Finite Element Simulation Of Forging Defects Of Cr8Mo2SiV Die Steel With Large Section

With the steady development of Chinese manufacturing industry,the performance of die steel has been further required.The existence of void defects in forgings and the occurrence of cracks in forgings are a huge obstacle to the improvement of forgings' performance.In this paper,finite element simulation software ABAQUS is used to simulate the change of internal void defects of Cr8Mo2SiV cold working die steel forgings in the forging process and to predict the possibility of forging cracks.The physical simulation results are compared with the numerical simulation results,and the consistent results are obtained.The finite element model of single void located in forging center was established,the closure process and influencing factors of the center cavity were analyzed,and the stress and strain around the void were studied.The simulation results show that the ratio of height to diameter of forgings and the position of void are the main factors that influence the closure of void when the reduction rate of void is 37%in the process of upsetting.The finite element model of a single void located in a forgings difficult to be deformed was established,and the process of 2 times upsetting+4 times drawing was used in the simulation calculation.The stress and strain around the void are studied and the closure process of the void is analyzed.The simulation results show that,under the premise that the first upsetting is 50%,the deformation reduction rate of the fourth drawing is 20%,and the second upsetting is 47%under the condition that the void is closed.The key process of void closure is two upsetting processes.No cracks will occur during the 6 forging processes.The finite element model of forging with curved cutting board was established,the closure process of the void was analyzed,and the stress and strain around the void were analyzed.The simulation results show that the void can be closed with a compression rate of 31%in the process of upsetting,and there will be no cracks in the forging process.?8×15mm sample has been used to carry out a physical simulation verification test of the forging process,and the void closure process and the stress-strain relationship between forgings have been analyzed.The experimental results show that the closure is completed when the reduction rate is 29%,which is similar to the numerical simulation results of forgings of the same size.The variation trend of stress and strain is the same as that of numerical simulation.