硼对Ti-IF钢力学性能及再结晶过程的影响

Effect of boron on mechanical properties and recrystallization behavior of Ti-IF steel sheets

研究了硼对Ti-IF钢热镀锌板组织和力学性能的影响,并从硼对冷轧后再结晶过程影响的角度解释了硼对组织性能影响的原因。利用万能试验机、光学显微镜和透射电子显微镜对不同硼质量分数IF钢热镀锌板的力学性能、组织和析出物进行检测,采用X射线衍射仪对织构取向密度进行分析,采用电子背散射衍射技术(EBSD)对镀锌板晶界取向差分布进行分析,利用显微硬度计和金相显微镜研究了硼对IF钢再结晶过程的影响。结果表明,硼质量分数在0.000 5%以内,随着硼质量分数的提高,Ti-IF钢热镀锌板铁素体晶粒尺寸降低,屈服强度和抗拉强度提高,塑性应变比降低。硼对Ti-IF钢力学性能产生影响的原因为,硼固溶于铁素体中,抑制再结晶过程,提高再结晶温度,细化铁素体晶粒尺寸,使小角度晶界比例提高,{111}织构组分降低,从而使力学性能发生变化。

The effect of boron on mechanical properties and microstructures of hot-dip galvanized Ti-IF steel sheets was studied with universal testing machine,optical microscope and transmission electron microscope（TEM）.The reason of the influence of boron on the mechanical properties and microstructures was explained from the view of recrystallization behavior of cold rolled steel sheets with boron.Orientation densities of texture were studied by X-diffraction and misorientation angles were studied by electron back-scatter diffraction（EBSD）.Recrystallization behavior of cold rolled steel sheets with and without boron was studied with micro-hardness meter and optical microscope.The results showed that the grain size decreased,yield strength and tensile strengthincreased and plastic strain ratio decreased with increasing boron content up to 0.000 5%.Nitrogen precipitated as Ti N and boron was solid dissolved in Ti-IF steel.By adding boron,the recrystallization behavior of IF steel was suppressed and the recrystallization temperature rose,which led to the increase of frequency of low-angle grain boundaries and decrease of percentage of {111} microtexture.It was thought to be the reason of change of mechanical properties and microstructures after adding boron.