Mechanical and metallurgical analysis of the weld joint between a S32205 duplex stainless steel with ER-385-904L superaustenitic stainless steel filler metal^®

ABSTRACT

The welding of dissimilar steels such as duplex and superaustenitic stainless steels is often used in industrial applications. The effect of welding energy on the heat-affected zone (ZTA) and fusion zone (ZF) presents knowledge gaps to be researched in relation to the metallurgical and mechanical properties of these steels. Variations in the application of welding energy can favor the presence of a greater volume of the ferritic or austenitic phases, and in more critical cases, cause the formation of precipitates harmful to corrosion. This work aims to evaluate the metallurgical, mechanical properties and corrosion resistance of dissimilar welding composed of duplex stainless steel S32205, as base metal, and superaustenitic stainless steel as weld metal, verifying the effects on microstructural, sensitization and anisotropies with the application of different heat inputs. In the microstructural analysis, the formation of first phase constituents, such as grain boundary austenite (GBA), witmanstatten austenite (WA), intragranular austenite (IGA) and secondary austenite (γ2) was verified. The microhardness values found were higher than those reported in the literature. In the corrosion tests, in environments with oxidizing chlorides, the samples showed pitting corrosion, with a high loss of mass in the specimens being detected. It is concluded that in the ZTA the metallurgical characteristics were maintained after the variation of the thermal input and in the ZF there was an increase in the loss of mass in the corrosion test in the analyzed samples.

Keywords
Duplex stainless steel; Superaustenitic stainless steel; Welding