Effect of laser power parameters on microstructure and wear resistance of GCr15 steel

To investigate the effect of laser power parameters on the microstructure,hardness and wear resistance,the laser hardening treatment was performed for GCr15 steel by wide band scanning technology.The laser-quenched specimens were characterized by optical microscope,scanning electron microscopy and X-ray diffractometer.The wear tests were carried out on a MM200 wear tester.The results show that the microstructural variation caused by changing the laser power parameters leads to the larger difference in both surface hardness and wear rate.With increasing the laser power,the amount of undissolved carbides on the laser hardened layer surface decreases and the average carbon content of the surface martensite increases,which will lead to an increase in surface hardness.In addition,the friction induced martensite transformation takes place on the laser hardened layer surface during dry friction and wear test.At the lager laser power,the wear resistance of the laser hardened layer is better in the conditions of dry friction and oil lubrication.