Abstract: A spot friction welding tool is for performing spot friction welding of a first member and a second member by superposing the first member and the second member and pressing the spot friction welding tool against the first member and the second member from the first member side. Each of the first member and the second member is a steel plate having a tensile strength of not lower than 590 MPa. The spot friction welding tool is rotatable around a rotation axis. The spot friction welding tool includes a column having a shoulder at a tip end thereof, and a cylindrical or truncated conical probe protruding from the shoulder in a direction of extension of the rotation axis.

Abstract: A spot friction welding tool is for performing spot friction welding of a first member and a second member by superposing the first member and the second member and pressing the spot friction welding tool against the first member and the second member from the first member side. Each of the first member and the second member is a steel plate having a tensile strength of not lower than 270 MPa and not higher than 370 MPa. The spot friction welding tool is rotatable around a rotation axis. The spot friction welding tool includes a column having a shoulder at a tip end thereof, and a cylindrical or truncated conical probe protruding from the shoulder in a direction of extension of the rotation axis.

Abstract: There is provided a tool for friction stir welding, in which a coating layer is less likely to peel off from a base material and excellent wear resistance is achieved. The tool for friction stir welding according to the present invention includes a base material (BM) and a coating layer. The BM includes a first hard phase (FP) formed by WC particles, a second hard phase (SP) and a binder phase (BP). The SP is formed by a compound of one or more metals selected from Ti, Zr, Hf, Nb, Ta, Cr, Mo, and W and one or more elements selected from nitrogen, carbon, boron, and oxygen, and is included in the BM at a volume ratio of 3% to 30%. The BP is included in the BM at a volume ratio of 8% to 28%. The FP is higher than the SP in terms of volume ratio.

Abstract: There is provided a tool for friction stir welding having excellent wear resistance and chipping resistance. The tool for friction stir welding according to the present invention includes a base material, the base material includes a first hard phase, a second hard phase and a binder phase, the first hard phase is formed by WC particles, the second hard phase is formed by a compound of one or more metals selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, and W and one or more elements selected from the group consisting of nitrogen, carbon, boron, and oxygen, or a solid solution of the compound (except for WC), the binder phase is formed by an iron group metal, and the second hard phase is higher than or identical to the first hard phase in terms of volume ratio.