An extensive analysis of GTAW process and its influence on the microstructure and mechanical properties of SDSS 2507

Abstract

The Gas Tungsten Arc Welding (GTAW) process is well-known for its accuracy, simplicity, and economical, making it the optimum method for joining Super Duplex Stainless Steel (SDSS) materials. This review paper investigates the influence of the GTAW process on the microstructure, tensile strength, micro-hardness and corrosion resistance of SDSS welded joints. The optimum constant current GTAW process parameters are discovered by various researchers who found that the welding current range should be 65A–160A for joining up to 6 mm thick SDSS material. The pulsed current GTAW process optimum Peak current range (120–165A) and back current (60–80A) range for joining 4–14 mm thick SDSS material. Microstructural analysis revealed that coarse grain is in the welded joint's weld zone (WZ) and heat-affected zone (HAZ) because of the weld thermal cycle. The Widmanstatten austenite with ferrite grain boundary is found between HAZ and WZ due to thermal cooling. Welded joint tensile strength (740 MPa–896 MPa) is sometimes greater or the same as the base metal. It shows the GTAW best parameters selection. The microhardness of HAZ (380 HV) and WZ (370 HV) of the welded joint is increased with respect to base metal (310HV) GTAW process. Multiple studies have shown that using the best GTAW parameters can improve the microstructural properties of SDSS, resulting in increased tensile strength. The charge transfer resistance analysis of GTAW welded joint revealed that higher charge transfer leads to a lower corrosion rate having ER2594 filler material with icorrs value of 0.0139 μA/cm2.

Keywords

• Gas tungsten arc welding
• Super duplex stainless Steel
• Microstructure
• Tensile test
• Micro-harness