METHOD FOR QUENCHING AFTER CARBURIZATION OF CUP SHAPED PART WITH THICK BOSS PART

摘要

PURPOSE:To counterbalance hole opening force and hole closing force of a spline part, to decrease stress in quenching after carburization without increasing dead weight of the part and to improve vehicle performance, by coating carburization preventing agent on outer and inner circumferential surfaces of a spline part or on inside surface of a flange part, then quenching after carburization of the part. CONSTITUTION:At quenching after carburization a cup shaped part 1 having a thick boss part 2 in which the part 2 almost at the center and the thinner spline part 3 than this at outer circumference are connected with the flange part 4, a carburization preventing agent 6 is coated on outer and inner circumferential surfaces of the part 3 or on inside surface of the part 4. The part 1 is fed in carburization furnace under the state to carburization, successively thrown into quenching oil provided at furnace outlet for quenching. By such a method, hole closing force of the part 3 at carburization and hole opening force at quenching are relatively off-set and carburization-quenching stress is decreased.