Q235碳素钢不同热变形条件下退火过程的织构分析

Textural Analysis during Annealing of a Plain Low Carbon Steel Q235 Processed by Different Thermal Mechanical Processing Schedules

利用扫描电镜、背散射电子衍射(EBXD)和X射线衍射技术研究了三种方式热变形后保温时铁素体的长大行为.结果表明,回复、再结晶和长大的相对程度与第二相粒子的状态及铁素体的取向分布有关.形变强化相变产生的超细铁素体中形变储存能较低,退火时难以发生静态再结晶,而以晶粒长大为主,铁素体因第二相出现较晚而充分生长:A1温度以下纯铁素体区形变的铁素体虽然形变储存能最高,形变量最大,但第二相钉扎最明显,铁素体仅发生部分再结晶,<111>取向形变晶粒比<100>取向形变晶粒更明显地被削弱;α+γ两相区形变时,铁素体(亚)晶粒发生回复式长大,<111>取向晶粒和<100>取向晶粒有不同的再结晶倾向.

The growth behavior of ferrite grains under three different thermal mechanical processing schedules was investigated by SEM, EBSD (electron back scattering diffraction) and X-ray diffraction techniques. Results show that the relative contribution of recovery, recrystallization and grain growth was related with the status of second-phase particles and the orientations of ferrite grains. The ultra-fine ferrite grains produced by deformation-enhanced transformation had less driving force to recrystallize since less stored energy was left after deformation. They grow apparently because of the late precipitation of second-phase particles. Although ferrite deformed below A1 temperature gained the highest stored energy and strongest texture, only partial recrystallization occurred in such grains because of the effective pinning of second-phase particles. The intensity of fiber texture decreases more apparently than that of fiber texture. When deformed at α+γ dual-phase region, the ferrite grains grew in the way of recovery. The recrystallization tendencies of grains with and orientations are different.