大锻件中心压实法(JTS)锻造过程有限元分析

在大锻件生产中,中心压实法(JTS法)是压实大锻件中心缺陷的一种有效方法.但在具体的工艺实施过程中,对大锻件在JTS法锻造中的温度梯度控制,钢锭外表面的冷却控制,以及温度梯度对内部的应力应变及组织的影响缺乏足够的认识,所以很难掌握其规律.大锻件单件生产的特点,又限制了其工艺实验的可行性.本文利用有限元方法,根据温度场的特点,建立合理的边界条件及参数,计算吹风和喷水等冷却方式所对应的锻件温度场.通过热力耦合模型和刚塑性有限元分析,模拟在内外具有较高温度梯度情况下的锻件应力应变场,分析了温度梯度对锻件内部应力应变的影响规律.结果表明,锻件的温度梯度对其应力应变具有重要影响,温度梯度越大,锻件中心的等效应变和静水压应力越大,压实中心缺陷的效果越好.该模拟结果及其参数将有助于制定合理的大锻件生产工艺.

Finite element analysis of heavy forging processing with JTS method

Japan-Tefeno-Shikano method is considered as an effective method of improving the qualities of heavy forgings. But the effect of temperature gradient on strain and stress in the forging is not understood fully. So it is difficult to control the temperature gradient and the cooling parameters in forging process. The experimental research for heavy forging is limited due to the single-piece producing and large costs. The numerical simulation is alternation method for studying metal forming. The characters of the temperature field and the filed of the strain and stress were calculated by rigid-plastic finite element method. The effects of temperature gradient on the forgeability of heavy forging were analyzed. The results show that the temperature gradient has important effects on strain and stress of forging. The effective strain and the hydrostatic stress in the centre of forging increase with the increasing of the temperature gradient, which contributes to eliminating the cavity. The simulation results and its parameters can be applied in actual manufacture.