Shape Tube Continuous Roll Forming Process Simulation And The Research Of Corner Cracking

The shape tube as a significant economic section steel, which has the advantage oflow energy in cold-roll forming process, high surface quality, high dimension precision,has been widely used in the construction industry, agricultural machinery manufacturing,automobile manufacturing, large vessels manufacturing, petrochemical engineering,transportation, daily necessities and other fields. The complexity of section in coldbending forming and metal flow，more influence factors in the forming process，and morenon-accurate calculated parameters lead to poor quality of existing technology. So it hasimportant engineering significance to carry out the research of shaped tube continuous rollforming.In the case of rectangular tube, combined with the technology of continuous rollbending process， a3-D elastic-plastic nonlinear finite element analysis model ofrectangular tube roll forming depended on Marc is established with the actual roll formingprocess of7-stand.At the same time, the model is developed to simulate the seven standcontinuous roll forming rectangular tube. Compared with the results of production, thesimulating results show that the proposed model is reliable and can be applied to thenumerical simulation of continuous roll bending. Moreover, we carry on the simulation inview of the field caused by the roller bend phenomenon, and briefly analyze therelationship between tube bending, tube length and roll eccentricity.At the same time, wecarry on the simulation aiming at the roller tube bending phenomenon which is caused byadjusting the position of the roller at the scene, and also analyse the relationship betweentube bending, tube length and roll eccentric distance.Based on the established finite-simulation model, the stress and strain distributionrule is adopted in the square and rectangular tube continuous roll bending process. Itanalyses the tube billet thickness, diameter of the tube, the rolling speed and frictioncoefficient and other factors on the frame stress and strain distribution at the exit, thedistribution of residual stress are analyzed at the same time.So it determines that theangle cracking danger zones of square rectangle tube mostly concentrate in the transition area of the corner and the top and the inner corner. And using the theory of strength tocarry on the thorough analysis of the region, it gets that the cracking of processing ismostly due to the use of small angle in the rounded parts and the tube uses a largerdiameter than the tube design.Extraction is performed by simulation results of roller during rolling force and torque,and the relationship between the cumulative reduction rate and wall thickness andcumulative torque are obtained by using the regression analysis method, and the resultsare consistent with field data according to the force energy formula.Using the fixed point theory of "8" shape tube, the roller is designed and finiteelement simulation model is established. We also carry on the thorough analysis to thequality risk area of the "8" shape continuous roll forming process according to the angle ofstress and strain,and the design theory of cold-roll forming quality is better.