| The microstructure evolution during the thermal deformation has an important influence on the properties of steel,and is affected by many processing parameters.This paper takes 10#steel as the research object,which is a typical low-carbon steel with lower strength and hardness,and better plasticity and toughness.In recent years,because of the rapid development of the construction industry and the automobile industry,10#steel has been widely used and the requirements for materials steel products were higher.At present,the method of controlling the microstructure of the material during thermal processing was often used to obtain achieve higher quality.Therefore,it is necessary to study the law of microstructure evolution during the material forming process.In this paper,the grain growth experiments,single-pass compression experiments and double-pass compression experiments were carried out on the Gleeble-1500 thermal simulator using 10#steel samples by physical simulation research technology.The effect of recrystallization and grain growth mechanism on the microstructure and properties of this steel were studied,combined with the experimental results,the corresponding mathematical models were established.The main contents are as follows:The grain growth experiment was designed to obtain the microstructure of 10#steel under high temperature,and the effect of holding time and holding temperature on grain growth behavior were studied.Results show that the grain size of 10#steel increases exponentially with the increase of deformation temperature;and with the increase of holding time,the grain size first increases and then stabilizes.In addition,the Sellars mathematical model of 10#steel under high temperature conditions was established,and the fitting effect was good.The single-pass compression experiment was designed to study its dynamic recrystallization behavior.Combined with the flow stress curves of the steel,the strain-compensated Arrhenius constitutive equation was established,which can be used to predict the thermal deformation behavior of the test steel;and the processing maps under the strain conditions of 0.2,0.4,0.6,0.8 and 1.0 were established,the stable zones and instability zones under the conditions were analyzed,combined with the microstructure characteristics,it can be clearly seen that the best processing area of the steel is 1100-1175?and1.35×10-1-6×10-1s-1.Finally,in order to better describe the dynamic recrystallization behavior,the critical strain model,dynamic recrystallization kinetics model and grain size model were established,and the effect of fitting was good.According to the obtained critical strain for dynamic recrystallization under different conditions,the double-pass compression experiment was designed to study the meta-dynamic recrystallization and static recrystallization behaviors of 10#steel.Combined the flow stress curves and the microstructure morphologies,the influence of different processing conditions on its recrystallization behavior were analyzed.In addition,the kinetics model and grain size model of the corresponding recrystallization mechanisms were established,and the calculation results of these models were proved to be accurate. |
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