高速列车用A286高温合金六角头螺栓头部热镦成形参数优化

为提高六角头螺栓头部热镦成形工序的合格率,选取影响成形质量较大的加热温度、热镦速度、摩擦系数3个因素设计了正交试验,并利用有限元分析软件Deform-3D建立了热镦过程的热力耦合数值模型,用数值模拟的方法对热镦后坯料的等效应力、等效应变、损伤值和成形载荷这4个目标参数进行多目标优化分析,优化设计了A286高温合金六角头螺栓头部热镦成形的工艺参数。数值模拟结果表明:与厂家原有方案相比,当工艺参数优化为加热温度为1050℃、热镦速度为60 mm·s-1、摩擦系数为0.3时,各目标参数均有所改善,可大大提高工件的合格率及生产效率。采用经优化的热镦工艺参数组合进行生产试验,结果显示:螺栓头部成形效果好,满足该工序质量要求。本研究为实际生产提供了理论依据。

Optimization of hot upsetting forming parameters of A286 superalloy hexagonal headed bolt head for high-speed train

In order to improve the qualification rate of hot upsetting forming process for hexagonal headed bolt head,the orthogonal experiment was designed by selecting three factors,namely heating temperature,hot upsetting speed and friction coefficient,which have great influence on the forming quality.The thermo-mechanical coupled numerical model of hot upsetting process was established by using finite element analysis software Deform-3D.By means of numerical simulation,the equivalent stress,the equivalent strain,the damage value and the forming load of billet after hot upsetting were analyzed by multi-objective optimization method.The technological parameters of hot upsetting forming for A286 superalloy hexagonal headed bolt head were optimized.The numerical simulation results show that,compared with the original scheme of manufacturer,when the technological parameters are optimized as the heating temperature of 1050℃,the hot upsetting speed of 60 mm·s-1 and the friction coefficient of 0.3,the target parameters are improved,and the qualified rate and production efficiency of workpiece can be greatly improved.The production test was carried out with the optimized combination of hot upsetting process parameters.The results show that the forming effect of bolt head is good and meets the quality requirements of the process.The research provides a theoretical basis for actual production.