316不锈钢受火后力学性能及组织变化研究

Study of Mechanical Properties and Microstructure of 316 Stainless Steel after Fire Exposure

对316不锈钢在不同受火温度、保温时长及冷却方式条件下的热处理来模拟其受火损伤的热暴露试验,进一步评定材料力学性能、相应的微观组织及晶间腐蚀情况。研究表明:在20~816 ℃受火温度下,不论保温时长及冷却方式,材料力学性能均满足要求;金相组织为奥氏体,无明显变化;晶间腐蚀试验未发现晶间腐蚀裂纹;当温度低于427 ℃时,表面颜色无明显变化;当温度在482~649 ℃时,表面颜色为黄褐色、褐色;当温度高于732 ℃时,表面呈暗红、亮红色,水冷后为蓝灰色、灰棕色。

The experiments of heat treatment were conducted on 316 stainless steel under different conditions of heating temperature,holding time and cooling method so as to simulate the influences of fire exposure on the material,from which the mechanical properties and corresponding microstructure of the material as well as the intercrystalline corrosion occurred in the material can be further evaluated.It was shown that under the fire temperature of 20℃~816℃,the requirement for mechanical properties of the material could be met regardless of the duration of insulation and the method of cooling,the metallographic structure was austenite and there was no obvious change as fire temperature increased,and no intergranular corrosion crack was found in intergranular corrosion test;when the heat treatment temperature was lower than 427℃,there was no obvious change for the surface color;when the fire temperature was under 482℃~649℃,the surface color of the material was from brown becoming reddish brown,then taupe,at last;when the heat treatment temperature was higher than 732℃the surface color of the material was dark red and bright red as it was blue-gray or gray-brown after the water cooling.