Quantitative Analysis of Present Phases in UNS S31803 Duplex Stainless Steel Welded by Conventional Short Circuit MIG/MAG Process

Abstract

The risks involved in materials deterioration and equipment failures due to corrosion associated with mechanical demands are increasing the challenge to search for new materials, alloys, coatings, inhibitors and new design solutions on plants and equipment for better performance and service life. Duplex stainless steel (DSS) has been gaining more and more space because it has many of those requirements mentioned above. High mechanical and corrosion resistance are related to balanced microstructure in approximately 50% ferrite and 50% austenite. In present work, UNS S31803 DSS plates were welded in a 45° bevel by conventional short circuit MIG/MAG process, using three different welding energies at 0.5-0.8 kJ/mm. The results showed that the effect of welding energy on the ferrite volumetric fraction was very marked in the heat affected zone (HAZ) and not so pronounced in the weld metal. Hardness and corrosion resistance (intergranular corrosion) were evaluated as a function of welding energy employed and, in general, both were not influenced when the various welding conditions were compared.

Key-words:
MIG/MAG process; Conventional short-circuit; UNS S31803; Corrosion