We have an autoclave which seemed to have sprung a leak at a weld. Non-destructive testing was performed, including X-rays, but only potential defects were noticed. We decided to have our welder repair the suspected defects by grinding the them with a non-ferrous tool and re-weld. Unfortunately, the welder HAS used a carbon steel grinding tool to remove the suspect defective weld. He subsequently welded over with stainless steel rods. I believe that pitting or galvanic corrosion will occur. But my question is how to correct it. I do not believe that simple passivation of the weld will solve the problem. Do we need to remove the weld with a nonferrus grinder (more than was originally removed to ensure all contaminents are removed) and re-weld again with stainless steel rods? Or is there a simpler method? Thank you in advance