The tensile strength measurement indicated that the strength was directly proportional to the weld speed and tool rotation speed. Measurement of tensile strength revealed that the strength was maximum when the weld speed and tool rotation speed was maximum. However it was noticed that for different tool rotation the maximum of the microhardness was obtained for 350 rpm. It was identified that for a given tool rotation speed, the microhardness increased proportionally with respect to the weld speed and depth along the joint. The prepared joints were tested in order to analyze its microhardness, tensile strength, temperature distribution, force and microstructure along the joint. Six joints were made using the combination of three tool rotation speed 350 rpm, 550 rpm and 900 rpm and three weld traverse speed 55 mm/min, 100 mm/min, 110 mm/min. AA6061 plates of 6mm thick each were joined through butt welding configuration by Friction Stir Welding process using a CNC milling machine and a non consumable tool with square pin profile. Many research activities have been conducted on this metal joining processes which lead to the process being used in diverse field of applications. The best solution based on the mechanical, microstructural, and fracture analysis concluded that TIG welding with MS filler rod and PWHT at 600 ☌ is the optimum condition for joining SS AISI 304 with MS AISI 1020.įriction Stir Welding is a versatile metal joining process, which has been adopted to join composite materials. After conducting fracture analysis by SEM, it has been noticed the specimen becomes more ductile after PWHT. The hardness values have decreased after PWHT which justified the achievement of higher ductility after heat treatment. This is the region where the hardness values were the smallest. The coarser grain structure was observed in the heat-affected zone (HAZ) which makes the sample susceptible to failure. Both optical and SEM micrographs showed that the amount of δferrite and martensite is higher in the as-welded situation. Destructive tests have suggested that PWHT at 630 ☌ is better for the SMAW process with both MS and SS electrodes and PWHT at 600 ☌ is more suitable for TIG welding process with both MS and SS filler rod. To explore the optimum welding process and PWHT process for this dissimilar joint, both tensile and bending tests were carried out.
For post-weld heat treatment (PWHT), three distinct temperatures of 600 ☌, 630 ☌, and 650 ☌ were investigated over the welded specimens.
To investigate the effect of filler material in the dissimilar welding joint, both MS and SS filler material was exercised. In this research, the welding joint between stainless steel (SS) of grade AISI 304 and mild steel (MS) of grade AISI 1020, was accomplished by using shielded metal arc welding (SMAW) and tungsten inert gas (TIG) welding process. Joining of two materials having different physical, chemical, and thermal properties and to make the joint tough and stiff, special attention and investigation are required.
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