Mo对耐火钢高温屈服强度的影响

Effect of Mo on the high-temperature yield strength of fire-resistant steels

设计了一系列Mo质量分数从0.1%到0.8%的Fe-Mo-C三元模型钢.采用两种不同热处理工艺制度得到不同的组织,研究了Mo元素对耐火钢高温强度的两种强化形式:固溶强化和贝氏体相变强化.Mo可以显著提高耐火钢的高温强度,它在耐火钢中的主要高温强化机理是固溶强化.Mo质量分数不高于0.5%时,其高温固溶强化效果明显,每添加0.1%的Mo,600℃的屈服强度增量为13.71 MPa;但当Mo质量分数大于0.5%后,高温强度增幅逐渐减小.此外,贝氏体相变强化对耐火钢的高温强度也有重要影响.当贝氏体体积分数达到20%时,耐火钢的高温强度显著增加.

A series of Fe-Mo-C steels with the Mo mass fraction of 0.1%to 0.8%were designed to study the high-temperature strengthening mechanisms of fire-resistant steels with Mo addition.Two heat treatments were carried out on the Fe-Mo-C steels to investigate the strength contributions of Mo addition from solid-solution strengthening and bainite strengthening.It is found that Mo can remarkably increase the high-temperature strength of the Fe-Mo-C steels.The dominant strengthening mechanism is solid-solution strengthening.The contribution of Mo addition to strengthening the Fe-Mo-C steels shows a rapid increase with the mass fraction of Mo no more than 0.5%,and the yield strength at 600℃goes up by a significant 13.71 MPa per 0.1%Mo addition.But the high-temperature strength slowly increases when the mass fraction of Mo is more than 0.5%.Bainite strengthening also has great effect on the high-temperature strength of the Fe-Mo-C steels,and the strength increases remarkably when the volume fraction of bainite exceeds 20%.