金属Mo对液压油缸铁基熔覆层微观组织和服役性能的影响

Effect of Mo on Microstructure and Service Performance of Fe-based Cladding Coating on Hydraulic Cylinder

选择常规低碳高铬铁基熔覆粉末为原始材料,利用激光熔覆技术制备了不同Mo加入量的铁基熔覆层,分析了金属Mo对熔覆层组织和服役行为的影响。结果表明:随着Mo元素的加入,马氏体不锈钢熔覆层逐渐出现残余奥氏体和M_(23)(C,B)_(6)相。同时,熔覆层发生胞状晶-柱状晶-等轴晶的组织转变。此外,随着Mo含量的增加,马氏体不锈钢熔覆层的自腐蚀电位、自腐蚀电流和阻抗均呈现先升高后降低的变化,熔覆层的耐蚀性呈现先增加后降低的改变;同时,熔覆层硬度逐渐降低,且腐蚀介质下熔覆层的润滑与耐磨性均出现了不同程度的恶化。提高马氏体不锈钢熔覆层的Mo含量虽造成熔覆层耐磨性稍有降低,但明显改善了材料的耐蚀性,可以满足苛刻的煤矿液压支架防护要求。

The conventional iron-based cladding powder and metal Mo powder was selected as the raw material,the Fe-based cladding coating with different Mo content were prepared by laser cladding technology and the effect of Mo on the microstructure and service behavior of the cladding coating was analyzed.The results show that with the addition of Mo element,retained austenite and M_(23)(C,B)_(6) phase gradully appeared in the cladding layer of martensitic stainless steel.Meanwhile,the microstructure of the cladding coating changes from cellular crystal,columnar crystal to equiaxed crystal.In addition,with the increase of Mo content,the corrosion potential,corrosion current and impedance of the martensitic cladding coating increase first and then decrease,indicating that the corrosion resistance of the cladding layer increases first and then decreases.Meanwhile,the hardness and the wear resistance of the cladding coating of the cladding coating decreases gradually.Therefore,the corrosion resistance of the Fe-based cladding coating is obviously improved,although the wear resistance is slightly reduced with the increasing the Mo content,which can meet the protection requirements of hydraulic support under the harsh coal mine.