This study indicated that centrifugally cast 12Cr-4Ni material exhibited hardness values up to HRC 40 in the weld metal in the as-welded condition. Upon post weld heat treatment (PWHT), hardness decreased for all locations with maximum values of HRC 26.5 max. in the weld metal. This was above the HRC 23 max. guidelines for sour service indicated by NACE MR0175 for 12Cr-4Ni materials. Slow strain rate (SSR) teats indicated maximum susceptibility to cracking in the condensed brine (1000 ppm chloride) with hydrogen sulfide at 24 C and only very limited cracking susceptibility in the mixed brine with hydrogen tide at 167 C. Autoclave tests conducted in these environments using stressed beam specimens showed susceptibility to SSC at 24 C in base metal, heat affected zone (HAZ) and weld metal. Maximum susceptibility was in the weld metal producing complete failure in both as-welded and PWHT specimens. The base metal specimens showed lower but still significant susceptibility to SSC. At 167 C, none of the 12Cr-4Ni beam specimens failed showing substantial resistance to SCC.