建筑结构用耐火耐候钢Q355FRNH耐蚀性能研究

Research on corrosion resistance property of fire-resistant and weathering steel Q355FRNH for building structure

针对钢结构是我国建筑结构的发展趋势,但对其耐火耐蚀性能要求较高的问题,通过添加Cu、Cr、Ni及其他微合金元素,采取控轧控冷工艺,酒泉钢铁集团有限责任公司开发出满足我国西北地区承受温差大、抗冬季除冰盐氯离子腐蚀且具有耐火性能的建筑结构用耐火耐候钢Q355FRNH。通过120 h和240 h干湿交替循环腐蚀试验,发现Q355FRNH钢板腐蚀点坑的大小和深度均远远小于Q355B钢板,失重率是Q355B钢板的60%;通过SEM、EDS、XRD检测分析,发现Q355FRNH钢板表面氧化层致密,其所含提高耐腐蚀性能的关键物相FeOOH较Q355B钢板高出5.5倍,腐蚀240 h后其表面仍然有一定量的FeOOH和Fe_(3)O_(4)。

In view of the problem that steel structure is the development trend of building structure,but its fire and corrosion resistance requirements are relatively high,by adding Cu,Cr,Ni and other micro-alloy elements,and adopting controlled rolling and cooling technology,the Q355FRNH building structure steel was developed by Jiuquan Iron and Steel Co.,Ltd.,which can withstand large temperature differences,resist chloride ion corrosion of winter deicing salt and have fire-resistance performance in the northwestern region of China.It was found that Q355FRNH plate had smaller size and depth of corrosion pits and lower weight loss rate than Q355B plate by the 120 h and 240 h alternate dry and wet cycle corrosion test,and the oxide layer on the surface of Q355FRNH plate was dense through analysis of SEM,EDS and XRD.The key phase FeOOH that improves corrosion resistance was 5.5 times higher than that of Q355B plate,there was still a certain amount of FeOOH and Fe_(3)O_(4) remained on the surface after 240 h corrosion.