248 摩擦圧接の第1位相における接合現象の観察(GS-4 接着・接合・継手)  [in Japanese] 248 Study on joining phenomena in 1st phase of friction welding  [in Japanese]

This report describes the study on joining phenomena in 1st phase of friction welding. Observation of the joining phenomena showed that during the weld faying surfaces rubbed each other, the friction torque was maintained nearly constant. The seizure and the joining occurred at the center portion of them. Then, as they extended from the joint center axis toward the periphery (outer surface), the friction torque increased rapidly. The friction torque reached to the initial peak torque after the welded interface was joined completely, and upsetting of both substrates occurred. It was clarified that the friction time from the friction start (surface contacting) to the initial torque, hereafter called as "elapsed time for initial torque", were variant with the pre-heat at the weld faying surface. The initial torque and the elapsed time for initial torque decreased with increasing the weld faying surface temperature. As a conclusion, the 1st phase can be divided the initial friction part and the seizure part, and the mechanism in the 1st phase of friction welding will be clarify by them.