不同丝径316L不锈钢纤维的再结晶行为

Recrystallization behaviors of 316L stainless steel fiber with different diameters

通过光学显微镜(OM)、扫描电镜(SEM)及X射线衍射分析(XRD)等手段研究丝径分别为12μm和22μm的拉拔态316L不锈钢纤维在退火前后的显微组织及结构特征,探究其再结晶行为。结果表明:经过拉拔变形的316L不锈钢纤维,其内部产生很高的变形储能,再结晶的驱动力增大;与22μm纤维相比,变形程度较大的12μm纤维的再结晶启动温度相对较低,这主要与纤维内部细小的晶粒以及较高的变形储能对再结晶的促进作用有关。退火后纤维内部第二相粒子的粗化以及数目的减少,使再结晶晶粒长大明显。此外,确定了12μm、22μm纤维在850℃退火时晶粒尺寸和退火时间的关系式分别为D=(01.211 t)0.182和D=(0.009 t)0.439,利用该关系式计算的热处理后的晶粒尺寸与实验结果相符。

The microstructure and structure characters of cold drawn and annealed state 316L stainless steel fibers with diameters of 12 and 22μm were systematically investigated using optical microscopy, scanning electron microscopy and X-ray diffraction. The results indicate that after cold drawn deformation, there exists high stored energy in the fibers, which enhances the driving force. Compared with the fiber with a diameter of 22μm, the fiber with a diameter of 12μm has a lower recrystallization temperature, which is closely related to higher stored energy and large amount of the second phase particles. The coarsened second phase particles and the decreasing of its amount after annealing treatment, induce the growth of the recrystallization grains. Besides, the relationships between annealing treatment time and the average diameters of recrystallization grains for both of the fibers are determined as D=（01.211t）0.182 for diameter of 12μm and D=（0.009 t）0.439 for diameter of 22μm when the annealing temperature is 850℃. When the annealing time is 30 min, the grain diameters are calculated using the formula, and the results are well agreed with the tested ones.