Failure analysis of a welded 316L stainless-steel stack with premature damage due to stress-corrosion cracking

Abstract

Abstract This study analyzed the premature failure of a stainless-steel stack obtained from a mining company. The stack was manufactured using ASTM A240 Type 316L stainless steel. After one year of its service, massive leakages and cracks were observed near the welds. Following a visual examination of the stack, a representative sample was extracted and analyzed using visual and radiographic inspection, metallographic examination, scanning electron microscopy, energy dispersive spectrometry, optical emission spectrometry, ferrite number analysis, and leak testing. Furthermore, corrosion mechanisms and the sequence of events leading to failure were determined. Two different mechanisms were identified: acid dew point corrosion caused by the condensation of H2SO4 and HCl at the inner walls of the chimney, followed by stress-corrosion cracking near the welded joints.