Y12 U71121 - GB /T 8731-2025

Grade	Y12
China ISC	U71121
Corresponding Standard	GB /T 8731-2025 Free-Cutting Structural Steels
Classification	Carbon Steel

Y12 Chemical Element Composition Content (%)

Component	C	Si	Mn	P	S
Minimum Value	0.08	-	0.7	0.08	0.1
Maximum Value	0.16	0.4	1	0.15	0.2

Y12 Mechanical Properties

diameter d mm	Heat Treatment or Condition	Tensile Strength σ_b Mpa	Elongation or Extension Rate δ %	Hardness HBW
d≤20 (Sample Diameter)	Hot Rolled (forged）	350~530		≤156
8＜d≤20 (nominal size)	Cold Drawn	530~755	≥7	152~217
20＜d≤30 (nominal size)	Cold Drawn	510~735	≥7	152~217
d > 30 (nominal size)	Cold Drawn	490~685	≥7	152~217

New and Old Grade Replacement List

1 Approximate Comparison Table Free-Cutting Structural Steel

China		Taiwan, China	Japan	South Korea	United States	International Organization for Standardization	Germany		France	Russia
GB	ISC	CNS	JIS	KS	ASTM/AISI	ISO	DIN EN/DIN	W-Nr.	NF EN/NF	GOST
Y12	U71122	SUM21	SUM21	SUM21	B1112 1211①	10S20	10S20	1.0721	13MF4	А12

2 Approximate Comparison Table Free-Cutting Structural Steel

3 Approximate Comparison Table Free-Cutting Structural Steel

China		Japan	United States	International Organization for Standardization	Russia
GB	ISC	JIS	ASTM/AISI	ISO	GOST
Y12	U71122	SUM12	1211 1212	10S20	A12

4 Approximate Comparison Table High-Quality Carbon Structural Steel

Y12 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"!