Corrosion Resistance of Welds in Type 316L Stainless Steel

Because of its superior corrosion resistance, austenitic stainless steel series Type 316L (UNS S31603) is a good material for petrochemical industrial equipment. In some weld areas, localized and stress corrosion cracking defects can develop in this material. The major cause of this cracking is precipitation of chromium in austenite grain boundaries. Heat treatment is a common approach to address this problem, but it is not possible for in situ equipment. Research shows that increasing trace elements in weld materials can control chromium precipitation. The effect of different alloy elements on welding properties was investigated for three filler metals. The results show that precipitation of titanium and niobium in the grains can inhibit chromium carbide (Cr C-3 (2)) precipitation and improve cracking resistance and corrosion resistance in sulfur environments.