The Study On The Rolling Process Of Bimetallic Seamless Steel Tube

In the metal plastic forming process, cold and hot rolling are both complicated processes,especially for bimetallic seamless steel. Researches into the forming process of rolling haveplayed significant roles in improving the precision of the wall thickness and diameter of tubeand optimizing the rolling process.In this paper, the rolling process of single mental seamless steel tube and bimetallicseamless steel tube are simulated by the finite element analysis software ANASYS, whichincluding the stable rolling stage and the stage after rolling. The simulation process involvesgeometric nonlinearity, material nonlinearity and contact nonlinearity.According to the numerical simulation, the distribution of the displacement, stress andstrain of the tube have been obtained, which involves the mechanical characteristic ofdifferent areas of tube. Based on the numerical results, the distribution of the axial stress,circumferential stress and radial stress have been drawn, which illustrates the link between theamount of diameter reduction of tube and the precision of the wall thickness and diameter oftube. Meanwhile, combined with practice, the carrying capacity of the hydraulic cylinder withthe cold-rolling seamless steel tube was studied, which aims to quantitatively analyze theinfluence of the residual stress on the cylinder.The researches have shown that the rolling process of bimetallic seamless steel tube ismore complicated compared to single mental seamless steel tube, and the distributions ofthree-dimensional stress states of both the two styles of tubes are influenced by the amountdiameter reduction of tube. The precision of the diameter of bimetallic seamless steel tube isless than single metal seamless steel tube, the small amount of diameter reduction of tube helpimprove the precision of wall thickness of single metal seamless steel. The variation of wallthickness of outer tube is more obvious than the inner tube of bimetallic seamless steel tubeafter rolling stage. The seamless steel tube after rolling process used as hydraulic cylinder hasresidual stress, which has influence on the carrying capacity of cylinder. In the hot rollingprocess of bimetallic seamless steel tube, the amount of diameter reduction of tube has moreinfluences on the precision of diameter and wall thickness of tube compared to cold rollingprocess. Based on the researches into the rolling process of tube, the effect of the distributionof stress in different areas of tube and the shape of roll on the quality of tube have beensummarized, which has guidance for the improvement of rolling process and the design ofhole shape of roll.