Numerical Simulation Of Equal Channel Angular Extrution Of Fine-Grained GCr15 Alloy Material And Tribological Properties Research

The grain size within material have an important influence on macroscopic properties, grain refinement can improve the material strength, plasticity, toughness and corrosion resistance, etc. Equal Channel Angular Extrusion(ECAE) can give repeatedly severe plastic deformation to material without any significant change in cross-sectional area and ingredient so that the grain of material has been refined.The grain of commonly used bearing materials can be refined through Equal Channel Angular Extrusion treatment with a view to obtaining high-performance, long life bearing steel.This topic simulate the ECAE process of GCr15 steel,wich was based on the theories of elastic-plastic finite element method and used MSC.Marc software as a platform. The equivalent strain and extrution load's influence regularity of different curvature angleΨof the outside corner, interior angleΦand frictional coefficientμfor ECAE of GCr15 steel is obtained through numerical simulation .The simulation results indicate that the extrusion load and deformation uniformity will decrease with angleΨincreasing,meanwhile,the extrution load was divided into three stages during extrusion process,they were rapid increase stage, transition stage, stabilization stage , moreover, test specimen was also divided into three stages which cotained deformation micro cell at both ends and the central stabilization deformation zone.On the other hand,the increasing trend of maximum extrusion load will being Constantly increasing and the deformation uniformity will decrease with frictional coefficient increasing.The reason was that greater frictional coefficient brought about greater friction force between test specimen and the channel wall,as a result,the friction force have an important in impeding flowing of test specimen surface.Both extrusion load and deformation uniformity will reduce with the increase in inside curvature angleΦ,combine the two factor,it will be propitious to extrusion process and deformation uniformity after extruding when inside curvature angleΦwas 120°. The simulation and analysis that GCr15 steel was processed by means of Equal Channel Angular Extrusion will provides quantitative data reference for extrusion process optimization and production of extrusion die.The extrusion die was produced the curvature angleΦwas 120°and transition radius was 10mm according to the simulation results. Equal Channel Angular Extrusion (ECAE) processing was applied to state of high-quality hot-rolled GCr15 making use of extrusion die. Examined the influence of Equal Channel Angular Extrusion on the tribological properties of GCr15 through friction and wear properties test on pins-ring-type of MPV-1500 friction tester. The results showed that: microstructure has been refinement after Equal Channel Angular Extrusion processing, meanwhile, both the friction coefficient and wear mass loss will have a significant decline. ECAE processing GCr15 steel enhance its abrasion resistance.