Multi-station Hot Die Forging Process And Die Technology Research

The automatic line with multi-station hot-die forging press as the main part will become the main production mode of automobile parts forging.Based on traditional experience and theoretical calculation,process design and die design often have many problems in practical application.In this paper,DEFORM software is used to simulate and optimize the multi-station forming process of gear forging blank to ensure the quality of forgings and reduce the quality of forgings.Forging force provides support for multi-station forming of gear forging blank and die design.In this paper,the characteristics of closed hot die forging of gear blank are described firstly,and then the process flow of multi-station hot die forging of gear blank is designed according to the complexity of forging and relevant examples.That is to say,the continuous forging of gear blank at four positions is realized on a multi-station hot die forging press.The four positions are upsetting,pre-forging,final forging and punching.Refer to the relevant design criteria to design each step diagram.Then the process simulation of each station is carried out by using DEFORM-2D software.The original process parameters come from the enterprise.The simulation results show that the load of the upper die of pre-forging and final forging is too large.Through analysis of the reasons and improvement of process design,the maximum load of the upper die of pre-forging is reduced by 313 tons and the maximum load of the upper die of final forging is reduced by 239 tons.Then is the research of die technology.The overall structure of the forging die is mosaic type.The die chamber is designed according to the working steps.The contents include the cleaning air path of oxide skin,the arrangement of exhaust holes,the gap between punch and concave die,the ejection mode of forging blank,etc.Then the die simulation is carried out.The simulation indexes include equivalent stress,maximum principal stress,wear depth,temperature field distribution and so on.Initial simulation results show that the stress of the punch die in the pre-forging die exceeds the strength limit of the material,and the stress of the upper die in the final forging is worse.However,after the improvement of the structure of the pre-forging die,the stress of the die in the pre-forging position falls within the safe range,and the stress condition of the final forging dies is also improved.Finally,production test and quality control.The composition of the automatic production line for hot die forging and the means to guarantee the key technological conditions are described.During the production test,the die was preheated and the die temperature and billet temperature were measured by FLUKE thermal imager,and the forging products at different positions were obtained.Typical forging defects and die defects in production test were analyzed.The factors affecting forging quality and die life were analyzed comprehensively,and three parameters including bar preheating temperature,die preheating temperature and press slider stroke number were selected to optimize.The optimization method was: orthogonal test method combined with DEFORM simulation;the optimization results were as follows: bar preheating temperature 1190 C,pre-forging die preheating temperature 160 C,final forging die preheating temperature 180 C,press sliding.The number of block trips is 70 times per minute.Referring to the process design,die design and process parameters optimized in this paper,the enterprise adjusts and produces the forged billet according to the actual situation.The quality of the forged billet has been checked,and the appearance quality and internal organization meet the expected requirements.