Effect of fixed location variation in friction stir welding of steels with different carbon contents

Dissimilar friction stir welding between steels with different carbon contents was carried out by placing the parent materials at two different fixed locations: the advancing side (AS) and the retreating side (RS). The phase transformation and the depth and width of the weld were affected by the fixed location. A smaller weld nugget was formed, and more martensite transformation occurred when the stronger SK5 steel was fixed at AS, compared to that at RS. This variation was attributed to the difference of temperature and materials flow between AS and RS.