Research On Continuous Roll Forming Process And The Computer Aided Design System Of Shape Tube

The shape tube as the cold formed steel, a significant economic section steel has theadvantage of high dimension precision, uniform section and high surface quality. It wasbeen used widely among various fields related national economic. Although thecontinuous roll forming process is the major produce method, as the forming complicate,the rolling pass and process design still based on the experiences. Due to all mentioned, itis very significant and practical for saving energy and materials to research the primarytheories and simulation technologies about shape tube continuous roll forming, to graspthe regulations of continuous roll forming, to predicate the demission accuracy, capabilityand optimization.The continuous roll forming process is very complicated and has several rollingpasses. It possesses typical three-dimensional non-liner character. This paper based on thecontinuous roll forming characters, fixed-point theory and topology-mapping theory,adopted double arc interpolation algorithm, established the shape tube mapping model.This model can design all the rolls applied to the shape tube continuous roll forming. Itused finite-element method to simulation several common roll holes and compared thesimulation results with the design results. The results indicated the simple cross-sectionshape tubes had small deviation and complicated cross-section had great deviation becauseof the stretch ratio uncertainty to design the hole.For advanced research to the model,a finite element analysis model of rectangulartube roll forming depended on Marc is established with the actual roll forming process ofa7-stand. Through the model, we got the simulation results was coincide with the produceresults. This confirmed the accuracy of the finite-simulation and the reliability of theestablished hole design model to design the simple cross-section shape tube.Based on the established finite-simulation model, the mental flow regulations onthe longitudinal and horizontal were adopted. The influences of rolling speed, rolldiameters,the pipe thicknesses and pipe diameters on the longitudinal and horizontalelongation were analyzed. It confirmed the pipe thicknesses and pipe diameters have a great influence on the forming thicknesses and elongation, but the speed,friction androll diameters have little influence.Aiming at the problems of corner fullness and asymmetric when rectangularforming, this paper researched the influence of roll pass, thickness and diameter onthe corner fullness and got the corner forming limitation and the varying regulation ofthickness and stretching through using multiple linear regressin methods establishedthickening ration and extension coefficientn model. Based on the continuous rollforming characters, constant volume theory and changing regulations of longitudestretching and horizontal thickness on long side, corner and short side, the extensioncoefficientn was modified and the roll pass design model were utilized.It was got the cracking danger zone was in the transition region of long side,corner and short side instead of corner by analyzing the stress and strain varyingregulations of continuous roll forming simulation. In this paper, the influence of theprocess parameters on the distribution of three-dimensional stress was analyzed.Based on the confirmation to the dangerous points using fourth strength theoryes andscene photos, small angle and large diameter was considered the main reason to thecrack in the field.With the help of simulation, the forming result and energy consuming ratio werecompared among four flat rolls, double-crook rolls and four-crook rolls, amongdifferent forming passes, and among different amounts of deformation in the samepasses. Through all the comparisons, the optical continuous roll forming process wasconfirmed.Based on the Visual Basic platform, the parametric technology and secondarydevelopment of AutoCAD, Solidworks, and Marc, the roll hole design system candraw two dimensional and three dimensional graphics, predict thedeformation,feedback,modified the hole and save the date was comed true.