【摘要】 对精加工表面磁粉探伤后出现大量微细磁痕的铸钢大链轮的原铸造工艺进行了凝固数值模拟分析 ,认为缺陷是由于顺序凝固方向上温度梯度过于平缓所致的微小缩松 ,对缺陷部位进行纵横截面的切片金相分析印证了模拟分析是正确的。据此 ,本着增大凝固方向上的温度梯度的原则用数值模拟技术进行了 15种方案的工艺优化计算并结合现场生产确定了优化方案 ,实际浇注结果表明 ,方案是成功的。用同样的原理和方法对系列轴承座的铸造工艺进行了优化并在实际中获得了成功。进一步讨论说明 ,要获得致密的铸钢基体 ,在铸造工艺设计中应注意使凝固方向上的温度梯度足够大以使液 -固界面的推进方式向逐层凝固的方式靠近。更多还原

【Abstract】 On the teeth and groove of large steel chain wheel,large number of MT thin lines were disclosed. By analysis of numerical simulation,we found that the cross solid/liquid interface was very low and the low temperature gradient will lead to micro-porosity. Then metallographic analysis through getting slices in the tangential and cross section was made to verify the numerical judgment. On the basis of increasing temperature gradient,15 foundry plots had been designed and a best one was selected to be poured,and the corresponding pouring castings showed that the selected plan was excellent. By the same principle,we succeeded in optimizing the foundry technology of bearing support. A conclusion is made that to get sound steel casting,the temperature in the solidification direction should be high enough to make the solid/liquid interface solidify in layer-by-layer solidification mode.更多还原