Study on the effects of laser quenching power and scanning speed on the property of cast iron

Abstract

The laser surface quenching power, scanning speed, and spot area have significant effect on the properties of the laser quenched materials. The effects of laser quenching power and scanning speed on the tribological, vibration, and noise performance of gray cast iron (HT250) are studied in this paper. Keeping the laser quenching spot constant, 12 cast iron discs are laser quenched by changing the laser quenching power and scanning speed. Various mechanical, tribological, and dynamical testing equipment are used to characterize the properties of the laser quenched cast iron discs, in terms of the surface hardness, residual stress, friction coefficient, and frictional vibrations and noise of the cast iron discs. The experimental results show that after laser surface quenching, the surface hardness of the cast iron disc has been increased more than 4 times, the residual stress on the disc surface is changed from tensile stress to compressive stress, the friction coefficients of the laser quenched cast iron discs have been significantly increased, and the vibration and noise generated from the laser quenched cast iron discs have been significantly changed. This research has significance to the improvement of the surface performance of automotive brake discs and the control of braking frictional vibrations and noise.