对采用Nb、Ti、Mo复合微合金体系优化设计的345MPa级耐火钢常温、高温下的力学性能进行研究。结果表明，优化后的345MPa级耐火钢有较低的屈强比与良好的高温力学性能。对普通Q235钢梁与345MPa级耐火钢梁进行不同厚度涂料涂覆和耐火测试，对钢结构防火涂料的涂覆减薄进行研究。结果表明，在同等防火涂料涂覆条件下，345MPa级耐火钢耐火极限高于普通Q235钢梁，耐火极限的提高主要由于软化温度的提高。345MPa级耐火钢在涂料涂覆减薄的条件下，满足北京2022冬奥会滑雪大跳台裁判塔二级防火设计要求。

The mechanical properties of 345MPa grade refractory steel optimized by Nb-Ti-Mo composition system at room temperature and high temperature are studied. The results show that the optimized 345MPa grade refractory steel has lower yield ratio and good high temperature mechanical properties. The coating thickness and fire resistance test on ordinary Q235 steel beams and 345MPa grade refractory steel beams are carried out. The results show that under the same fire retardant coating conditions, the fire resistance of 345MPa grade refractory steel is higher than that of ordinary Q235 steel beams due to the increase of softening temperature. Under the condition of coating thinning, 345MPa grade refractory steel meets the second-level fire protection design requirements of the ski jumping platform referee tower for Beijing 2022 Winter Olympics.

TG142.7

北京市石景山区“科技创新”专项资金项目（KYFH018）