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Experimental study of the laser quenching of 40CrNiMoA steel

1999; Elsevier BV; Volume: 88; Issue: 1-3 Linguagem: Inglês

10.1016/s0924-0136(98)00381-1

1873-4774

Qingbin Liu, Liu Hong,

Metal and Thin Film Mechanics

The service life of the piston head and the stability of a large diesel engine are greatly affected by the wear resistance of the groove of the piston head. Conventional high-frequency quench-and-temper treatment results in several deleterious effects that may impair the anti-friction and wear properties of the groove of the piston head. Laser surface quenching is a new candidate technique. In this study, based on orthogonal experimental design, the effect of the surface condition, the laser power, the traverse speed, the incident angle and the gas flow rate on the quenched zone of 40CrNiMoA steel was investigated systematically. The profile, hardness and microstructure of the quenched zone vary with the surface condition, the laser power, the incident angle and the traverse speed. However, they are not significantly affected by the gas flow rate. The optimum processing parameters are obtained for the laser quenching of the groove of the piston head. Using the optimum processing parameters, quenched zones with not only sufficient case depth and greater hardness but also of a suitable profile and a finer microstructure, are obtainable. The hardness of the laser quenched zone is substantially higher than that resulting from conventional high-frequency quench-and-temper treatment.