Forming Study And Process Control Of The Multi-tube's Hydroforing

The machining technology of forging teetube is making use of circular tube blank and gains tubular components. It is an innovative technique. The machining technology of forging teetube makes the forging parts mass light, intension high, cost little and machining exactness. So it is the important aspect in 21 century in the forging and machining fields. And so the technology of tube bulging forming is being the important issue.Multi-tube hydroforming theory and mechanical analyses is introduced in this paper and an finite element simulation hydroforming model is established. Then use finite element simulation technology, applied several geometry model and model load, simulated the process of teetube bulging forming wall tee tube's bulging forming. So we get the how hydroformings measure and technological parameter affects the stress, strain, distortion and tube wall thinning. These results are the base of the teetube hydroforming technological parameter.This paper's important content and production are:1. Analysis the hydroforming theory deeply, hydroforming process and technological characteristic, deduct the values of shaped force by important-stress measure. These are the good base for teetube hydroforming process.2. Study finite element numerical simulation technology deeply. Choose reasonable parameters, such as frictional condition, contact condition, time steps and convergence criterion. Set up three-dimension elastic-plastic finite element model.3. Utilized the model above-mentioned, two different types of loading were employed: compound bulging and combined internal pressure and axial loading. The effects of friction and load patterns are examined, and deformations, stresses and tube thinning/thickening behavior in the formed component are presented. Analytical results indicated that:1) Considering not only the deforming but also the stress and strain, the compound pressure is better than the combined internal pressure and axial loading.2) We can get better results by applying least friction coefficient value, most transitional circular-angle radius value or controlling the ratio of pressure and axial load about 1:3.3) In compound bulging using ramp load patterns can achieve betterresults and load paths influence the results obviously.