SS904L and SS316L comparison? and can we use ss904L with Formic Acid and H2SO4

http://www.azom.com/details.asp?articleID=1022

Although originally developed for its resistance to sulphuric acid it also has a very high resistance to a wide range of environments. A PRE of 35 indicates that the material has good resistance to warm sea water and other high chloride environments. High nickel content results in a much better resistance to stress corrosion cracking than the standard austenitic grades. Copper adds resistance to sulphuric and other reducing acids, particularly in the very aggressive "mid concentration" range.

In most environments 904L has a corrosion performance intermediate between the standard austenitic grade 316L and the very highly alloyed 6% molybdenum and similar "super austenitic" grades.

In aggressive nitric acid 904L has less resistance than molybdenum-free grades such as 304L and 310L.