Research On Optimization Of Forging Process For Aero-engine Casing And Die Remanufacturing By Gradient Surfacing Welding

As one of the important parts in the aeroengine,the aeroengine casing is the base of the whole engine and the main bearing part in the aeroengine.The problems of low material utilization ratio,large forming load,poor quality stability and short forging die life are often found in the manufacturing process.Therefore,it is an effective way to reduce the cost of aviation aircraft manufacturing and realize the localization of domestic aero-engine in China by making forging forming process with high stability,good performance and high material utilization rate for this type of forgings.In this paper,a certain aeroengine stainless steel casing forgings is taken as an example to solve the above problems.By using CAXA software and UG software,the 2D diagram and 3D model of aeroengine casing forging and forging die are designed,respectively.By analyzing the structure of 3D forgings,the difficulties of forging forming are preliminarily obtained.The original forging process of aero-engine casing forgings is simulated and analyzed by deform-3d finite element simulation software.The simulation results show: When the underpressure is 10 mm,the cavity of the forging die is not filled,and the position of meat shortage of forgings is the same as that in actual production;When the underpressure is 8 mm,the cavity of the forging die is filled;But the forming load is 991 mn,which is far more than the maximum pressure provided by the equipment,and the forging has a large flash edge and low material utilization;The highest temperature on the surface of the forging die is more than 650 ℃;The heat influence depth of upper and lower modes is 50 mm and 30 mm,respectively;Root corner and intermediate transition corner are stress concentration regions in the upper die,and the maximum equal-effect force values of the two regions are 1877MPa、1776MPa;The maximum principal stresses are compressive stress of 786 MPa and tensile stress of 910 MPa,respectively.In view of the problems existing in the original forging process,the optimum design is carried out from three aspects: the structure of the die,the position of the blank and the shape and size of the blank.The optimal scheme combination is obtained: Reasonable die structure,which is to reduce the slope at the middle transition corner of the upper die to 40 °,to increase the radius of the root corner to R15 and to add a flange slot in the upper die;The best blank positioning scheme,which is a smooth transition slope on the right side of the blank waist;The optimum blank dimension shape parameters,which are the 600 mm blank waist,the 60 mm waist thickness and the 80 mm end part of the blank.The weight of the billet is reduced by 40 kg and the utilization ratio of the material is increased by 15.4%.The forming load is only 478 MN,which is dropped by 51.8%.The maximum equivalent stress at the intermediate transition corner of the upper die is only 1065 MPa,which is reduced by 40.0%.The maximum principal stress is the tensile stress of 321 MPa,which is decreased by 64.7%.The maximum equivalent stress at the root corner of the upper die is only 1065 MPa,which is reduced by 40.0%.The maximum principal stress is the tensile stress of 321 MPa,which is decreased by 64.7%.Moreover,the blank is well positioned and the flash edge of the forging is evenly distributed.Finally,the gradient surfacing remanufacturing technology was adopted and the mechanical properties and microstructure of the related welding materials were tested.Based on the experimental results and simulation results,the gradient surfacing structure model of forging die is designed.The JX09,JX20,JX22 welding materials are selected as the sandwich layer,the transition layer and the strengthened layer respectively.The failure 5CrNiMo forging die is remanufactured.