喷焊镍基合金液力反馈抽油泵柱塞失效分析

用电子显微分析（SEM）和X射线能谱分析（XRD）研究喷焊镍基自熔合金柱塞失效的原因。结果表明，喷焊柱塞镍基合金涂层在井下硫-氧-碳混合气氛的工况环境中发生硫化和氧化腐蚀反应，生成以CrS，Cr₃S₄，Ni₃S₂，FeS和NiO等多元复合且疏松、可剥离的金属硫化物和氧化物垢盐类组织相，使柱塞直径尺寸胀大，配合超差，且涂层表面硬度明显下降。通过分析喷焊镍基合金涂层的腐蚀机理，提出加入可细化组织晶粒并且具有优异的抗硫化能力的合金元素Mo和Nb，明显提高其抗硫化能力和综合使用性能。

FAILURE ANALYSIS OF PLUNGERS SPRAYED BY Ni-BASE ALLOY ON HYDRAULIC FEEDBACK SUBSURFACE PUMP

The causes of failure of plungers sprayed by Ni-base alloy were investigated by means of scan- ning electron microscopy（SEM） and X-ray diffraction meter（XRD）.The results indicate that sulfuration and oxidation corrosion occurs in Ni-base alloy coatings of plungers operating in S-O-C mixture condition in oil wells,the complicated loosing and peeling sulfide and oxide salt-like microstructure phase,such as CrS,Cr₃S₄, Mi₃S₂,FeS,NiO and other phase are produced to enlarge the diameter of the plungers and make the plungers match difficultly,the hardness of the coating surface remarkably decreases.The corrosion mechanism of Ni-base coatings was studied to prove that the sulfuration resistance and comprehensive applications are dramatically improved by adding Mo and Nb which can refine the grain size and have excellent sulfuration resistance.