Research On Microstructure And Properties Of X-M6V Wear-resistant Coating By Extreme-high Speed Laser Cladding On The Surface Of 45# Steel

In the cold steel rolling process,the roll is a key component of the rolled s teel plate.During working,it is extremely susceptible to the impact and wear of the steel plate,which makes the roll surface peel and wear,resulting in failure a nd scrap.Therefore,it is necessary to prepare a High wear-resistant Hard coating o n the surface of the roll to increase the service life of the roll,thereby improvin g productivity and saving costs.As a new surface treatment technology,ertremehigh speed laser cladding technology can prepare High wear-resistant Hard coating,which Has great advantages in the metallurgical industry.The rate of extreme-high-speed laser cladding reaches 10-200m/min.Under e xtremely High Heating and cooling rates,the solidification behavior of coating m aterials Has a special law.In this paper,based on the preparation of composite c oatings to improve the resistance layer,through a reasonable choice of powder s ystem,under the process conditions of High lap rate and High solidification rate,after optimizing the process,a thin-walled wear-resistant coating with High Har dness and uniform microstructure are obtained.The law of the influence of ener gy on the coating microstructure,establishing the correlation between the coating microstructure and performance,revealing the coating enhancement mechanism,a nd comparing with the performance of the coating prepared by conventional laser cladding technology.The study found that under ultra-high speed laser cladding conditions,by ad opting powder drying for 5 Hours,substrate preheating at 200°C,and slow cooli ng after cladding optimization measures,crack-free X-M6V and Ni625-40%WC c oatings can be achieved of preparation.Comparative analysis of the macro and micro quality,Hardness,uniformity of Hardness distribution and wear resistance of the two coatings.As a result,it was found that the X-M6V coating Had better performance,and it was determined that the iron-based alloy X-M6V powder tha t could achieve in-situ reinforcement was used as the material to prepare the we ar-resistant coating.Further analysis of the ultra-high-speed laser cladding X-M6V coating thickn ess,Heat affected zone,dilution rate and surface roughness and other macro char acteristics.It was found that the coating microstructure was mainly composed of primary crystal Fe-based cell solid solution rich in alloying elements such as Cr and Mn,dispersed fine carbides M₂₃C₆?M=Cr,Fe?and M₇C₃,and VC precipita ted phases.The overlapping area on the coating surface is a chrysanthemum-shap ed VC,and the non-lapping area is a spherical VC.The linear energy Has little effect on the coating microstructure and phase composition.When the convention al laser cladding method is used,the precipitation of VCHard phase cannot be a chieved in the X-M6V coating due to the insufficient cooling rate of the molten pool.The extreme-high-speed laser cladding X-M6V coating Hardness is much High er than the Hardness value of the 45# steel substrate,and the coating surface Hard ness Has excellent uniformity.The Hardness and wear resistance of the extreme-hig h speed laser cladding X-M6V coating are little affected by the line energy,and are superior to the conventional laser cladding X-M6V coating.The enhancement mechanisms are dispersion strengthening,particle strengthening,fine crystal streng thening and Solid solution strengthening.