s355mc vs s355jr

Sorry, I'm new in material zone so i mistyped the material grades then question should be "in what conditions S355 J0 instead of S355 J2?" ThanksThe main difference between structural steel grade S355 J2 and JO is that at the notch impact test (longitudinal ) : JO : absorbs energy min. 27 J at temperature 0 C J2 : absorbs energy min. 27 J at temperature -20 C So it concerns impact behaviour at different temperatures. If -20 C temperature is out of every probability in the particular use of the steel then choice of S355J0 is OK. In both cases however the price ( cost of steel ) is almost the same.Does it mean JO can be upgrade and acceptable if i can do longitudinal -20 degree impact test ? Another question is about the chemical compositions. for JO materials P, S values should be max 0,030 and N need to be 0,015 but for J2 P, S values are 0,025 and there isnt N ?As for P,S values are more like J0- P,S : 0,040 percent N : 0,015 ( all maximum ) J2- P,S : 0,035 " N : no ( for long products P and S may be 0,005 more ). All those qunatities are actually very small, so you should estimate if they are a concern at all for your application ( most probably they are not - this quality being conventional construction oriented. )