激光熔覆钴基合金提高小口径深孔阀门密封面高温磨损性能的研究

Improving the High Temperature Wear Resistance of Seating Surface on Small-Bore Valve by Laser Cladding of Cobalt Base Alloy

利用自制的热冲击磨损试验设备，通过模拟小口径深孔阀门密封面的受力状态，测试了用于阀门密封面的三种焊层：激光熔覆ＷＦ１４１合金层，手工电弧堆焊Ｄ５７４Ｍｏ合金层和手工电弧堆焊丝１１１合金层的高温磨损性能。采用金相显微镜、扫描电镜和洛氏硬度计等对焊层的组织、表面磨损形貌和硬度进行了研究。结果表明，激光熔覆ＷＦ１４１合金层因其致密细小的枝晶组织和晶间鱼骨状共晶组织的存在，确保了焊层的高硬度值，在高温磨损的条件下显示出极高的塑性变形抗力，是三种焊层中耐高温磨损最优异的焊层。

A thermal impact-wear device made by ourselves was applied to test the high temperature wear resistance of seating surface on the small-bore valve through simulating the forced condition of the valve. These coated seating surfaces include the laser clad WF141 coating,the handwork arc hardfaced Wire 111 coating and the handwork arc hardfaced D547Mo coating. The microstructure,the wear profile and the hardness of coatings were investigated using an optical microscope,a scanning electron microscope and a Rockwell hardness tester. Result shows that the laser clad WF141 coating possesses the best high temperature wear resistance among three coatings because of its high hardness and its excellent resistance to plastic deformation which are contributed by the dense and fine dendrite,the fishbonelike eutectic in grain boundaries