Effect of metallurgical variables on the stress corrosion crack growth behaviour of AISI type 316LN stainless steel

Mill-annealed AISI type 316LN stainless steels, received from two different sources (one indigenous (SS-2) and the other foreign (SS-1)), were tested for stress corrosion cracking (SCC) resistance in a boiling acidified environment of NaCl. SCC results indicated a remarkably lower value of plateau crack growth rate (PCGR) and higher values of KISCC and JISCC for SS-2, which was attributed to the lower effective grain boundary energy resulting from a higher amount of copper in it. Cold working reduced KISCC and PCGR; while thermal aging and welding decreased KISCC and increased PCGR vis-à-vis the annealed material.