In order to explore the feasibility of CM550 composite wear-resistant plate used in the middle trough of scraper conveyor in coal mine,the microstructure and wear performance of high chromium hardfacing wear-resistant layer were studied,and the wear damage mechanism was analyzed,combined with the wear movement characteristics of middle groove for the scraper conveyor.The microstructure analysis of metallography,XRD and TEM shows that the metallurgical fusion is formed between the hardfacing layer and Q235 base steel.The phase composition of hardfacing layer is mainly α-Fe and Cr7C3 carbide,in which the carbide exists in the forms of primary rod carbides,eutectic flake carbides and secondary granular carbides.The formation of hard Cr7C3 carbides increases the hardness of hardfacing layer,which effectively improves its sliding wear resistance.The experimental results of sliding wear reveal that the relative wear resistance of CM550 hardfacing plate is more than two times that of NM450 wear-resistant steel,and the wear mass loss of friction pair material is also at the same level at the similar friction coefficients,which fully meets the design and application requirements of middle trough of scraper conveyor.Under the condition of sliding abrasive wear of quartz sand,the wear damage mainly comes from the ploughing wear of hard quartz sand particles and the deformation peeling wear of soft ferrite area.After ferrite wear,the hard carbides exposed on the wear surface not only bear the main wear load,but also prevent the direct contact between quartz sand particles and soft ferrite,and avoid the further wear of ferrite.Therefore,the CM550 high chromium hardfacing wear-resistant plate is recommended as a wear-resistant material for the manufactures of middle trough of scraper conveyor and various wear-resistant lining plates in coal mine.