Abstract: The density, solidification and cooling path, phase transformation and precipitates phase of Fe-( 5 ~ 15 ) Mn-( 6 ~ 12)Al-( 0. 5 ~ 1. 0 )C low density steel are studied by FactSage and JMatPro numerical simulation software. The vertical sections of phase diagram of this system is calculated by using the FSstel database of FactSage software. Based on these vertical sections, the influence of Mn, Al and C is analyzed in the phase transformations and precipitates phase during solidification and cooling to get a diagram of the equilibrium phase-transformation path of Fe-12Mn-8. 5A1-0. 8C low density steel. The results indicate that the full-phase transformation path of Fe-12Mn-8. 5Al-0. 8C low density steel during the cooling process from 1 600 °C to 600 °C is Liquid → Liquid + Ferrite → Liquid + Ferrite + Austenite → Ferrite + Austenite → Austenite → Austenite + κ-carbide Ferrite + Austenite + κ-carbide. With the increase of C and Mn contents ， the austenite phase zone can be enlarged and the austenite can be stabilized. With the increase of Al contents, the austenite phase zone can be reduced and the ferrite can be stabilized. The precipitation temperature of K-carbide increases with the increase of Al and C content, and Al and C can promote the precipitation of carbides K-carbide precipitation. The density of Fe-12Mn- 8. 5Al-0e 8C low density steel calculated by JMatPro is 7. 05 g/cm³ , and the density of steel measured by experiment is 7. 00 g/cm³.

摘要： 借助FactSage与JMatPro数值模拟软件对Fe-(5～15) Mn-(6～12) Al-(0.5～1.0) C系低密度钢的密度、凝固及冷却路径、相变及析出相进行了研究。利用FactSage软件中的FSstel数据库对该体系的垂直截面相图进行计算,分析了Mn、Al及C元素对凝固及冷却过程中相变及析出相的影响,并得到了Fe-12Mn-8.5Al-0.8C低密度钢的平衡凝固相变路径图。结果表明,Fe-12Mn-8.5Al-0.8C低密度钢由1 600℃平衡冷却至600℃的过程中完整的平衡相变路径为:液相→液相+铁素体→液相+铁素体+奥氏体→铁素体+奥氏体→奥氏体→奥氏体+κ-碳化物→铁素体+奥氏体+κ-碳化物。C和Mn含量提高可扩大奥氏体相区,具有稳定奥氏体的作用。Al含量增加缩小奥氏体相区,具有稳定铁素体的作用。κ-碳化物的析出温度随着Al与C含量的增加而升高,Al与C均可促进κ-碳化物析出。JMatPro计算Fe-12Mn-8.5Al-0.8C低密度钢的密度为7.05 g/cm³,试验测得钢的密度为7.00 g/cm³。

关键词: Fe-Mn-Al-C 低密度钢, κ-碳化物, 析出行为, 相变, 凝固模式, 相图计算