钻井泵泵阀阀面失效分析及堆焊研究

发布时间：2018-01-15 13:25

本文关键词：钻井泵泵阀阀面失效分析及堆焊研究　出处：《西南石油大学》2017年硕士论文　论文类型：学位论文

【摘要】：随着石油钻采的快速发展,国内油气田对钻井泵的需求必然是越来越大,钻井泵的工作环境只会越来越恶劣。而钻井泵开启关闭时接触含泥砂而且带有腐蚀性的泥浆并且承受着高压泵所造成的液力负荷,对泵阀表面进行冲蚀,在周期应力作用下产生疲劳,阀体和阀座是钻井泥浆泵最易失效零件之一,在现场经常更换,浪费大量时间。针对上述问题,本文对钻井泵泵阀阀面进行宏观和微观失效分析找出阀面失效的主要原因;采用钨极氩弧焊技术对泵阀阀面进行Stellite6钴基合金堆焊,实施有无堆焊层的硬度测试、冲击韧性对比试验、磨损对比试验,表明阀面堆焊钴基合金可以提高泵阀的性能;利用Mathcad软件对阀体运动进行近似计算,将获得的结果作为初始条件,编写UDF语言对泵阀阀面开展流场仿真分析,对阀面剪切力和冲刷特性进行分析研究;最后对阀面不同材料的疲劳寿命进行初步的分析研究。在研究过程中,得到如下主要成果:(1)借助于扫描镜和金相显微镜对报废的泥浆泵泵阀阀体和阀座阀面进行宏观和微观失效分析,并对阀座材料及热处理组织进行分析,确立了阀面主要失效原因为磨料磨损、冲蚀磨损、疲劳磨损等。(2)通过TIG堆焊技术在20CrMnTi钢表面堆焊钴基合金,元素浓度梯度大,扩散作用强,在堆焊过程中,在熔合线处出现了堆焊层与母材间元素的互相扩散,冶金结合良好。堆焊后的阀面力学性能通过试验验证表明得到一定的提高,有堆焊层的阀面的平均洛氏硬度HRC为45,维氏硬度HV为412,冲击韧性较未堆焊时提高20%,质量磨损量仅是未堆焊时的32%左右。(3)在泵阀吸入冲程的流场中,泵阀吸入阀阀体和阀座所受剪切力作用呈现先增加后减小的趋势。阀体壁面剪切力作用最大的地方在阀体锥面,阀座壁面剪切力作用最大的地方在阀座锥面与垂直面的交界处。由于阀体和阀座本身的结构特征,阀体和阀座锥面与垂直面之间有过渡,阀隙处的阀面受力相对于其他位置更大,这是阀体和阀座下端部分容易出现块状脱落的主要原因。(4)由于阀面钻井液冲刷作用严重,分析阀面的冲刷磨损特性得到阀面有无堆焊层的冲刷破坏分布趋势基本一致,且泵阀表面磨损的分布趋势与剪切力的分布趋势基本一致。针对阀面有无堆焊层的情况发现,泵阀工作表面堆焊钴基合金后能有效的降低阀面受到的冲刷和磨损作用。本文在研究分析阀面失效的工作中,通过试验和仿真在一定程度上找到了阀面失效的主要原因,并说明了对泵阀阀面进行钨极氩弧焊堆焊Stellite6钴基合金以提高阀面性能的可行性。对于后续对钻井泵泵阀阀面的强化具有一定的参考价值。
[Abstract]:With the rapid development of petroleum drilling, domestic demand for oil and gas field of drilling pump is more and more big, the drilling pump working environment will become more and more severe. Hydraulic load of drilling pump to open and close contact with sand and mud and mud with corrosive and under high pressure pump caused by the erosive of valve the surface in cycle fatigue under the force of the valve body and the valve seat is the most prone to failure of drilling mud pump parts, often replaced in the field, wasting a lot of time. To solve the above problems, the drilling pump valve of macro and micro failure analysis and find out the main reason why the valve face failure; Stellite6 cobalt base alloy surfacing on valve surface by argon tungsten arc welding technology, the implementation of non surfacing layer hardness test, impact toughness test, wear test, shows that the valve surfacing cobalt based alloy can improve the valve The performance of body movement; approximate calculation by using Mathcad software, the results will be obtained as the initial conditions, simulation and analysis of flow field of the valve valve prepared for the UDF language, to analyze the valve shear stress and erosion characteristics; at the end of the valve surface of different materials, the fatigue life is studied in the course of the study. And the main results obtained are as follows: (1) with the aid of scanning mirror and optical microscope to scrap the mud pump valve body and valve seat surface in macroscopic and microcosmic failure analysis, and the seat material and heat treatment microstructure analysis, establishes the main failure reason for valve surface erosion wear, abrasive wear, fatigue wear and so on. (2) by TIG surfacing deposited on the surface of 20CrMnTi steel cobalt base alloy element concentration gradient, the diffusion effect is strong, in the welding process, the fusion line appeared at each element expansion surfacing layer and base material between Powder, good metallurgical bonding. The mechanical properties of the surfacing valve face after the experiments proved that the improved, a valve surfacing layer the average Rockwell hardness of HRC 45, Vivtorinox HV hardness was 412, increased by 20% compared to non impact toughness of welding quality, the wear volume is not only about 32% (when surfacing. 3) in the flow valve in the suction stroke, the intake valve valve valve and valve seat shear force increases first and then decreases. The wall shear stress in the body of the largest local cone, where the seat wall shear stress plays the most important role in the seat cone with a vertical surface junction. The structural characteristics of the valve and the seat itself, there is a transition between the valve body and the valve seat surface and the vertical force position relative to other larger valve gap valve surface, this is the lower part of the valve body and the valve seat is easy to appear the main reason of massive fall off. (4) the valve surface Drilling fluid erosion is serious, the erosion wear characteristics analysis of valve valve surface without surfacing layer erosion distribution trend is basically the same, the distribution trend of distribution trend and the shear force and the valve surface wear is basically the same. That on valve surface without surfacing layer, valve surfacing cobalt based alloy can effectively the lower valve surface is erosion and abrasion. Based on the analysis of valve failure surface work, through experiment and simulation to find the main reasons to a certain extent, the valve face failure, and that of the valve valve surface by TIG welding of Stellite6 alloy in order to improve the feasibility of the valve surface performance. For the follow-up of drilling pump valve surface strengthening has a certain reference value.

【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TE92

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