激光熔覆技术在高腐蚀环境下液压支架的试验研究

摘要

Based on the application of laser cladding technology on hydraulic support in high corrosive coal mine environment,iron-based stainless steel was selected as the research object.The chemical composition of stainless steel was tested by ICP-AES.The cladding layer was characterized by metallographic and SEM images.The influence of chemical elements on the hardness and corrosion resistance of cladding layer was studied by Rockwell hardness method and salt spray test method.The machining technological process after laser cladding was discussed.The results show that the cladding layer is obviously distinguished from the matrix.The metallurgical bonding occurs between the cladding layer and matrix.In addition,the microstructure of cladding layer is off-white marten site,showing dendritic crystal and elliptical and massive distribution.With the increasing of corrosion resisting alloy element Cr,Ni and Co in the stainless steel powder,the corrosion resistance ability of the cladding layer is improved.The hardness of the cladding layer can be changed by adjusting the content of B and C in the stainless steel powder,but the effect of B on the hardness of the cladding layer is more obvious than C.The best corrosion resistance ability can be acquired by controlling the cladding layer hardness in HRC 50 to 55.Through the study of cost and efficiency,vehicle-mill-polishing is the best solution for laser cladding.%基于激光熔覆技术在高腐蚀性煤矿环境下液压支架中的应用情况,选取铁基不锈钢为研究对象,采用ICP-AES法测试不锈钢中的化学成分,以金相组织、SEM图像表征熔覆层的微观结构,通过洛氏硬度法、盐雾试验法研究了化学成分元素对熔覆层硬度和耐腐蚀性能的影响,并探讨了激光熔覆后的加工工艺方案.结果表明,熔覆层与基体分界明显,呈现良好的冶金结合;金相组织结构为灰白色马氏体,呈现树枝状结晶和椭圆、块状分布;随着不锈钢粉末中Cr、Ni、Co等抗腐蚀合金元素的增加,熔覆层的耐腐蚀性能逐渐提高;调节不锈钢粉末中元素B、C的含量可以改变熔覆层的硬度,但B对熔覆层硬度的影响比C更明显;为保持良好的耐腐蚀性能,熔覆层硬度控制在HRC 50～ 55为最佳.通过对成本、效率分析研究,认为车-磨-抛光是激光熔覆最优的加工方案.