环坯壁厚对铸辗连续成形的高温出模铸坯裂纹的影响

Influence of Wall Thickness of Ring Blank on Crack of High Temperature Casting Based on Casting-rolling Continuous Forming Process

环件的短流程铸辗连续成形工艺中,高温出模环坯容易在表面和边角部产生裂纹。利用Procast模拟,探讨了42CrMo离心铸造环坯壁厚对裂纹形成的影响,提出了抑制裂纹的措施。结果表明:环坯出模时温度分布不均匀、与环境温差大,导致热应力应变大,是裂纹形成的主要原因。为避免裂纹形成,宜选用外径与内径比为1.5左右壁厚的环坯。采用金属型内壁覆砂,设计模具为圆角,可降低高温环坯局部应力集中,减小裂纹敏感性。研究结果可为新工艺实现提供重要理论指导。

In the short process of casting-rolling continuous forming of ring blank,cracks are likely to occur on the surface and corners of casting ring blank at high temperature.The effect of the wall thickness of 42CrMo centrifugal casting ring blank on crack formation was discussed by Procast simulation,and some effective measures to control crack were put forward.The simulation results show that the main causes of crack formation are large thermal stress and strain,due to the uneven distribution of high initial temperature and large temperature difference with the environment,and in order to avoid the formation of cracks,thin-walled ring blank with an outer diameter to inner diameter ratio of about 1.5 should be selected.The inner wall of metal is covered with sand and the die is designed with rounded corners,which can reduce the local stress concentration of high-temperature ring blank and reduce crack sensitivity.The research results can provide important theoretical guidance for the realization of innovative processes.