Stress corrosion cracking is very complex problem, because it involve stress, corrosion environment and material. It is almost impossible to write the whole explanation only in few lines, so I'll give you a list of references:
Russel H. Jones, Stress-Corrosion Cracking, ASM international, this...
Very well polished surface have good corrosion resistence. But the inclusions in stainless steels can produce powerful micro galvanic cells in presence of corrosion medium. It will be reasonable to use better grades of stainless steels like AISI 304L or AISI 316L.
