摘要
大型轧辊在铸造中很容易产生缩孔缺陷 ,本文采用Magma软件模拟分析了两种不同工艺下轧辊浇注凝固过程中的温度场变化及产生的缩孔缺陷。由模拟结果可知 ,在原始工艺条件下 ,大型轧辊在凝固过程中 ,在下辊颈和辊身结合部位易产生热节 ,导致集中缩孔。改进工艺后 ,增大下辊颈砂型的激冷能力 ,轧辊上的热节转移到了辊身上部和上辊颈中 ,在此部位产生集中缩孔。由此可以推断出 ,如在轧辊的上辊颈部位增加一个电加热冒口 ,则在辊身与上辊颈的电加热冒口间产生温度梯度 ,缩孔缺陷将转移到电加热冒口中 ,消除轧辊上的集中缩孔。模拟发现 ,金属型在凝固过程中内外壁的温差很大 ,达到 5 0 0℃以上 ,易导致铸件变形 ,因而在优化工艺设计中对上下辊颈进行了覆砂处理。
It is easy to form shrinkage defect in the casting heavy roller. In this article two kinds of processes were compared to analyze the temperature field evolution by Magma soft. From the simulated result it can be seen that the traditional process leads to the hot spot occurring in the junction of the lower part of roller and the middle part of roller, which forms the shrinkage. Through modification, we improve the cooling capability of the mold, the hot spot can be transferred to the junction of the middle part and the upper part of roller where the shrinkage is easy to occur. This result implies that if an electrical heating riser is put on the top of the roller, sequential temperature gradient will be generated along the middle part of the roller and the electrical riser, therefore the shrinkage will be transferred to the location under the electrical heating riser, the shrinkage is eliminated in the casting. Furthermore, in the simulation it is also found that during the solidification process there is temperature difference between the outer face and inner face of the die, the maximum datum is up to 500℃, which will cause the roller deformation, so in the new design casting roller, coating sand is used on the upper part and the lower part of the roller.
出处
《铸造》
CAS
CSCD
北大核心
2002年第5期297-300,共4页
Foundry
