汽车油管螺栓挤孔冲头磨损分析与优化

Wear analysis and optimization on hole extrusion punch for automotive oil pipe bolt

针对汽车油管螺栓孔成形时挤孔冲头受力大、表面磨损严重的问题,借助Deform-3D软件对油管螺栓的挤孔成形过程进行数值仿真,对冲头表面的磨损情况进行预测和优化。对油管螺栓原材料(40CrNiMoA钢)的常温力学特性进行了研究,并拟合得到了J-C本构方程,从而为仿真试验结果的准确性提供了保障;研究了冲头材料(M2钢)和涂层材料(TiAlN)在不同温度下的硬度及磨损系数的变化规律,建立了可靠的磨损模型;比较了3种不同结构冲头的磨损、受力和温度变化等情况,确定了更利于金属流动的冲头结构;研究了表面涂层技术对各冲头表面磨损的影响,并对冲头寿命进行了预测。研究结果表明:锥面冲头的效果最好,使用寿命最长,并且经过涂层处理后,冲头寿命提高至原来的2.08倍。

Aiming at the problems of heavy force and serious surface wear of extrusion punch during the forming of automotive oil pipe bolt hole,the forming process of hole extrusion for oil pipe bolt was numerically simulated by Deform-3D software to predict and optimize the wear condition on the surface of punch.Then,the mechanical properties of raw material for oil pipe bolt(40CrNiMoA steel)at room temperature were studied,and J-C constitutive equation was obtained by fitting,which provided guarantee for the accuracy of simulation test results.Furthermore,the change laws of hardness and wear coefficient of punch material(M2 steel)and coating material(TiAlN)at different temperatures were studied,and a reliable wear model was established.By comparing the wear,force and temperature change of three kinds of punches with different structures,the punch structure which was more conducive for metal flow was determined.Finally,the influence of surface coating technology on the surface wear of various punches was studied,and the service lives of punches were predicted.The results show that the cone punch has the best effect and the longest service life,and the service life of punch is increased to 2.08 times of the original punch after the coating treatment.