What is the difference between SS304 and SS316?

304 is a low carbon modification of 302 SST (which is the general purpose austenitic or 18-8 SST) for restriction of carbide precipitation during welding. 304L is a lower carbon modification of 304 for further restriction of carbide precipitation during welding. Max carbon in 304 is 0.08 versus 0.15 in 302 and 0.03 in 304L. 316 is more corrosion resistant than 302 and 304, with higher creep strength, primarily due to the higher Nickel content. 316L is again primarily used for welded construction. 316 has the same carbon content as 304 and 316L as 304L. 302 304 304L 316 316L Cr 17/19 18/20 18/20 16/18 16/18 Ni 8/10 8/12 8/12 10/14 10/14 C max 0.15 0.08 0.03 0.08 0.03 Mn max 2.0 2.0 2.0 2.0 2.0 Si max 1.0 1.0 1.0 1.0 1.0 P max .045 .045 .045 .045 .045 S max .03 .03 .03 .03 .03 Other - - - Mo 2.0/3.0 316L can be used in place of 316 in all applications but the reverse is not true. 316L should be used for welded structures requiring high corrosion resistance. 316L is more expensive than 316 in most regions of the world.