Influence Of Heat Treatment And Forging Process On Microstructure And Properties Of H13 Hot-working Die Steel

H13 hot work die steel is an important steel grade in the mold steel category.It has good heat strength,red hardness,high toughness,hardenability,fatigue resistance,and good high-temperature impact resistance.It is widely used in aluminum die casting molds for light alloys such as magnesium and zinc,aluminum alloy extrusion dies and hot forging dies.In the service process,the hot work die steel needs to withstand the stress caused by impact,wear,thermal fatigue,plastic deformation,and rapid cooling.If the H13 hot work die steel is improperly treated in the heat treatment and forging process,resulting in economic loss or accidents.The genetic properties of the metal material structure accompany the entire process of heat treatment.Therefore,we need research on homogenization annealing treatment of the ESR steel ingot before the forging process,studies the influence of heat treatment and forging process parameters on the microstructure and properties of the H13 hot work die steel,revealing the thermal processing technology on the material properties and organization.It has important theoretical and practical significance for guiding the actual forging engineering.Based on the actual production status,this paper uses Gleeble thermal compression experiments and systematically studies the effects of different treatment processes on the microstructure and properties of materials.The main research work is as follows:The effects of homogenization heat treatment temperature and time on homogenization effect.microstructure and impact properties were studied.Setting 2×3 orthogonal test of homogenization of H13 ESR ingot,after forging,normalizing and spheroidizing annealing of the homogenized sample,analyzing the diffusion of the elements,conducting the impact performance experiment,revealing the homogenization temperature and time on the material organization,the influence of element diffusion and impact resistance.Considering the experimental conditions,the optimal homogenization annealing process was determined to be 1280? × 10h,In this paper,1280? × 10h homogenized H13 steel is used as material for a hot compression test,We can obtain the true stress-strain curve of H13 steel when the deformation temperature between 950?1150?,deformation rate is 0.1?10 mm/s.The Arrhenius constitutive relationship model and thermal processing diagram were established.The established constitutive model can accurately describe the high-temperature rheological behavior of H13 hot work die steel.According to the thermal processing map,at 60%deformation the optimum forging temperature range of H13 is 1050?1125?,strain rate interval is 0.1?2s-1?Different normalized processes were used homogenized and forged materials.The effects of normalizing temperature,normalizing holding time and normalizing time on the microstructure of the material were studied experimentally,and the optimal normalizing treatment parameters were obtained.On this basis,studied the spheroidizing annealing process of h13 hot work die steel.The distribution and shape of spheroidal carbides were analyzed by SEM scanning electron microscopy.At the same times,the effects of different temperatures and processes on the spheroidization state were studied.Analyzed the spheroidization process of granular carbides,and the optimal normalizing and spheroidization annealing process parameters were finally obtained.In this paper,the finite element simulation model of H13 hot work die steel multi-directional forging process is established.Based on the established H13 constitutive model,the metal flow law of H13 steel in multi-directional forging process is simulated,the forging temperature and deformation are analyzed.The effects of velocity and multi-directional forging on the damage value,maximum principal stress,equivalent stress,equivalent strain and load of the material.