Effect Of Heat Treatment Process On Microstructure And Properties Of XL520 Steel And It's Bullet-proof Simulation Study

Compared with other armored materials,low alloy and ultra-high strength steel has simple machining process and the lower production cost,so it could be widely applied to armored materials.In order to study the heat treatment process of XL520 steel,the experimental steel was quenched at 850 ? to 1100 ? and tempered at 200 ? of the low temperature.The martensite morphology was observed by means of optical micrescopy(OM),scanning electron micrescope(SEM?EDS?EBSD)and transmission electron micrescope(TEM).The martensites morphology were observed from samples which were quenched,quenched and then tempered at low temperature.The microstructural sizes of martensite were measured,the relationship between each other was analyzed,and the relationship between the yield strength and the yield strength was analyzed.The control unit of the yield strength of the steel was obtained.Through the conventional mechanical properties test,and the dynamic mechanical properties experiment(SHPB),the static and dynamic comprehensive mechanical properties of the experimental steel were studied.The tensile and low temperature impact properties of finished products were observed,and the impact fracture surface was observed.The effects of different quenching temperature on Microstructure and mechanical and dynamic mechanical properties of samples were analyzed.The experimental results showed that the original austenite size PAG,the Packet structure size of martensite and the width of martensite Block structure of martensite gradually increase with the increase of different quenching temperature,but the martensitic slab width has no obvious change.There is a corresponding linear relationship between Packet and Block with PAG.With the increase of quenching temperature,the yield strength of the finished steel samples showed a downward trend,and the low temperature impact power showed an upward trend,and the dislocation density showed a downward trend.SHPB experiment was used to detect dynamic mechanical properties,and the stress-strain curve of experimental steel was obtained.Through the Joehnson-Cook constitutive model,the experimental data are processed and the constitutive equation of each heat treatment condition was calculated.The anti missile performance of the experimental steel was simulated by using the LS-DYNA simulation software under the ANSYS software module.At last,the heat treatment process of the experimental steel was optimized by combining the conventional mechanical properties data,dynamic mechanical properties data and the data of anti elastic simulation.It was concluded that the experimental steel had good armored performance when quenched at 900 ? and tempered at 200 ?.