Corrosion of Weldments J.R. Davis
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We are experiencing severe damage to the SS-316 material piping at the outlet of the sulfuric acid storage vessel. Part I was "Fundamentals of Corrosion". Stress relieving of martensitic or ferritic stainless steel weldments will simultaneously temper weld and heat affected zones, and for most types will restore corrosion resistance to some degree. In it they discuss crevice corrosion as a subset of localized corrosion. It isn't the easiest metal to weld. Being able to weld stainless steel is a great skill for any welder to have because not only does it make a welder very valuable, but some jobs are designed just for welders capable of welding stainless steel. Stainless steel is often used because it is very resistant to both rust and corrosion, thanks to the high levels of chromium contained in it. SX 316 also possesses excellent mechanical and corrosion properties at sub-zero temperatures. PSI produced a document some time ago called "Corrosion and Failure". PWL#039B - Corrosion, Corrosion Prevention, Corrosion Control, Cathodic Protection, SCC and more November 14, 2006. We are using sulfuric acid to maintain the pH of cooling water at our plant. If the flow lines are welded, the operator should be certain that the weldments are at least as corrosion resistant (and where H2S is present, as cracking resistant) as the pipe body. When there is a danger of corrosion in the heat-affected zones of weldments, the low-carbon variety SX 316L should be used. Steel welded to low alloy steel. Encountering any or all of these contaminants can easily lead to localized corrosion or cause weld embrittlement and failure.