【摘要】 通过加入不同的稀土含量对于H13钢中大尺寸碳化物的形核核心进行改质,研究了稀土对于形核核心的改质机理以及不同稀土含量对于形核核心的改质情况,并利用Factsage软件对于改质机理及完全改质形核核心的合理稀土加入量进行了理论计算。结果表明:稀土对于H13钢中大尺寸碳化物的形核核心具有良好的改质效果,随着稀土含量的增加,碳化物的形核核心的改质顺序为MgO·Al₂O₃—CeAlO₃—Ce₂O₂S或Ce₂O₃。错配度理论计算和实验表明MgO·Al₂O₃和CeAlO₃都能作为H13钢中大尺寸碳化物的形核核心,Ce₂O₂S和Ce₂O₃有效地抑制了大尺寸碳化物的非均质形核。合适的稀土加入量,MgO·Al₂O₃会被完全改质为稀土氧化物或稀土硫氧化物,达到减少H13钢中大尺寸碳化物数量的效果。热力学计算表明钢中氧含量越低,完全改质所需的稀土含量越少。更多还原

【Abstract】 The modification mechanism of rare earth on the core of large size heterogeneous nucleation carbides in H13 steel and the appropriate amounts of rare earth added were studied by adding different amounts of rare earth into the H13 steel. The Factsage software was used to calculate the modification mechanism and the reasonable amount of rare earth elements in H13 steel. The results showed that,rare earths can modify the core of large size heterogeneous nucleation carbides effectively and with the increase of rare earth content,the order of modification is MgO·Al₂O₃-CeAlO₃-Ce₂O₂S or Ce₂O₃. The theoretical calculation and experimental results showed that both MgO·Al₂O₃ and CeAlO₃ can be used as the cores of large size carbides in H13 steel,but Ce₂O₂S and Ce₂O₃ effectively inhibited the heterogeneous nucleation of large size carbides. The quantity of carbide reduces significantly as MgO·Al₂O₃ completely transformed into rare earth oxides or rare earth sulfur oxides with proper amount of rare earth added. Thermodynamic calculations showed that the lower the oxygen content in steel,the less the rare earth content required for complete modification.更多还原