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Study On Hot Extrusion Process Of Automotive Hollow Front Axle

Posted on:2018-12-11Degree:MasterType:Thesis
Country:ChinaCandidate:G Q WeiFull Text:PDF
GTID:2322330515486957Subject:Materials Processing Engineering
Abstract/Summary:PDF Full Text Request
Automotive hollow front axles withstand complex alternating stresses due to the different conditions of the road.Thus,the forming quality plays an important role in the safety of automobiles.A hot extrusion process of the automotive hollow front axle was proposed and studied in order to solve the problems that include unreasonable process procedure,process parameters and preform design,as well as non-uniform material flow and overlarge forming force.The results have theoretical and practical significance on improving the hot extrusion technology of automotive hollow front axles and promoting the technology of automotive part manufacturing in China.A kind of automotive hollow front axle was used as the research object and a combination of numerical simulation and physical experiment was chosen as the research method.This paper mainly focuses on the design and selection of hot extrusion processes,the response surface method optimization of preform design,the wear analysis of hot extrusion dies and the physical experiment.The main work is as follows:Based on the analysis of production processes of short hollow axles,two kinds of preforming schemes are designed respectively.The distribution and evolution of stress,strain,temperature,velocity and load-displacement under two schemes were studied numerically.It showed the first scheme was more reasonable.In addition,the influence of billet temperature,preheating temperature of dies and extrusion speed on the forming load was investigated.And the selection ranges of the process parameters were determined.In order to reduce the resistance while metals filling die cavities,the preform shape was optimized,so that the final part had good flowline distribution and excellent mechanical properties.Taking shape parameters and slug parameters of the preform as design variables,the central compound experiments were carried out.The response surface equations of the preform and final extrusion forces were obtained and the optimal combinations of preform shapes and slug parameters were gotten to realize the goal of reducing the forming force and improving the forming efficiency.Considering the correlation between hardness and temperature of die materials,the influence of billet temperature,die preheating temperature,extrusion speed and friction coefficient on die wear were analyzed.The influence of different parameters on surface hardness and wear rate were obtained and positions that are easy to be worn were found.The optimal combination of process parameters was obtained,and the measures to improve the service life of die were put forward.The pre-forming and final forming dies were designed and manufactured.The physical experiment of the short hollow axle was performed by using the lead.The products with good shapes and qualities were obtained.It showed the proposed process was feasible.
Keywords/Search Tags:Hot extrusion, Numerical simulation, Preform optimization, Respond surface method, Wear analysis
PDF Full Text Request
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