锻坯/模具界面摩擦对汽轮机叶片模锻成形的影响

Influence of billet-die interface friction on die forging deformation of steam turbine blade

汽轮机叶片是将蒸汽能转换成机械功的关键部件,叶片精锻是叶片锻造的发展趋势。本文利用数值模拟方法,仿真了叶片金属在锻模型腔内的流动和成形过程,论述了摩擦条件对叶片精锻成形规律的影响。在锻坯金属变形充模的3个阶段,分析并讨论了不同的界面摩擦因子m对叶片模锻成形规律和模具失效的影响。数值实验结果表明:随着界面摩擦因子的增加,克服坯料金属界面流动阻力所需的附加模锻载荷增加,叶片锻件不同区域内的最大最小温度差、最大最小等效应变差,以及最大最小等效应力差增加;与此同时,锻模型腔局部最大等效应力和最大温度也增加。

The blade of steam turbine is a key part to change steam energy into mechanical power. Precision forging of blade is the developing tendency of blade forging technology. By means of numerical simulation experiment, the flow and forming process of the blade metal in the cavity of forging die were analyzed. The influence of friction on the form ing rules in the precision forging of bade was discussed. Three phases of billet deformation in the forging blade process were emulated and the influence of the different interface friction m on the blade forming rules and the die failure were analyzed and discussed. The experiment results indicate that with the increase of the friction factor m, the accessional die forging load used in overcoming the resistance of the billet metal flowing on billet die interface and the differences between the largest and the smallest temperature, equivalent strain and equivalent stress at different areas in the billet section will be increased. At the same time, the local maximum effective stress and temperature in the die cavity will also be increased.