滑动叉热锻模失效分析和解决措施

Failure analysis and solution measures of sliding fork hot forging die

热锻模具在工作过程中承受交变的热应力和机械应力的综合作用,易因磨损、开裂和塑性变形等失效。针对某型号滑动叉热锻模寿命低的问题,根据其失效形式分析了失效的主要原因,发现终锻模的失效部位主要在冲孔凸台端面,热裂纹呈放射状,冲孔凸模具有一定程度的塑性弯曲。理论分析和数值模拟结果显示,冲孔凸模的端面因长时间接触炽热的坯料而导致温度升高,其强度和刚度降低,且长时间在热应力和接触应力的共同作用下,端面产生裂纹,并发生一定程度的弯曲。通过控制坯料的镦粗量、提高凸台的刚性、优化冲孔凸台的高度、改善材料流动的合理性,以及使用3D打印技术并采用红硬性高的材料制造冲孔凸台,使模具寿命得到了明显提高。

The hot forging die is subjected to the combined action of alternating thermal stress and mechanical stress during the working process,and it is prone to failure due to wear,cracking and plastic deformation.Aiming at the problem of low service life of hot forging die for a certain type of sliding fork,the main causes of failure were analyzed according to its failure modes.It is found that the failure position of final forging die is mainly on the end face of punching boss,the hot crack is radial,and the punching boss has a certain degree of plastic bending.Theoretical analysis and numerical simulation results show that the long-term contact of the end face of the punching punch with the hot blank leads to an increase in temperature and a decrease in strength and stiffness.Under the combined action of thermal stress and contact stress for a long time,the end face cracks and bends to a certain extent.By controlling the upsetting amount of blank,improving the rigidity of boss,optimizing the height of punching boss,the rationality of material flow,and using the 3D printing technology and the material with high hot hardness to manufacture the punching boss,the die life is significantly improved.