针对石油钻探井口机械在长期高频、高负载工况条件下重要受力部件牙板极易磨损的问题, 采用激光在牙板表面制备阵列凹坑, 以提高其耐磨损性能。利用波长1 064 nm、功率500 W的多功能脉冲激光加工机对牙板 42CrMo合金钢表面进行激光织构化处理, 制备出直径为800 μm, 间距分别为1.8、1.5、1.2 mm的阵列凹坑; 分别用金相显微镜和超景深三维显微镜观察试件表面二维和三维形貌; 利用MMH-5环块三体摩损试验机进行了摩擦实验, 通过摩擦前后的试件质量差和磨损区域表面厚度的变化, 比较了激光织构化处理前后表面的耐磨损效果, 分析了耐磨损的机理, 并研究了阵列凹坑不同间距对滑动摩擦耐磨性能的影响。结果表明, 在相同摩擦工况条件下, 阵列凹坑激光织构化表面比未织构表面耐磨损性能要好, 并且凹坑占有率越大, 磨损量越小, 间距为1.2 mm的织构化表面磨损量减少86.03% 。磨损机制主要为磨粒磨损。阵列凹坑结构化表面耐磨损性能提高的主要原因有: 一是激光相变硬化作用, 提高了试件表面硬度; 二是阵列凹坑织构表面在摩擦过程中对犁沟起到破坏作用, 从而减缓了磨粒磨损。

Tooth plates which are the key mechanical parts on oil drilling wellhead machinery are easily worn under the long-term, high frequency and high load conditions. The array pits are prepared on the surface of the tooth plates by laser to improve its anti-wear property. The rule of the array pits with the diameter of 800 μm and the spacing of 1.8 mm, 1.5 mm, 1.2 mm on 42CrMo alloy steel were prepared at impulse laser with a wavelength of 1 064 nm and power of 500 W. The two-dimensional and three-dimensional morphology of the specimen were observed with a metallurgical microscope and depth of field 3D microscope. The friction tests were performed by using MMH-5 ring block three body wear tester. The influence of the array pits with different spacing to anti-wear property, and the mechanism were analyzed through comparing the difference of the quality of the specimen and the thickness and weight of specimen before and after the laser texturing. The results show that the wear of textured specimens has been significantly reduced with reference to that un-textured specimens in the same condition, with the content of the pit is larger, the wear mass is lighter, and weight of the array pit surface with the spacing of 1.2 mm decreased 86.03%. Abrasive wear is main wear mechanism. The main reasons which array pits surface improve the property of anti-wear include: one is that laser phase-hardening effect, which improves the surface hardness of the specimen; the other is that the textured surface of the array pits has a damaging effect on the furrow during the rubbing process, thus slowing the abrasive wear.