Corrosion and Mechanical Properties of the Recently Developed Super Duplex Stainless Steel UNS S83071 Welded Using Different Filler Metals

Abstract UNS S83071 is a recently developed super duplex stainless steel (SDSS) optimized for general corrosion resistance. The composition is 30Cr-7Ni-3.5Mo-N. The material is characterized by excellent acid and caustic corrosion resistance with the traditional benefits of SDSSs, such as excellent resistance to pitting, crevice corrosion, and stress corrosion cracking. In many applications where UNS S83071 is used, welding is often required, particularly in the fabrication of heat exchangers where tube-to-tubesheet welding is standard. It is therefore important to have good knowledge of the mechanical and corrosion properties of the welded joints. This paper presents the results of corrosion and mechanical testing of welded UNS S83071 tubes, using two different filler metals: W Z 29 8 2 L (super duplex) and W Z 27 7 5 L (hyper duplex). The welding was performed using manual gas tungsten arc welding (GTAW) method. The corrosion resistance of the weldments was evaluated by pitting corrosion testing and general corrosion testing in acidic environments. The mechanical properties were assessed in accordance with ASME section IX. Additionally, the microstructure of the weldments was examined. The investigation provides valuable insights into the performance of welded UNS S83071.