Numerical Simulation Of The Stretch Bending For The New Wide Flange Stainless Steel Pillar

In recent years, with the development of economic globalization, urban traffic congestion and global warming have became increasingly serious, because of the advantages of transport capacity energy saving and environmental protection, rail was paid attention to by each country gradually. Stretch bending is a process that applying tangential tension when the profile is bending, it can make profile fit to the mold better, improve the forming accuracy, reduced defects and springback. The analysis, experiments and numerical simulation methods of stretch bending have been studied deeply all around the word currently, numerical simulation could save a lot of time and money especially, so it was used more and more widely. In this paper, numerical simulation and experiment were combined to study the new wide flange stainless steel pillar of rail vehicle, there are the main achievements:For the section distortion and opening defects done numerical simulation during the stretch bending process of the wide flange pillar, studied the influence discipline. The results showed that the standing seam height could influence section distortion, when the amount of stretching was 10%, profile standing seam height was 2 ㎜ higher than the height of the theoretical member could prove the flange straight, and the amount of opening section less than 1mm, met the production requirements, standing seam height too large or too small could lead to flange warping defects. The amount of stretching could influence section distortion, when the theoretical member standing seam height was 2 ㎜ compensated, simulated the stretch bending process when the amount of stretching were 5%,10%,15% and 20%, the results showed that the optimum amount of stretching was 10% of the length of the profile. Die clearance could influence cross section opening, simulated the stretch bending process when the die clearance were 0,0.5,1 and 2mm, the results showed that the smaller the gap, the better sectional shape.Established the stretch bending springback static implicit model of the pillar, simulated and studied the main factors of springback. The results showed that pre-elongation, post-elongation and wrap-elongation could reduce springback, pre-elongation and post-elongation had less impact on springback, wrap-elongation had the largest impact on springback, controled the amount of stretching can reduce springback effectively. Mold surface correction can control pillar profile precision effectively.Based on the best process parameters and profile design of the new wide flange stainless steel pillar for stretch bending, developed and manufactured the new stretch bending die, conducted experimental verification on CNC bending machine. After measuring, the forming pillar had high contour accuracy and without section distortion, according to the processing requirements completely, reduced production defects of the new wide flange stainless steel, reduced scrap and production costs.