Metallurgical Analysis to Evaluate Cracking in a 316L Grade Stainless Steel Spiral Heat Exchanger
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A spiral heat exchanger (SHE) constructed of Grade 316L stainless steel developed a leak after 8 years of service as a condenser on a distillation tower. Examination of the SHE identified the leak as being located on the cooling water side in the heat affected zone (HAZ) of a weld joining two plates. Cooling water deposits were observed in a V-shaped corner formed by the weld. A metallurgical examination identified the presence of transgranular cracks at the HAZ on the cooling water side. Analysis of the cooling water revealed the presence of chlorides. Based on the metallurgical analysis and the presence of chlorides, it was determined that the cracks and resulting leak were the result of chloride stress corrosion cracking.
Keywords316L stainless steel Spiral heat exchanger Chloride stress corrosion cracking
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