Study of intergranular corrosion of sensitized 304 and 316 stainless steel in sulfocupric medium

The intergranular corrosion of sensitized commercial 304 and 316 stainless steels, using Strauss test in boiling sulfuric acid containing copper and copper sulfide is studied. The effect of sensitization time of alloys in intergranular corrosion phenomena is determined. The role of 2 to 3% molybdenum in the 316 alloy and its effect of the I.G.C. in the medium is also studied. The fracture section and rate of corrosion in stainless steel are observed by electron microscopy and the cause of I.G.C. in such conditions is discussed. The results show that the I.G.C. increases with alloy sensitization and the presence of 3% Mo speeds up this particular type of corrosion