Research On Pass Design And Technology Of Straight Seam Welded Pipe Formed By Roll Bending

As an important part of steel,welded pipe plays an important role in many industries.Straight seam welded pipe produced by continuous cold bending roller forming machine occupies a large proportion of welded pipe.How to improve the quality of roll bending forming is an urgent problem to be solved.In this paper,the straight seam welded pipe produced by continuous cold bending roller forming machine is taken as the research object,and the pass design and parameter optimization of welded pipe are deeply studied,which is of great significance to improve the forming quality of welded pipe.Firstly,based on the roll bending characteristics of continuous cold bending roller forming machine,the causes of quality problems in the process of welded pipe forming were analyzed,and the solutions were put forward.Combined with the pass design theory,the design of new roll pattern was completed,the amount of deformation of each pass was determined,and the rationality of roll pattern design was verified.Based on the roll pattern design,the roll design of each pass is completed,and the parameters of the roll are deduced.Based on the secondary development of Solidworks on Visual Basic platform,the parametric modeling of roll is realized,and the pass design of continuous cold bending roll forming machine is completed.Then,Marc software was used to establish the finite element model of welded pipe in roll bending process,and the accuracy of the model was verified.The forming shape change law of welded pipe in each roll bending process was obtained,and the distribution law of stress and strain in each area of cross section with forming pass was analyzed.The springback and longitudinal strain generated during the forming process were used as the evaluation index of welded pipe quality,and the parameters of thickness,diameter,deformation distribution,rolling speed,material and rack spacing on springback and longitudinal strain were obtained.Finally,based on Box-Behnken experimental design method,the response surface model of the springback distance and longitudinal strain during the roll bending process was established.The influence degree of each process parameter combination on springback and longitudinal strain was analyzed,and the mathematical regression model about springback distance and longitudinal strain was fitted respectively,and the accuracy of the model was verified.Multi-objective genetic algorithm is adopted to obtain the parameter optimization scheme,and the forming quality of welded pipe after parameter optimization was analyzed.The compensation effect of bending rebound is verified by the experiment of bending rebound,the roller bending experiment of welded pipe was completed,and the forming law of welded pipe in different areas were studied.