石油钻具零件塑性流动与精密成形技术研究

发布时间：2018-07-09 15:24

  本文选题：石油钻杆接头 + 精密塑性成形　； 参考：《上海工程技术大学》2015年硕士论文

【摘要】：随着全球能源需求增加,能源紧缺,以石油为代表的一次能源的开采难度增加,对钻具的技术要求也随之增高。石油钻具属于易耗型工业产品,工作环境恶劣,受力条件复杂,受到扭曲、拉伸、冲击等复合力的作用,对材料及其加工技术的要求较高。本文以石油钻具中的典型零件钻杆接头为研究对象,接头的材料为37CrMnMo中碳低合金钢。接头是钻杆的重要连接部件,在钻井过程中要经常拆卸,受到大钳绞合力的作用,受力条件复杂。传统的成形工艺为半自由锻成形,尺寸精度低、材料消耗大、能源消耗高,内部金属流线容易受到破坏。以温挤压为代表的精密塑性成形是一种少无切削的塑性成形方法,零件精度高,可以部分去除后道切削加工工序,且有利于改善金属内部流线分布状态,锻件质量和力学性能显著提高。本文采用精密塑性成形技术,可提高锻件尺寸精度和材料利用率,改善锻件质量,降低能源消耗。通过热物理实验,分析石油钻杆接头用钢材料在高温时的流变性能,得出变形温度(T)及应变速率(ε)对金属流变应力(σ)的影响规律,在此基础上,根据Arrhenius方程及对热压缩数据的分析,得应力指数n=6.56091642以及热激活能Q=284.039529KJ/mol,建立了37CrMnMo钢高温流动时的应力本构方程。对石油钻杆接头成形工艺进行分析,确定分模面、加工余量、公差、拔模斜度及关键成形部位的圆角半径,建立合适的物理模型。从预制坯形状及连皮位置关键参数入手,以解决锻件充不足,金属流动阻力大,锻件内部温度分布不均的问题。从变形温度(T)、挤压速度(V)、台阶处圆角半径(r)入手,以获得锻件成形规律,提高锻件质量,降低成形载荷。基于刚粘塑性有限元法,对石油钻杆接头精密塑性成形过程进行模拟。分析不同预制坯形状及连皮位置对锻件的温度场、应力及应变场、载荷情况、金属流动情况、金属内部流线分布的影响,综合得出最优预制坯形状及连皮位置。研究石油钻杆接头精密塑性成形过程中工艺参数因素对锻件质量的影响。采用正交试验,分析了零件成形温度(T)、压力机速度(V)、台阶处圆角半径(r)等工艺参数对最大等效应力、载荷及温度场的影响。通过极差分析及综合平衡分析,获得了石油钻杆接头37CrMnMo钢温挤压精密成形中各参数的影响显著性,得到了最优工艺参数组合：温度为780℃,挤压速度为30mm/s,台阶处圆角半径为4mm。将最优条件下的模拟结果进行分析并应用于实际生产中,对分析结果进行实验验证,结果表明,该条件下生产的制件符合实际要求。本文对石油钻杆接头实际生产中的工艺优化及锻件质量问题的研究,对于提高锻件组织性能,进一步改变成形工艺提供理论依据及指导。
[Abstract]:With the increase of global energy demand and energy shortage, it is more difficult to exploit primary energy represented by oil, and the technical requirements of drilling tools are also increased. Oil drilling tools are consumable industrial products. The working environment is bad, the stress conditions are complex, and they are affected by the complex forces such as distortion, tension, impact, etc., so the requirements for materials and their processing technology are higher. In this paper, the typical drill pipe joint of petroleum drilling tools is studied. The material of the joint is 37CrMnMo medium carbon low alloy steel. The joint is an important connecting part of drill pipe. It is often disassembled during drilling and is subjected to the action of the force of the forceps, so the stress condition is complicated. The traditional forming process is semi-free forging, which has low dimensional precision, large material consumption, high energy consumption, and internal metal streamline is easy to be destroyed. Precision plastic forming, represented by warm extrusion, is a kind of plastic forming method with little cutting and no cutting. The precision of parts is high, the back cutting process can be partially removed, and the streamline distribution in metal can be improved. The quality and mechanical properties of forgings are greatly improved. In this paper, the precision plastic forming technology is used to improve the dimension precision and material utilization ratio of forgings, improve the quality of forgings and reduce the energy consumption. In this paper, the rheological properties of steel materials used in oil drill pipe joints at high temperature are analyzed through thermophysical experiments. The effects of deformation temperature (T) and strain rate (蔚) on metal rheological stress (蟽) are obtained. Based on the Arrhenius equation and the analysis of the thermal compression data, the stress exponent nv 6.56091642 and the thermal activation energy QF 284.039529KJ / mol are obtained. The stress constitutive equation of 37CrMnMo steel under high temperature flow is established. The forming process of oil drill pipe joint is analyzed, and a suitable physical model is established by determining the parting surface, machining allowance, tolerance, drawing die inclination and the radius of the corner of the key forming position. Based on the key parameters of the preform and the position of the connecting skin, the problems of insufficient filling of the forgings, large metal flow resistance and uneven internal temperature distribution of the forgings are solved. Starting from the deformation temperature (T), extrusion speed (V) and (r) of the corner radius at the step, the forming rule of the forgings is obtained, the quality of the forgings is improved and the forming load is reduced. Based on rigid viscoplastic finite element method, the precision plastic forming process of oil drill pipe joint is simulated. The effects of different preform and position of preform on the temperature field, stress and strain field, load, metal flow and the distribution of flow line inside metal are analyzed, and the optimum preform and concatenation position of preform are obtained. The influence of process parameters on forging quality in the process of precision plastic forming of drill pipe joint is studied. The effects of forming temperature (T), press speed (V) and corner radius (r) on the maximum equivalent stress, load and temperature field are analyzed by orthogonal test. By means of range analysis and comprehensive balance analysis, the influence of various parameters on the precision forming of 37CrMnMo steel is obtained. The optimum technological parameters are as follows: the temperature is 780 鈩，

本文编号：2109803