大口径厚壁管热挤压模具磨损

Wear of Hot Extrusion Die for Large Diameter Thick-walled Pipes

为探讨大口径厚壁管热挤压模具的磨损规律,以ASMESA-335P91钢、AISIH13钢为研究对象,结合实际试验与有限元模拟,分析温度与保温时间对模具磨损的影响情况。从模具工作条件观察得到:在金属坯料与模具接触初期,模具表面温升对磨损影响较大;在金属坯料与模具处于热平衡状态时,该状态持续时间与当前温度是影响磨损的主要因素。在金属坯料与模具接触初期得到了温度-硬度方程、温度-磨损系数方程;在热平衡状态下得到了时间-硬度方程、温度-磨损系数方程。结合Archard磨损理论,得到了适用于大口径厚壁管热挤压模具的磨损规律。最后对有限元软件进行二次开发,结果表明,预测值与高温磨损试验值基本一致,可为该类模具磨损优化设计提供理论支持。

In order to investigate the wear regularity of hot-extrusion die for large-diameter thick-walled pipe,ASME SA-335P91 steel and AISI H13 steel are taken as research objects.Combined with actual tests and finite element simulation,the influence of temperature and holding time on die wear is analyzed.Obtained from the working conditions of the mold:in the initial contact of the metal billet with the die,the temperature rise of the die surface has a great influence on the wear;when the metal billet and the die are in thermal equilibrium,the duration of the state and the current temperature are the main factors affecting the wear.The temperature-hardness equation and the temperature-wear coefficient equations are obtained at the initial contact of the metal billet with the die.The time-hardness equations and the temperature-wear coefficient equation are obtained under thermal equilibrium.Combined with the Archard wear theory,the wear regularity of hot extrusion die for large diameter thick wall pipe is obtained.Finally,the secondary development of the finite element software shows that the predicted value is basically consistent with the high temperature wear test value,which can provide theoretical support for the optimization design of the die wear.