Characterizations of friction stir welding of dissimilar Monel400 and stainless steel 316

In the present work, the effects of rotating and traverse speeds on the microstructure and mechanical properties of Monel400 and stainless steel 316 joined by friction stir welding were investigated. The employed rotating speed changed from 400 to 600 rpm, whereas the traverse speed varied between 50 and 200 mm/min. Sound welds were obtained at the rotating speed of 400 rpm with the welding speeds of 50 to 100 mm/min, while a groove-like defect was formed when the traverse speed exceeded 150 mm/min. Mechanical properties of the joints were then evaluated using tensile tests and micro-hardness at room temperature. Microstructure evolutions of welds were characterized using optical microscopy and scanning electron microscopy (SEM).