退火温度对车轻量化用热轧高锰钢组织和拉伸性能的影响

Effects of Annealing Temperature on Microstructure and Tensile Properties of Light-weight Hot Rolled High Manganese Steel

采用EBSD、TEM等试验测试方法分析了退火温度对车轻量化用热轧高锰钢组织和拉伸性能的影响。结果表明:经过热轧退火处理得到的铁素体与奥氏体晶粒都表现为等轴状的外形特征。当退火温度上升后,奥氏体晶粒尺寸增大,铁素体晶粒尺寸降低。高锰钢试样组织中未出现再结晶现象,在铁素体晶粒中存在很低的位错密度。拉伸过程中,高锰钢试样中的奥氏体稳定性对马氏体转变过程造成了显著影响,奥氏体的稳定性越小,其转变为马氏体的速率就越快。当真应变为0.01时,在奥氏体晶粒中形成了许多层错,未生成马氏体组织。随着应变量增大到0.1时,很多奥氏体组织转变成了马氏体。

The effects of annealing temperature on the microstructure and tensile properties of the hot rolled high manganese steel for light weight were analyzed by means of EBSD,TEM.The results show that,both ferrite and austenite grains obtained by hot rolling annealing are equiaxed.When the annealing temperature increases,the austenite grain size increases and ferrite grain size decreases.There is no recrystallization in the microstructure of high manganese steel,and there is a low dislocation density in ferrite grain.In tensile process,the austenite stability in high manganese steel samples has a significant effect on martensitic transformation process.The smaller the stability of austenite,the faster the transformation rate of austenite into martensite.When the true strain is 0.01,many faults are formed in the austenite grains,and no martensitic structure is formed.When the strain increases to 0.1,many austenitic structures are transformed into martensite.