【摘要】 对电力火灾场景不同热输入条件下304不锈钢力学性能及微观组织开展研究，分析了最高火灾温度下与不同冷却条件下304不锈钢材料力学性能与组织演变的关联关系。结果表明：在相同温度下，保温时间对304不锈钢的力学性能影响不大；而随着温度升高，流动应力明显降低，304不锈钢的抗拉强度、屈服强度呈线性减小，1 100℃时分别降低至34.5和13 MPa,断后伸长率呈线性增加，1 100℃时增加到132%;在1 100℃,保温时间低于30 min时，以多个晶粒合并成一个大晶粒的方式逐渐长大，保温时间大于30 min后，大晶粒内部开始出现退火孪晶，晶粒和组织不再发生转变；冷却条件对304不锈钢整体力学性能影响不大，不同过火条件下抗拉强度与室温相比变化率不大于5%,屈服强度在室温至1 000℃范围下变化率不大于10%,1 100℃时，空冷及水冷条件下屈服强度分别降至81%和86%,主要归因于1 100℃时晶粒明显长大，平均晶粒尺寸达到86.1μm。更多还原

【Abstract】 The mechanical properties and microstructure of 304 stainless steel under different heat input conditions in power fire scenes were studied, and the relationship between mechanical properties and microstructure evolution of 304 stainless steel under maximum fire temperature and different cooling conditions was analyzed. The results show that the holding time has little effect on the mechanical properties of 304 stainless steel at the same temperature. The tensile strength and yield strength of 304 stainless steel decreased linearly with the increase of temperature, respectively to 34.5 MPa and 13 MPa at 1 100 ℃, and the elongation after fracture increased linearly, increasing to 132% at 1 100 ℃. At 1 100 ℃, when the holding time is less than 30 min, multiple grains merge into a large grain and grow gradually. When the holding time is greater than 30 min, annealing twins begin to appear inside the large grains, and the grain and structure no longer change. The cooling conditions have little effect on the overall mechanical properties of 304 stainless steel. The change rate of tensile strength under different fire conditions is not more than 5% compared with room temperature, and the change rate of yield strength under room temperature ～1 000 ℃ is not more than 10%. At 1 100 ℃, the yield strength under air cooling and water cooling conditions drops to 81% and 86% respectively. This is mainly due to the obvious grain growth at 1 100 ℃, and the average grain size reaches 86.1 μm.更多还原