Analysis Of Extrusion Process Of Two-stage Porthole Die

With the development of high-speed train,aerospace,navigation and mechanical construction industry,the demand for industrial development is increasing for thin wall,wide to thick ratio,porous,special-shaped and complex hollow aluminum profiles.In the extrusion process,the extrusion products often appear quality welding distortion and poor dimensional accuracy and various extrusion problems such as poor performance.Moreover,because the metal rheology is difficult to control,the service life of the die is low.Therefore,it is one of the key factors to get high quality,high performance and low cost to explore new methods and technologies of mold design,and further improve the flow uniformity and die life.This paper begins with small section rectangular plate as an example,in order to improve the conventional porthole die extrusion welding quality as the research object,and then by using the numerical simulation method combined with compression tests,stress field on the welding effect of welding extrusion surface in the process of location,quality,temperature field,pressure field and hydrostatic welding mould research.Then,on the basis of the A6005 tube aluminum profile as an example,using the method of combination of experimental and numerical simulation research,the double stage in the porthole die extrusion process of metal rheological behavior,velocity field,temperature field and stress variation of mold.The results show that,the temperature rise is 9.9 ?,the temperature reached 6 ? in welding chamber.Compared with the conventional porthole die,the temperature rise of the two-stage porthole die is lower than the conventional porthole die,and the temperature is 6.5?,the welding chamber temperature is only 3.8?,the welding chamber temperature distribution was more uniform;The velocity difference of the conventional porthole die,is 0.42mm/s,,and the velocity difference of the two-stage porthole die is 0.71mm/s.The standard velocity field deviation of the conventional porthole die is 0.13,and the standard velocity field deviation of the two-stage porthole die is 0.08;In the stress analysis of the die,the maximum equivalent stress of the conventional porthole die at the top of the porthole bridge is 346 MPa,and the equivalent stress distribution of the die core is even,in which the maximum equivalent stress is 433 MPa.The maximum equivalent stress at the top of the two-stage porthole bridge is 272,MPa,and the equivalent stress distribution at the mold core is more uniform than that of the conventional porthole die,and the maximum equivalent stress is 340 MPa.The equivalent stress of the porthole bridge and the die core of the two-stage porthole die is reduced by 18.7,% and 21.3,% respectively compared to the conventional porthole die.By adding a primary split die,the metal flow rate is effectively reduced,the uniformity of the metal flow is improved,and the impact force of the blank on the die is effectively reduced,,and,the,service,life,of,the die is improved,.