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目的 提高35CrMo钻杆接头和对磨套管的耐磨性能.方法 采用超声表面加工处理和硫氮共渗处理技术对钻杆接头常用的35CrMo钢进行处理,研究了超声表面预处理和润滑条件对其耐磨性能的影响.利用光学三维形貌仪、扫描电子显微镜(SEM)、能谱仪(EDS)和X射线衍射仪(XRD)分别研究了试样的表面形貌、粗糙度、成分和相结构,采用环块磨损试验机在油基钻井液润滑和无钻井液润滑的条件下,考察了经过不同载荷超声表面加工预处理的35CrMo钻杆接头及其对磨套管的磨损性能.结果 超声表面加工预处理可使35CrMo钢及其硫氮共渗处理后的表面粗糙度显著降低约80%以上.经超声表面加工预处理后,35CrMo钢硫氮共渗钻杆接头在油基钻井液润滑和干摩擦条件下的磨损率均进一步降低.在无钻井液润滑的条件下,500 N载荷超声表面加工预处理后,硫氮共渗35CrMo钢钻杆接头对磨油管磨损表面形貌的改善更显著,表面粘着和犁沟均减少.结论 35CrMo钢钻杆接头在硫氮共渗前采用超声表面加工进行预处理,可以获得更低的表面粗糙度和更高的表面硬度,在有无钻井液润滑条件下均可提高钻杆接头和套管的耐磨性能.

The work aims to improve wear resistance of 35CrMo steel used for drilling pipe joints and casing pipes. The 35CrMo steel was first pre-treated by ultrasonic surface processing and then by sulfonitriding treatment to study effects of sur-face pre-treatment and lubrication conditions on corrosion resistance of the steel. Surface morphology, roughness, composition and phase structure were characterized by optical profilometer, scanning electron microscopy (SEM), energy dispersive spec-trometer (EDS) and X-ray diffraction (XRD). The wear resistance of 35CrMo drilling pipe joints subject to ultrasonic surface pretreatment at different loads as well as casing pipes were evaluated by a ring-block wear tester with and without lubrication of oil-based drilling fluid respectively. The ultrasonic surface processing could remarkably reduce the surface roughness of both 35CrMo substrate and the samples with sulfonitriding treatment by over 80%. Sulfonitriding samples pre-treated by ultrasonic surface processing could obviously improve the wear resistance of 35CrMo steel with and without lubrication of oil-based drill-ing fluid. The ultrasonic surface processing under load of 500 N showed more obvious improvement in the wear resistance without lubrication of drilling fluid with the decrease of adhesion and furrows. Pretreating 35CrMo steel by ultrasonic surface processing and sulfonitriding treatment can obtain lower surface roughness and higher surface micro-hardness, and improve the wear resistance of both 35CrMo drilling pipe joints and casing pipe with and without lubrication of drilling fluid.