三元复合驱油井抽油杆激光熔覆涂层腐蚀性能研究

发布时间：2018-06-02 00:52

本文选题：三元复合驱 + 抽油杆　；参考：《东北石油大学》2015年硕士论文

【摘要】：本文结合三元复合驱油井抽油杆服役工况,采用激光熔覆技术制备不同铬含量的铁基激光熔覆涂层,研究涂层的组织、物相及硬度特征,测试其在三元复合驱工况中的腐蚀行为和腐蚀磨损特性,分析不同参数对其腐蚀和腐蚀磨损行为的影响规律和机理,为三元复合驱腐蚀磨损工况下,抽油杆激光熔覆涂层的开发和应用提供理论基础。激光熔敷涂层组织主要由熔覆区、合金化区和热影响区组成,枝晶和胞晶为主要金相特征,涂层与基体为冶金结合,涂层熔覆质量良好。涂层硬度远高于基体20CrMo,硬度随Cr含量增加而增加,含Cr40%的Fe-40Cr涂层存在较多Cr7C3、Cr23C6等碳化相,具有最高的硬度,接近HV 500。制备激光熔覆涂层在三元复合驱介质中点蚀电位高于基体20CrMo钢,具有优异的点蚀阻力。在不同三元复合驱溶液中钝化区间都较宽,钝化稳定性高。高Cr含量的Fe-40Cr涂层钝化稳定性最优。三元复合驱介质中的碱、聚丙烯酰胺浓度和涂层耐蚀性存在临界值,在碱和聚丙烯酰胺浓度分别为0.8%和800mg/L时,涂层的耐蚀性最强。表面活性剂浓度增加,对腐蚀的抑制作用增强,耐蚀性提高。温度的增加,由于反应活性的增加,降低了涂层的耐蚀性。激光熔覆涂层腐蚀磨损累积失重随时间的增加而呈上升趋势,涂层逐渐处于稳定磨损阶段。Cr含量增加,涂层抗腐蚀磨损性能提高,高Cr含量的Fe-40Cr涂层具有最低的腐蚀磨损失重量。三元复合驱介质浓度腐蚀性的好坏直接影响涂层腐蚀磨损性能的优劣。基体20CrMo钢硬度低,表面出现方向一致的颗粒划伤,形成典型的韧性冲刷磨损坑,激光熔覆涂层腐蚀磨损损伤源自于涂层熔覆搭接缺陷部位,高的硬度和高的耐蚀性使得Fe-40Cr涂层呈现出更优异的腐蚀磨损阻力。
[Abstract]:Combined with the service condition of sucker rod in ASP flooding well, the laser cladding technology was used to prepare iron-based laser cladding coating with different chromium content. The microstructure, phase and hardness of the coating were studied. The corrosion behavior and corrosion wear characteristics of ASP flooding were tested, and the influence of different parameters on corrosion and corrosion wear behavior was analyzed. The development and application of laser cladding coating on sucker rod provide theoretical basis. The microstructure of laser cladding coating is mainly composed of cladding zone, alloying zone and heat affected zone, dendrite and cell crystal are the main metallographic characteristics, the coating and substrate are metallurgical, and the cladding quality of the coating is good. The hardness of the coating is much higher than that of the substrate 20CrMo.The hardness of the coating increases with the increase of Cr content. There are many carbonized phases such as Cr7C3Cr23C6 and the hardness of the Fe-40Cr coating containing Cr40% is close to that of HV 500. The pitting potential of laser cladding coating is higher than that of 20CrMo steel in ternary flooding medium, and it has excellent pitting resistance. In different ASP flooding solutions, the passivation range is wide and the passivation stability is high. The passivation stability of Fe-40Cr coating with high Cr content is optimal. There are critical values of alkali, polyacrylamide concentration and corrosion resistance of the coating in ASP flooding medium. When the concentration of alkali and polyacrylamide is 0.8% and 800mg/L, respectively, the corrosion resistance of the coating is the strongest. With the increase of surfactant concentration, corrosion inhibition and corrosion resistance are enhanced. With the increase of temperature, the corrosion resistance of the coating is decreased because of the increase of reaction activity. The cumulative weight loss of laser cladding coating increased with the increase of time. The corrosion wear resistance of laser cladding coating increased with the increase of the content of .Cr in the stable wear stage, and the corrosion wear resistance of laser cladding coating increased with the increase of time. The Fe-40Cr coating with high Cr content has the lowest corrosion wear loss weight. The corrosion of ASP flooding medium directly affects the corrosion and wear performance of the coating. The hardness of the substrate 20CrMo steel is low and the surface of the steel is scratched in the same direction, forming a typical ductile erosion wear pit. The corrosion wear damage of the laser cladding coating originates from the position of the cladding defect of the coating. High hardness and high corrosion resistance result in better corrosion resistance of Fe-40Cr coating.
【学位授予单位】：东北石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE983

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