Influence Of Die Wear On Center Porosity In Cross Wedge Rolling Part

The principal problem of cross wedge rolling technology in application is that deformed material is inclined to have the defect of porosity in its center. We have certain knowledge about the damage rule of center material through existing theoretical analysis. Damage of center material can be controlled efficiently and qualified rolling parts can be assured by choosing appropriate deformation parameter when designing dies according to the degree of deformation. It's been discovered in production that the probability of forming porosity or holes in the center of rolling parts is obviously increased after the dies are worn out. And worse it will influence the quality of products or interrupt normal production. We have no intensive analysis and knowledge on the problem with existing theory, simulation and experiment so that it is difficult to control the quality of products.According to the above problems, this paper analyzes the typical cross wedge rolling technique and obtain computation model of wear on cross wedge rolling dies and simulates the die wear in different parameters. Result reveals that abrasive depth will increase when forming angle, broadening angle, forming degree increase and abrasive depth will decrease when temperature and hardness increase.Effective stress ,tensile stress in the direction of axial and tangential stress increase when CWR die is abrasive ,the effective strain ,tensile strain in the direction of axial and tangential strain also increase with the die wear. The press varies not obviously. The damage of the piece centre increases sharply.By the experiment of simulating the state of die wear, elevating the end of the CWR die. The experimental results show that elevating molds with a high degree increase the probability of central porosity. the deforming degree variation is the leading factor that cause central porosity when the die is abrasiveThe study of the wear on dies and the influence pattern of wear on quality of rolling parts in this paper will result in incisive knowledge on cross wedge rolling technology. And it is important in theory and in practice on revealing the leading factor among the changed parameters caused by abrasion, which causes central porosity in central material. More it will guide repairing abrasive CWR dies.