Experiment Research On Wear Resistance Of Ht250 Guideway For Laser Surface Hardening

After the emergence of laser heat treatment technology,scholars at home and abroad have done a lot of research on improving the surface quality of metal parts by using laser technology,then making the laser surface treatment technology have very mature application.Gray cast iron is widely used in machine tool guideways because of its vibration-damping performance and good casting processing performance.As a reference part of machine tool motion,the wear resistance of the guideways has a great influence on the machining accuracy and working life of the machine tools.In order to improve the wear resistance and scratch resistance of the machine grey iron guideways,ensure the machining precision of the machine tools and extend the service life of the machine tools,the traditional heat treatment technology can no longer meet the further development of the machine tools.Therefore,to study new technology to improve machine guideways wear resistance and service life is particularly important.In view of the defects such as large deformation and uneven quenching of the guideways in the conventional high-frequency induction quenching conditions,this paper applied the laser surface hardening technology to the machine guideways,and the wear resistance test research was carried out,tcompared the conventional high-frequency induction quenching machine guideway samples to analyze the laser surface hardening samples,then some valuable conclusions were obtained finally.In this paper,the laser surface hardening process on gray iron HT250 guideway of a machine tools were tested by transverse flow CO₂ laser.By analyzing the surface morphology,microstructure,microhardness and hardening layer uniformity of the gray cast iron HT250guideway under different laser surface hardening parameters,then the optimum process parameters were preliminarily optimized;by comparing with the high-frequency induction hardening guideway samples.It is found that the martensitic structure and graphite particles in the phase change hardening zone of the HT250 guideway specimen of the surface quenched gray cast iron were relatively small,and the distribution was relatively uniform;the depth of the hardened layer was shallow,but the surface hardness was slightly higher.The friction and wear test was carried to analyze the wear-resistance of the HT250specimens hardened by the laser surface hardening.Under the same friction and wear test conditions,it was found that the wear-resistance of the laser surface hardened specimen was greatly improved,about 2 times of the high frequency induction hardening sample.Through the analysis of friction coefficient and surface wear morphology,the wear mechanism of CO₂laser surface hardening specimen was mainly abrasive wear in in the process of friction and wear test.It is found that the friction and wear mechanism of the laser surface quenching guide specimen is mainly abrasive wear.