Numerical Simulation Of Tuben Sink Drawing And Analysis Of Circumferential Residual Stress

Seamless steel tube is widely applied to ducting, machinery manufacturing, geological rig, chemical high pressure container and so on.But during the hollow sinking process, the larger circumferential residual stress is easy to cause longitudinal crack defects.This makes the steel to be a scrap, get less market less competitive, and then waste of resource severely. Along with the development of computer technology and Finite Element analysis, we can analysis the causes of circumferential residual stress in hollow-sinking process by numerical simulation and and optimize the process parameters on this. For doing this, we not only can save a lot of resources, but also have very good guiding significance for the actual production. This paper is aimed on the longitudinal crack problem which was caused by circumferential residual stress, based on the nonlinear finite element theory, and carried out a series of work:The finite element dynamic model for hollow sinking was established by APDL language of ANSYS, the stress of steel pipe and drawing force during drawing was analyzed, then the distribution of residual stress after drawing process was accounted by explicit/implicit sequential method of ANSYS. Finally, section size and residual stress after drawing and drawing force was measured. A good agreement was found between the FEM results and experimental observations.It was validated that reliability of the model and feasibility of the method.The cause of residual stress of steel pipe after drawing and the affection of all parameters of drawing for residual stress was analized, then the measures for reducing residual stress was proposed. In order to do this work, a new kind of dies which can overcome the lack of double dies through the theory of double dies drawing.Aimed on the finished pipe which size was drawed from Φ38×3to Φ30×3.In order to gain the optimal parameters of the new kind of die,the orthogonal experiment was conducted to investigated the parameters of the drawing such as semi-angle of former segment α1、semi-angle of latter segment α2、partition coefficient of two segments. In the end, the optimal parameters were simulated by FEM to show that orthogonal experiment is efficient and feasible. The maximum of circumference residualstress after drawing was reduced from229MPa to209MPa,which can decreases the possibility of longitudinal crack after hollow sinking.