20Г - GOST 4543-1971

Grade	20Г
Corresponding Standard	GOST 4543-1971 Alloyed Construction Steel Specifications
Classification	Alloy Steel
Properties	High Hardenability

20Г Chemical Element Composition Content (%)

Component	C	Si	Mn	P	S	Cr	Ni	Cu
Minimum Value	0.17	0.17	0.7	-	-	-	-	-
Maximum Value	0.24	0.37	1	0.035	0.035	0.3	0.3	0.3

• The letter A at the end of the grade stands for “high quality steel”. Character III means “Extra high quality steel”. For example, quality steel -30XΓC; High quality steel -30XΓCA; Extra high quality steel -30X ΓC-Ⅲ and 30XΓCA-Ⅲ.

20Г Mechanical Properties

diameter(thickness) d(t) mm	Tensile Strength σ_b Mpa	Yield Point σ_s Mpa	Elongation or Extension Rate δ %	Hardness HBW
d≤25	Quenching + Tempering ≥450	Quenching + Tempering ≥275	Quenching + Tempering ≥24	HB ≤179

• d=circle diameter or quadrate side，unit mm
• Mechanical properties suitable for diameter or thickness less than or equal to 80mm, other sizes of mechanical properties requirements see the standard original.
• The impact test shall comply with GOST 9454-78.
• If the yield phenomenon is not obvious and the yield stress σT(i.e., σs) cannot be determined, the yield limit σ0.2(i.e., Rp0.2) is allowed.
• Allowable deviation of heat treatment temperature: quenching ±15°C; Low temperature tempering ±30°C; High temperature tempering ±50°C

1 Approximate Comparison Table High-Quality Carbon Structural Steel

China		United States		Germany		France	Russia	Sweden	United Kingdom
GB	ISC	ASTM/AISI	UNS	DIN EN/DIN	W-Nr.	NF EN/NF	GOST	SS	BS EN/BS
20Mn	U21202	1022	G10220	21Mn4	1.0470	20M5	20г	1434	080A20

2 Approximate Comparison Table Structural Alloy Steel

China		Taiwan, China	Japan	South Korea	United States	International Organization for Standardization	Germany		France	Russia	United Kingdom
GB	ISC	CNS	JIS	KS	ASTM/AISI	ISO	DIN EN/DIN	W-Nr.	NF EN/NF	GOST	BS EN/BS
20Mn2	A00202	SMn420	SMn420	SMn420	1320 1524	22Mn6	20Mn6	1.1169	20M5	20Г2 20Г	150M19

3 Approximate Comparison Table High-Quality Carbon Structural Steel

China	Japan	United States	Germany		France	Russia	United Kingdom
GB	JIS	ASTM/AISI	DIN EN/DIN	W-Nr.	NF EN/NF	GOST	BS EN/BS
20Mn (GB/T 699-1999)	SWRCH22K	1019 1022	C22	1.0402	XC18 C22	20Г	080A20 080A22 C22

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