The key difference between 304 vs 316 stainless steel is the addition of molybdenum, an element that drastically enhances corrosion resistance, especially for more saline or chloride-exposed environments. 316 stainless steel contains molybdenum, but 304 does not.
Cast alloys
CF8M (316 equivalent)
What is CF8M and why is it magnetic?
Although ASTM grade CF8M and AISI 316 are both austenitic stainless steels, AISI 316 is nonmagnetic because it is essentially austenite. Cast 316 or CF8M is slightly magnetic because it is not entirely austenite and contains from 5 – 20 percent ferrite. By reducing or eliminating the quantity of ferrite in the chemical composition, wrought material manufacturers are able to make an alloy that is easier to roll into sheets or bars. Cast material manufacturers do not have the same requirements and therefore, can use a slightly harder alloy that contains ferrite. The inclusion or ferrite provides increased resistance to stress corrosion cracking and cracking during welding or casting.
