Research On Performance Uniformity Of Three-roll Skew Rolling Hollow Axle

Since hollow axles is one of the core components of high-speed trains,it must run with high quality mechanical properties.Among them,the grain size and the distribution uniformity of grain hold the key to the comprehensive mechanical properties.However,there has been little research on the uniformity of three-roll skew rolling hollow axle.So,it is considered as great significance to explore the two factors,so as to improving the comprehensive mechanical properties of rolled pieces.In this paper,SIMUFACT and three-roll cross rolling experiments as a common method,are applied to study systematically the uniformity of hollow axle with three-roll cross rolling.In this paper,the research method of combining simufact simulation and three-roll skew rolling hollow axle experiment is used to systematically study the microstructure uniformity of the three-roll skew rolling hollow axle.Firstly,in the aspect of forming,the distribution law of the speed field and displacement field of the rolled piece in different stages is studied.And through the point tracking to obtain the changes of the displacement field at different positions within the rolling stock;.Specially,the distribution law of temperature,dynamic recrystallization grain size and dynamic recrystallization volume fraction of rolled pieces in different stages is studied.In addition,point tracking,as an effective method in experiments,is probed in this paper in order to further study the variation law of temperature with time,and grain size with time.Then,the effects of feed angle,rolling temperature and roller speed on the grain size and uniformity of grain distribution are discussed by single factor test to obtain the influence rule of process parameters on the uniformity of grain formation.On the basis of that,in order to chose the optimal combination of process parameters,orthogonal test and SPSS are adopted.Exactly,the best combination of three process parameters,and the order of influence are caught,which are roller speed,feed angle and rolling temperature.At last,the relationship between feed angle,rolling temperature and roll speed on comprehensive quality index is gained respectively.In this paper,the experiment of three-roll skew rolling hollow axle is carried out.In terms of the shape quality of the rolled parts,it can be seen that the three-roll skew rolling hollow axle is of good quality,not only the surface is smooth,but also the shape and size are more accurate.It Proved the feasibility of three-roll skew rolling hollow axle.By metallographic experiments on the rolled parts,it was found that the grain size of the different parts of the experimental parts was significantly refined.The grain size was initially 2.5,and the final refinement was 5-7,which belongs to the fine grain level.The grain size of the simulated rolled part is smaller than that of the experimental part,but the deviation is basically stable between 10% and 15%.The accuracy of the simulation of the three-roll skew rolling hollow axle can also be proved.The research results in this paper will provide a theoretical basis for improving the internal quality of the three-roller cross-rolled hollow axle.By combining it with the macro forming quality research,the macro-and micro-quality of the three-roller cross-rolled hollow axle in the actual production process can be control provides relevant theoretical guidance.