单体液压支柱激光熔覆层的组织与摩擦学特性

Microstructure and Tribological Properties of Laser Cladding Layer on Hydraulic Support

为延长单体液压支柱的使用寿命,在矿用单体液压支柱用钢27Si Mn表面激光熔覆Fe基合金粉末,制备多道熔覆层;分别对其显微组织、显微硬度和耐磨性进行分析研究。结果表明熔覆层无裂纹,与基体呈冶金结合,组织均匀,为细密枝晶组织;熔覆层的平均硬度为636.27 HV0.3,是基体的1.93倍;前后两道搭接区的硬度高于未搭接区的硬度;熔覆层在50~200 N的载荷条件下耐磨性良好,第二道与第三道熔覆层搭接区的耐磨性最好;熔覆层在50~200 N载荷时,磨损过程非常平稳,随载荷增加,摩擦系数降低,载荷大于250 N,磨损过程变得不平稳。

To prolong the service life of hydraulic support, Fe-base alloy powder was laser claded on the surface of hydraulic support which was made of 27 Si Mn steel used in coal mines, and multi-pass cladding layer was prepared. The microstructure, microhardness and corrosion resistance of cladding layer were studied. The results show that the crack-free layer has strong metallurgical bond with matrix, and the microstructure with well-develop dendrite is uniform. The hardness of cladding layer is 1.93 times of the matrix which reaches an average of 636.27 HV0.3. The hardness of two-pass overlapping area is higher than that of the no lap zone. Cladding layer at 50-200 N loading conditions shows good wear resistance and the best wearability lies in the the overlapping area of cladding layer of the second-pass and the third-pass, which is about 2times to the matrix. Cladding layer at 50-200 N loading conditions shows that the wear process is very smooth and with the increase of load, the friction coefficient decreases gradually. When the load is more than 250 N, the wear process is not stable.