Abstract:The surface of 45 steel was remelted by using laser surface remelting strengthening technology.With microhardness and wear rate as indicators,the indluence of laser power,scanning speed,beam diameter and pulse width on the comprehensive properties of 45 steel was investigated.It is found that laser power has the greatest influence on the comprehensive properties of 45 steel surface,followed by spot diameter,scanning velocity,laser pulse width.The optimum laser surface hardening parameters are 650 W of laser power,100 mm/min of scanning speed,4 mm of spot diameter and 2.4 ms of pulse width.The micro hardness and wear rate of the samples prepared by optimum laser surface hardening parameters were tested by hardness tester and friction and wear tester.The results show that the hardness distribution of laser hardening layer prepared with optimized parameters is more uniform and the hardness value is higher,the wear rate is obviously lower than that of the sample before parameter optimization.The wear mechanism of the samples before parameter optimization is fatigue wear,abrasive wear and adhesion wear.After optimization,there are only some small scratches on the wear surface of the samples,and the wear resistance is obviously improved.