Study On Plastic Forming Method Of Multi-section Profiled Tube

The energy saving,high precision and high efficiency production of parts are the main development direction of plastic forming,and hollow parts instead of solid parts is an effective energy saving production method,therefore,the research on plastic forming of pipe parts is more and more concerned.Multi-section profiled tube is widely used in modern industrial production,pipe plastic forming has the advantages of lightweight,near net shape,however,the literature on this aspect is relatively small.In this paper,the plastic forming method of multi-section profiled tube is studied by taking the axle shaft sleeve of the heavy truck driving axle housing as an example,this kind of axle housing is usually made of square or rectangular pipe,the end of the square or rectangular tube is changed into a circular tube,and how to change the end of square and rectangular pipe into circular section is one of the key problems to be solved.Therefore,this paper mainly studies the semi axis billet and semi shaft forming process of square tube and rectangular tube,and the following results are obtained:The square tube variable round tube need two times roll forging and one plastic roll forging.Based on the phenomenon of tube wall thickening and uneven wall thickness during the roll forging process of hollow parts,the core mold is added to improve the forming quality of the roll forging.Due to the blank theory of hollow parts roll forging,this paper based on the basis of the theory of solid parts roll forging,and then combined with the Deform simulation software to design the roll forging die and core die,through the comparison analysis with or without mandrel forming process,temperature field,wall thickness,equivalent strain,load distribution,it shows that core molding can make the pipe wall thickness uniformity,improve the forming precision,reduce material consumption and production cost,improve the stability of the roll forging,it not only beneficial to the production of light weight,but also has a certain reference value for the research of roll forging technology of hollow parts.According to the characteristics of pipe diameters ranging from the long side and short side of the rectangle,rectangular tube variable round tube need two times warmextrusion with core-die,namely one external expansion and one external contracting.Through the analysis of the influence of die inner diameter and friction coefficient on the forming effect,simulation research of the influence rule of die inner diameter,friction coefficient,extrusion speed,length of working on the maximum extrusion pressure in the process of extrusion,and find out the parameters with good forming effect and small maximum extrusion pressure,it provides an important reference value for the choice of parameters of tube extrusion simulation.Analysis of the distribution law of metal flow velocity,temperature field,equivalent strain and stroke load in the extrusion process,it is of great significance for the prediction of the location of defects in the tube production,the judgment of the rationality of the mold design and the choice of the tonnage of the equipment.Based on the structural characteristics of half shaft and blank shape,put forward four kinds of half shaft extrusion scheme,analyze the advantages and disadvantages of each scheme,determine the half shaft warm and cold extrusion process namely warm extrusion,cold shaping.Treat pipe diameter shrinkage as the research object,discuss the influence of temperature and friction coefficient on the wall thickness increment,end warping and the load.Analysis of the causes of common defects in the process of half shaft forming and puts forward the optimization scheme,such as material accumulation,flying edge,folding defect,the gap between the extrusion part and the die sizing area,and the upsetting of the fixed end.This process combines the advantages of warm extrusion and cold extrusion,it can not only meet the thickness of half shaft,but also improve the forming precision of half shaft,save material,reduce the processing,which provides a new idea for half shaft production.