The Research For As-cast42CrMo Steel Shaft Microstructure Of Radial Forging

Forging technology has been widely used in machinery, aviation, aerospace,mining, construction and other fields, It is an important technology in metallurgicalproduction. At present, forging technology has been developed to the stage ofmechanical automatic forging. The automatic forging method includes free forging anddie forging, and radial forging belongs to free forging with more advantages of goodsurface quality, machining allowance, high size precision, net shaping and etc. Basedon the review of the related literature, there were a few researches on the radial forgingmicrostructure. Therefore,42CrMo steel shaft structure of cast of radial forging,including the law, was studied.The as-cast42CrMo steel from physical simulation and finite element simulationwere studied in this paper. Based on the data from the physical simulation experiment,the flow stress model and recrystallization model of the material were established. Thenumerical simulation of radial forging cast42CrMo steel shaft in different forgingconditions was carried out with the help of the finite element simulation software ofDeform-3D.The single pass compression test on the material was carried out with the hotcompression simulation test, and the data of compression test was attained. The flowstress behavior of the material was developed, then the Zener-Hollomon Parameterswas attained, and the flow stress constitutive equation, percentage of dynamicrecrystallization model and hot processing map were founded.The quantitative analysis of the material was carried out through metallographictest, thus the average grain size of as-cast42CrMo steel under different deformationconditions was attained, and the size model of dynamically recrystallized grains of thematerial was established by referring to the Zener-Hollomon parameters.The single pass compression forging simulation and radial simulation werecarried out with the Deform-3D software. The single pass compression simulation program and hot compression simulation test scheme were same. The result from thesingle pass compression simulation program was compared to the result of themetallographic experiment to verify the accuracy of the established dynamicrecrystallization model. With the validated model, the numerical simulation of radialforging steel shaft was carried out in order to study the iInfluence on the distributionlaw of the recrystallized grain structure under different pull speeds and reductionconditions.Through the simulation of as-cast42CrMo steel shaft in radial forging, theconclusion was drawn that forgings of the same diameter, with the certain pull speed,the thickness of dynamic recrystallization layer inside the forgings was thickened withthe increase of the reduction and with the certain reduction, the thickness of dynamicrecrystallization layer inside the forgings was thinned with the increase of pull speed.