454 - GB /T 8731-2025

Grade	Y45MnS
China ISC	U71454
Corresponding Standard	GB /T 8731-2025 Free-Cutting Structural Steels
Classification	Carbon Steel

Y45MnS Chemical Element Composition Content (%)

Component	C	Si	Mn	P	S
Minimum Value	0.4	-	1.35	-	0.24
Maximum Value	0.48	0.4	1.65	0.04	0.33

Y45MnS 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）	610~900			≤266
8＜d≤20 (nominal size)	Cold Drawn	695~980		≥6	196~255
20＜d≤30 (nominal size)	Cold Drawn	655~880		≥6	196~255
d > 30 (nominal size)	Cold Drawn	580~880		≥6	196~255
Bar, Wire Rod①	Quenching at 850-880°C + tempering at 540-680°C②	700~850	≥400	≥16	205~252

1 Approximate Comparison Table Free-Cutting Structural Steel

China	Japan	United States	International Organization for Standardization
GB	JIS	ASTM/AISI	ISO
Y45MnS GB/T 8731-2025	SUM43 JIS G4804-2021	1144 ASTM A29/A29M-20	44SMn28 ISO 683-4-2016

Y45MnS Corresponding Standards(Same grade name, different standards)

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