Stress Corrosion Cracking Behaviour of Welded Duplex Stainless Steel

This study investigated stress corrosion cracking of two welded stainless steel alloys, austenitic 304L and duplex 2205, in an acidic chloride solution. Different heat inputs are selected for welding the alloys, using tungsten inert gas, with and without filler metal. The slow strain rate technique is utilized to estimate the susceptibility of each weldment to stress corrosion cracking. Different strain rates are used, and the experiments showed that the strain rate equal to 1.66x10-6/sec is a critical value that can be used for assessing the susceptibility of the alloys to corrosion cracking. A numerical index used in this study to evaluate this susceptibility, which is based on a ratio between elongation percent of each alloy in the solution to that in the air. The results showed that the austenitic alloy has higher ductility than duplex in air, while there was not a big difference between both alloys in the solution. Increasing the heat input in autogenous welding caused a brittleness, i.e. less elongation, for both alloys. The results showed that the austenitic alloy is exposed to stress corrosion cracking in the solution, before and after welding, with or without filler metals. On the other hand, the duplex alloy showed higher resistance to stress corrosion cracking than the austenitic alloy due to the high chromium content, and it is dual phase.