304 Stainless Steel Composition (SS304 Chemical Composition)

304 stainless steel composition contains 18% chromium and 8% nickel, so it is also known as 18-8 steel. The following table lists the chemical composition of SS304 in various standards.

304 Stainless Steel Composition, %
ASTM Standard	AISI (UNS)	C, ≤	Si, ≤	Mn, ≤	P, ≤	S, ≤	Cr	Ni	N, ≤
ASTM A240/A240M	304 (UNS S30400)	0.07	0.75	2.00	0.045	0.03	17.5-19.5	8.0-10.5	0.1
ASTM A276/A276M		0.08	1.00	2.00	0.045	0.03	18.0-20.0	8.0-11.0	–
ASTM 666; SAE J405		0.08	0.75	2.00	0.045	0.03	18.0-20.0	8.0-10.5	0.1
ASTM A313/A313M		0.08	1.00	2.00	0.045	0.03	18.0-20.0	8.0-10.5	0.1
ASTM A479/A479M		0.08	1.00	2.00	0.045	0.03	18.0-20.0	8.0-10.5	–
ASTM A314; ASTM A580/A580M		0.08	1.00	2.00	0.045	0.03	18.0-20.0	8.0-10.5	0.1
ASTM A473		0.08	1.00	2.00	0.045	0.03	18.0-20.0	8.0-11.0	0.1
ASTM A959		0.07	1.00	2.00	0.045	0.03	17.5-19.5	8.0-11.0	–

Notes:

ASTM A240/A240M: Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip for Pressure Vessels and for General Applications
ASTM A276/A276M: Stainless Steel Bars and Shapes
ASTM A313/A313M: Stainless Steel Spring Wire
ASTM A314: Stainless Steel Billets and Bars for Forging
ASTM A473: Stainless Steel Forgings
ASTM A479/A479M: Stainless Steel Bars and Shapes for Use in Boilers and Other Pressure Vessels
ASTM A580/A580M: Stainless Steel Wire
ASTM 666: Annealed or Cold-Worked Austenitic Stainless Steel Sheet, Strip, Plate, and Flat Bar
ASTM A959: Standard Guide for Specifying Harmonized Standard Grade Compositions for Wrought Stainless Steels
SAE J405: Chemical Composition of SAE Wrought Stainless Steels