组装工艺对铝合金钻杆性能的影响及自动化组装装置研制

Influence of Assembly Process on the Performance of Aluminum Alloy Drilling Rod and Development of Automatic Assembly Device

为了满足日益增长的深部钻探对钻杆的性能要求,需要研制可以适应极端工况的轻质高强度钻杆。铝合金钻杆具有密度小、比强度高、耐腐蚀性强等优点,但耐磨性和螺纹强度不足。在实际使用过程中,铝合金钻杆需配合钢接头一起使用,主要由钢接头承受拧卸力。目前国内外的铝合金钻杆组装技术主要有预扭矩法、热组装技术和冷组装技术。热组装技术在实际应用中表现出更适合深孔钻井铝合金钻杆的特性,但组装过程中的高温会降低铝合金杆体螺纹部位的强度。本文对铝合金钻杆杆体与钢接头热组装过程中的实际温度进行了测量试验,试验结果表明外冷却可以避免铝合金钻杆杆体螺纹部位较长时间处于较高温度,而内冷却可以使螺纹部位的最高温度降低25℃左右。对螺纹连接部位做轴向拉伸有限元分析,通过公式拟合得出螺纹根部最大应力与轴向拉力之间的关系,公式计算表明热组装过程中存在的高温会使铝合金钻杆最大轴向拉力下降约65 kN。由试验与模拟结果可见内外冷却机构对于热组装装置的重要性,作者结合前期工作,介绍一套全尺寸铝合金钻杆杆体和钢接头自动化过盈热组装装置的研制。

In order to meet the ever-increasing performance requirements for drilling rod in deep drilling,it is necessary to develop lightweight and high-strength drilling rod that can adapt to extreme working conditions.Aluminum alloy drilling rod has the advantages of low density,high specific strength,and strong corrosion resistance,but the wear resistance and thread strength are often insufficient.In actual use,aluminum alloy drilling rod need to be used with steel joints,and the steel joints mainly bear the unscrewing force.The current aluminum alloy drilling rod assembly technologies at home and abroad mainly include pre-torque method,hot assembly technology and cold assembly technology.In practical applications,hot assembly technology shows the characteristics of being more suitable for deep hole drilling aluminum alloy drilling rod.High temperature will reduce the strength of the threaded part of the aluminum alloy drilling rod body.In this paper,the actual temperature of the aluminum alloy drilling rod body and the steel joint during the hot assembly process is measured and tested.The test results show that external cool-ing can prevent the threaded part of the aluminum alloy drilling rod body from staying at a higher temperature for a long time,while the internal cooling can make the maximum temperature of the thread part reduced by about 25℃.The axial tension finite element analysis is performed on the threaded connection part,and the relationship between the maximum stress at the root of the thread and the axial tension is obtained by formula fitting.The formula calculation shows that the high temperature in the hot assembly process will cause the maximum axial pulling force of the aluminum alloy drilling rod dropped about 65 kN.From the test and simulation results,the importance of the internal and external cooling mechanism to the thermal assembly device can be seen.Combined with the previous work,the authors developed a full-size aluminum alloy drilling rod body and steel joint automatic interference thermal assembly device.