Numerical simulation of seamless steel tube under cold rolling

In this paper,the numerical simulation of the forming process of seamless steel tube formed with cold rolling process was conducted by nonlinear finite element method. The distributions of the displacement,stress and strain of the whole forming process of the steel tube were obtained. According to the numerical calculation results,the distributions of the axial stress,circle stress and radial stress and three- dimensional stress states of the steel tube at different areas were drawn. The mechanism that the reduction of tube diameter influences the precision of both the diameter and wall thickness of the tube was explained according to the stress distributions. The numerical calculation results show that in the stable rolling stage,for the radial stress,the amount of the reduction of the tube has few impacts on radial stress of both inner and outer tube surface. For the hoop stress,the more diameter reduction of tube,the hoop tensile stress of the outer surface of tube will be higher,but the hoop compressive stress of the inner surface of tube will be lower. The axial stress also has the same trend which is inversely proportional to the amount the diameter reduction. Variation of residual stress appears in the circumferential direction,the small axial tensile stress and large radial tensile stress are good for the deformation of tube under rolling. Small diameter reduction is good for the tube thickness approaching to that in theory,but the diameter of tube will large than that in theory after rolling process. The results of the research can be applied to the design of both the hole shape of roll and the forming process.