Mechanical Properties and Microstructure of Austenite—Ferrite Duplex Stainless Steel Hybrid (Laser + GMAW) and SAW Welded Joint

Abstract

The purpose of the research was to develop a technology for producing thick-walled duplex steel welded joints. The material used in the research was X2CrNiMoN22 duplex steel in the form of a 15 mm thick plate. The welded joint was produced by the modern, high-performance Hybrid Laser Arc Welding (HLAW) method. The HLAW method involves welding a joint using a laser, the Gas Metal Arc Welding (GMAW) method and the Submerged Arc Welding (SAW) method. The HLAW method was used to make the root pass of the double butt welded joint, while the filler passes were made by the SAW method. The obtained welded joint was subjected to non-destructive and destructive testing. The non-destructive and macroscopic tests allowed the joint to be classified to the quality level B. Microscopic examinations revealed the presence of ferritic–austenitic microstructure in the base material and the weld, with different ferrite content in specific joint areas. The analysed joint had high strength properties (tensile strength (TS) ~ 790 ± 7 MPa) and high ductility of weld metal (~160 ± 4 J) heat-affected zone (~216 ± 26 J), and plasticity (bending angle of 180° with no macrocracks). At the same time, hardness on the cross-section of the welded joint did not exceed 280 HV10.

Effect of Temperature on S32750 Duplex Steel Welded Joint Impact Toughness

“…The mechanical properties and microstructures of austenite-ferrite DSS welded joints made by hybridization (laser and GMAW) and SAW were investigated and presented in [ 22 ], indicating the presence of ferritic-austenitic microstructures both in the BM and WM, as well as high tensile strength (TS) and high ductility of both the WM and HAZ. A similar investigation was performed on laser-welded S32520 DSS, as presented in [ 23 ], indicating that process parameters affected tensile strength in a complex way due to the change in heat energy efficiency with changes in parameters.…”