Study On The Extrusion Forming Process And Microstructure And Properties Of 40CrNi2MoE Steel Shaft Forgings For Aviation

In China,40CrNi2MoE steel is mainly used in aircraft main load-bearing components or as fasteners.However,currently,there is a lack of experience in using40CrNi2MoE steel for aviation transmission shafts through medium temperature tempering treatment in China.As one of the key core components of aviation transmission systems,the comprehensive performance of shaft components is closely related to the safety of aviation engine operation,and the comprehensive performance of materials is largely determined by their microstructure changes.Therefore,it is of great significance to conduct research on the forming process and microstructure performance of 40CrNi2MoE steel aviation shaft.This article focuses on the study of high-purity 40CrNi2MoE steel.By conducting thermal simulation compression experiments on high-purity 40CrNi2MoE steel,the rheological stress behavior and dynamic recrystallization behavior were studied.Through mathematical calculations,the rheological stress constitutive model,dynamic recrystallization critical stress and peak stress model,dynamic recrystallization percentage model,and grain size model of high-purity 40CrNi2MoE steel were constructed.A brand new database of 40CrNi2MoE steel was constructed in Deform software,and the extrusion process of 40CrNi2MoE steel shaft forgings was simulated and calculated using Deform software.By simulating the extrusion process with different extrusion parameters and comparing the strain field,temperature field,and dynamic recrystallization degree of the forging after extrusion,the shape of the extrusion mold and billet was designed,and a set of suitable extrusion parameters were selected and tested for the shaft forging.After extrusion,the tensile property,impact property and microstructure of each part of the forging were tested.Through the test data,it was verified that the forging produced under the extrusion parameters met the use requirements.A study was conducted on the low cycle fatigue performance of high-purity40CrNi2MoE steel tempered at different temperatures.Through the study of its low cycle fatigue failure characteristics,in order to obtain better and more stable low cycle fatigue performance,it was decided to use 440 ℃ 4h tempering as the heat treatment method for forgings.A systematic study was conducted on the low cycle fatigue performance of high-purity 40CrNi2MoE steel tempered at 440 ℃ for 4 hours,and a Manson Coffin life model,Ostergen energy life model,and three parameter life model were constructed to better predict the low cycle fatigue life of the material.