重熔对激光熔覆Fe60涂层的组织与性能影响

Effect of remelting on microstructure and properties of laser cladding Fe60 coating

为提高45#钢表面的显微硬度及耐磨性能,以Fe60自熔性合金粉末作为熔覆层原料,通过激光熔覆和激光重熔工艺制备熔覆涂层。利用扫描电子显微镜(SEM)观察涂层的显微组织,利用维氏硬度计、磨损实验机、三维形貌仪等仪器进行显微硬度、耐磨性能及磨损机制的测试。结果表明:激光熔覆制备的涂层枝晶组织尺寸较大,激光重熔后的涂层枝晶晶粒细化且更加致密。相较于基体,激光熔覆制备的涂层平均硬度为670 HV,是基体的3.38倍,激光重熔后的涂层平均硬度为682 HV,相较于基体硬度提升3.43倍。经过激光重熔及激光熔覆涂层的摩擦系数、磨损量相较于基体得到显著降低,其磨损量分别降低了8倍、2.67倍,耐磨性能得到显著提升,涂层的摩擦磨损形式为磨粒磨损及黏着磨损。

In order to improve the microhardness and wear resistance of 45#steel surface,Fe60 self-fusible alloy powder was used as cladding material to prepare cladding coating by laser cladding and laser remelting process.The microstructure of the coating was observed by scanning electron microscope(SEM),and the microhardness,wear resistance and wear mechanism of the coating were measured by Vickers hardness tester,wear test machine and three-dimensional morphometer.The results show that the microstructure of the coating dendrites prepared by laser cladding is larger,and the dendrite grains are finer and denser after laser remelting.Planar crystals are formed in the bonding regions of laser cladding coating,laser remelting coating and matrix,which results in metallurgical bonding.Compared with the matrix,the average hardness of the coating prepared by laser cladding is 682 HV,which is 3.43 times that of the matrix.The average hardness of the coating after laser remelting is 670 HV,which is 3.38 times higher than that of the matrix.After laser remelting and laser cladding,the friction coefficient and wear amount of the coating are significantly reduced compared with the matrix,and the wear amount is reduced by 8 times and 2.67 times,respectively,and the wear resistance is significantly improved.The friction and wear forms of the coating are abrasive wear and adhesive wear.