Study of solidification behaviour and mechanical properties of arc stud welded AISI 316L stainless steel

Abstract

Purpose: This paper aims to investigate the impact of arc stud welding (ASW) process parameters on the microstructure and mechanical properties of AISI 316L stainless steel stud/plate joint. Design/methodology/approach: The weld performed using ASW machine. The influence of welding current and time on solidification mode and microstructure of the fusion zone (FZ) was investigated using optical microscope and scanning electron microscope (SEM). Microhardness and torque strength tests were utilised to evaluate the mechanical properties of the welding joint. Findings: The results showed that different solidification modes and microstructure were developed in the FZ. At 400 and 600 A welding currents with 0.2 s welding time, FZ microstructure characterised with single phase austenite or austenite as a primary phase. While with 800 A and 0.2 s, the microstructure consisted of ferrite as a primary phase. Highest hardness and maximum torque strength were recorded with 800 A. Solidification cracking was detected in the FZ at fully austenitic microstructure region. Research limitations/implications: The main challenge in this work was how to avoid the arc blow phenomenon, which is necessary to generate above 300 A. The formation of arc blow can affect negatively on mechanical and metallurgical properties of the weld. Practical implications: ASW of austenitic stainless steel are used in multiple industrial sectors such as heat exchangers, boilers, furnace, exhaust of nuclear power plant. Thus, controlling of solidification modes plays an important role in enhancing weld properties. Originality/value: Study the influence of welding current and time of ASW process on solidification modes, microstructure and mechanical properties of AISI 316 austenitic stainless steel stud/plate joint.