建筑用耐火钢的高温强化机理

Strengthening Mechanism at Elevated Temperatures of Fire Resistant Steels

研究了建筑用耐火钢的高温力学性能和微观组织结构。研究发现,同普通钢相比,耐火钢获得了良好的高温性能。着色腐蚀、透射电镜(TEM)及化学相分析结果表明,铁素体+MA组织+少量珠光体的混合组织,Mo在钢中的固溶强化作用,高温下MA组织分解形成稳定的合金渗碳体以及600℃左右下MC和和Mo2C析出相大幅度增加,是耐火钢获得良好高温性能的重要原因。

The microstructure and mechanical properties of fire resistant （FR） steels were investigated. It was found that the properties of FR steels were significantly better than the plain steel at high temperature. Microstructural observation was carried out using optical microscopy, transmission electron microscopy （TEM）, and the precipitates were analysed with electroextraction trial. The results indicate that the good high temperature properties are due to the combined microstructures of ferrite, martensite-austinite （MA） island and perlite. The solid solubility of Mo in steel and decomposition of MA island at high temperature are another reason for good high temperature properties. In addition, a strong precipititation wave of MC and M2C at approximate 600 ℃ was observed which, resulted in the good high temperature properties of FR steels.