A novel plate joining method was proposed by one of the authors.It makes use of the thermally activated cut faces obtained by high-speed shear.The joining process is illustrated in Fig.1 [1].A pair of metal plates to be joined is simultaneously sheared along the dotted line under high-speed condition.The material temperature elevates remarkably and it softens in the adiabatic shear band.The lower plate is stationary.The upper plate continues the downward motion,thus the cut face of the upper plate immediately contacts the lower cut face with slight overlap.The joining process is completed when the upper plate reaches the prescribed position.The present joining method is a kind of diffusion bonding which is known as solid-state welding technique.