Abstract: After cold-rolled deformation of 430 ferritic stainless steel at room temperature with a 55% reduction, the annealing treatments were carried out at 800, 850, 900, 950, and 1000℃ for 15 min, followed by in?situ tensile and nanoindentation tests. The microstructure and mechanical properties of 430 ferritic stainless steel were studied by field emission scanning electron microscopy (SEM), electron backscattering diffraction (EBSD) and transmission electron microscopy (TEM). The results indicated when the annealing temperature increased from 800 to 850℃, the recrystallization proportion of the cold-rolled microstructure of the sample gradually increased, the recrystallization proportion increased from 66% to 68%, and the average grain size decreased significantly, from 9.23 μm to 8.07 μm. At this time, the microstructure of the sample was mainly affected by grain refinement, and the strength and plasticity of the sample were improved to a certain extent. The hardness also showed a certain degree of improvement. When the annealing temperature increased from 900℃ to 1000℃, the recrystallization ratio of the cold-rolled specimens increased from 71% to 89%, the average grain size increased by about 1.5 times, the dislocation density decreased significantly, the strength of the specimens decreased while the plasticity increased, and the hardness decreased significantly. When the sample was annealed at 850℃, the grain size in the structure is small and uniform, the yield strength reached 882 MPa, the elongation reached 17.5%, and the hardness value wass 2.08 GPa, indicating good microstructural and mechanical properties. Therefore, the optimal annealing process of 430 ferritic stainless steel was held at 850℃ for 15 min.

Key words: ferritic stainless steel, recrystallization, dislocation density, mechanical property

摘要： 采用55%的压下量对430铁素体不锈钢进行室温冷轧变形后，分别在800, 850, 900, 950, 1000℃进行保温退火处理15 min，采用原位拉伸和纳米压痕测试，并且利用场发射扫描电子显微镜(SEM)、电子背散射衍射(EBSD)、透射电子显微镜(TEM)等技术手段研究了430铁素体不锈钢的微观组织和力学性能影响及其规律。结果表明，当退火温度由800℃升高至850℃时，试样冷轧组织再结晶率逐渐提高，由66%提高至68%，平均晶粒尺寸明显减小，由9.23 μm减小至8.07 μm，此时试样组织主要受到了晶粒细化的作用，试样强塑性提高。当退火温度从900℃升高到1000℃时，冷轧组织再结晶率进一步提高，由71%提高至89%，平均晶粒尺寸增大约1.5倍，位错密度显著降低，强度下降，塑性增强，硬度明显降低。样品在850℃退火时，晶粒细小均匀，屈服强度达到882 MPa，伸长率达到17.5%，此时硬度值为2.08 GPa，具有较好的微观组织及力学性能，因此在850℃保温退火15 min为430铁素体不锈钢的理想退火工艺。

关键词: 铁素体不锈钢, 再结晶, 位错密度, 力学性能