Study on the Corrosion Behavior of Austenitic Stainless Steel Piping in Ships with TIG Automatic Welding

Abstract

To study the corrosion behavior of welded parts in marine pipeline systems，316L austenitic stainless steel joints were welded using all-position TIG automatic welding technology.These joints were tested by tensile，bending and macroscopic metallographic tests，as well as corrosion depth，surface morphology and micro-electrochemical tests after accelerated corrosion tests.The effect of the welding process on the mechanical properties and corrosion behavior of the specimens was investigated.Through welding tests and inspections，it was found that by altering the design of the welding parameters for different zones，the welding quality of the welded joint could be effectively guaranteed，and the mechanical properties of the welded joint were qualified.Results on the corrosion behavior of stainless steel pipes after welding under this welding process showed that in the simulated salt spray humid heat/SO2 atmosphere，corrosion of the welded materials was primarily localized as pitting corrosion，and the corrosion products were clumped.As the corrosion process continued，these products grew and connected to each other，forming a complete rust layer.This layer had a protective effect on the substrate，thereby delaying corrosion from penetrating into the substrate.Corrosion was preferentially observed in the heat-affected zone.As the corrosion cycle prolonged，the corrosion resistance of the sample’s base metal zone consistently remained higher than that of the heat-affected zone.

Keywords

• 316l stainless steel|pitting corrosion|mechanical properties|micro region electrochemistry