鋼材摩擦圧接の圧接面における焼付現象の実験的検討 -摩擦圧接の接合メカニズムに関する研究（第5報）-

The present paper describes the seizure phenomena at welded interface during steel pipe friction welding. The relationship between friction speed and initial torque was clarified, and the relationship between relative speed and seizure temperature at the welded interface was estimated from the experimental results. The seizure phenomenon of the base metal was clarified by a constant temperature friction test in which the friction surfaces were rubbed together at various temperatures and loaded pressures in an electric furnace. Then, the seizure temperature at the friction surface was obtained by constant temperature friction tests.The experiments produced the following summarized results.(1) The friction torque curve had wear and seizure stages until the initial torque when pipes were welded at low friction speed. The wear stage time decreased with increasing friction speed. The initial torque decreased with increasing friction speed when pipes were welded at the same friction pressure, and increased with increasing friction pressure.(2) The seizure temperature at the welded interface was calculated by using the relationship between the torsional shear strength of the base metal at its seizure temperature and the measured initial torque. The seizure temperature for a low relative speed at the welded interface was lower than that for a high relative speed.(3) The maximum friction torque increased with increasing friction temperature at the same loaded pressure, and they increased with increasing loaded pressure at the same friction surface temperature by constant temperature friction tests.(4) The friction surface of the base metal began to seize when loaded pressure and friction surface temperature reached or exceeded 30MPa at 423K, and 90MPa at 323K, respectively.