Friction stir welding (FSW) is a joining method which uses the frictional heat generation between a rotating tool and joining metals. Wear of the rotating tool decrease the plastic flow of the materials, so that the welding strength will decrease. Therefore, preventing the wear of the rotating tool is an important technology of FSW. Welding of aluminum alloys are the most common FSW process, in that case, the rotating tool materials are tool steels. However, wear properties of steels in the plastic flow of aluminum alloy, such as FSW, is not clear. We carried out the general reciprocating wear test up to 500 °C for carbon steels versus an aluminum alloy. And we analyzed the under structure of wear scar using transmission EBSD, EDS and TEM.
