Numerical Simulation And Experimental Study On Hot Rolling Of 254SMo Stainless Steel Plate

The development of super austenitic stainless steel(SASS)is a vital research direction for high-quality special stainless steels.Compared with other special stainless steels,the use of SASS can effectively reduce the application cost of the project,and therefore it can replace part of titanium-based and nickel-based alloys in industry.As a kind of SASS with high alloy content,254SMo SASS is mostly used in corrosive conditions because of its prominent corrosion resistance and outstanding comprehensive mechanical properties.However,254SMo has poor thermal plasticity and large deformation resistance,making it difficult to roll good-quality plates.For the sake of improving the production technique of 254SMO SASS,this paper comprehensively considers the complex multi physical field coupling problem in rolling,and uses a combination of academic analysis,numerical modeling and experimental research to deeply study the hot deformation behavior and rolling process of 254SMO SASS,which provides some guidance for the actual hot rolling production.The main research contents and conclusions are as follows:The thermal simulation compression experiment under isothermal constant strain rate was used to successfully obtain the material flow stress change value of 254SMo SASS in the range of temperature and strain rate are 900-1100?,0.005-5s^-1 respectively.The study analyzed the influence of factors such as temperature and strain rate on material properties.Studies have shown that the peak stress of 254SMo SASS deformation at high temperature shows a downward trend with the increase of temperature when the strain rate is low,and the unimodal characteristic of the rheological curve becomes obvious.The high-temperature constitutive model of 254SMo SASS was established,the deformation activation energy of 254SMo SASS was calculated to be 546k J/mol,and the accuracy of the constitutive equation in the form of exponential function can reach 97.5%.The microstructure of 254SMo SASS after compression was analyzed,it was found that the peak stress of 254SMo SASS gradually decreases with the increase of temperature under the condition of low strain rate because dynamic recrystallization plays a major role.To obtain a rolling force calculation method with high calculation accuracy and short calculation time,the SIMS empirical formula was used to calculate the 254SMo SASS plate hot rolling force;the ABAQUS was used to establish a 254SMo 3D thermal-mechanical coupling FEM to analyze the rolling process Equivalent stress distribution law,the change law of rolling force under different rolling process parameters was obtained;Based on the FDM,a temperature set model of the sheet hot rolling process considering multiple factors such as radiation,convection,and conduction is established,and the rolling force calculation model is obtained based on the arc-shaped micro element deformation in Orowan deformation zone.Using C++language to compile the program,the calculation software of rolling force and rolling temperature for 254SMo SASS plate hot rolling based on FDM was developed.By comparing the measured data and simulation data of 254SMO SASS plate rolling force under three reduction rates of 30%,35%and 40%and two heating systems of 1150?and1250?,it can be seen that the simulation rolling force error of ABAQUS is lower than 10%,which has high calculation accuracy,but the calculation time is long;the rolling force error of SIMS empirical formula is about 20%which has low calculation accuracy.Based on the FDM,the error of rolling force is about 12%.Considering the error precision,calculation time and human-computer interaction,the rolling schedule calculation software based on finite difference method can provide efficient and accurate guidance for the formulation of 254SMO stainless steel rolling process.