Effect of Various Conditions on Friction Torque in the First Phase of Friction Welding - Study of Joining Mechanism of Friction Welding (Report 2) -

In the previous report 1, the authors have clarified the joining mechanism of the first phase of friction stage during friction welding process. The present paper describes the effects of various conditions on friction torque in the first phase during friction stage for joining of carbon steels. The various conditions included friction pressure, friction speed, weld faying surface diameter and yield strength properties of both substrates, and per-heat of them. The following are concluded. (1) The initial torque and the elapsed time for initial torque to it were affected by friction pressures and friction speeds described above for joining of same yield strength properties and weld faying surface diameter substrates. That is, the initial torque increased with increasing the friction pressure and it decreased with increasing the friction speed, and the elapsed time for initial torque decreased with increasing the friction pressure and the friction speed. (2) In spite of the weld faying surface diameter in both substrates, the initial torque and the elapsed time for initial torque hardly changed. (3) In spite of the yield strength property in both substrates, the initial torque and the elapsed time for initial torque hardly changed. (4) The initial torque and the elapsed time for intial torque decreased with increasing of pre-heat temperature.Especially,the wear stage rapidly decreased when pre-heat temperature exceeded approximately 473K (200℃)