T122铁素体耐热钢析出相热力学模拟计算

Thermodynamic calculation of precipitated phases in T122 ferritic heat resistant steel

采用Thermo-Calc热力学计算软件,对T122铁素体耐热钢钒含量变化对平衡析出相及A3、A4点的影响进行了研究.结果表明,T122钢的主要平衡析出相为M23C6、MX和Laves相.当钒质量分数在0.15%以下时,将析出极少量的Z相,且其随着钒含量的增加析出量呈直线下降;当钒质量分数在0.28%以上时,将析出两种不同的MX相,随着钒含量的增加MN相的比例下降,而M(C,N)相的比例增加.钒含量的变化对M23C6和Laves相的影响甚小.钒作为封闭奥氏体元素,增加钒含量,铁素体与奥氏体的转变区域将变小.

The effect of alloying element vanadium on the thermodynamic equilibrium phases and the transformation temperatures A3 and A4 of T122 ferritic heat resistant steel were studied by Thermo-Calc software. The results show that the main precipitated phases in T122 steel are M23C6, MX and Laves phases. When the mass fraction of vanadium is less than 0.15 %, a little Z-phase precipitates, and the content of Z-phase linearly decreases with increasing vanadium content. When the mass fraction of vanadium is more than 0.28%, two different types of MX precipitate. With increasing vanadium content, the proportion of MN phase decreases, but the proportion of M（C, N） increases. The effect of vanadium content on M23C6 and Laves phases is extremely limited. As a closed austenite region element, the transformation region between ferrite and austenite becomes small with the increase in vanadium content.