中碳耐磨钢动态冷却条件下组织变化

Microstructure Changes Analysis of Medium Carbon Steel Under the Dynamic Cooling Condition

以中碳耐磨钢为研究对象,通过热膨胀法测定了中碳耐磨钢CCT曲线,分析了动态冷却条件下其组织变化,结果表明当冷速小于5℃/s时得到的组织为铁素体+贝氏体,随着冷速的增加铁素体的数量减少,当冷速达到10℃/s时得到的组织为贝氏体组织,随着冷速的增加贝氏体的形态由粒状贝氏体逐渐转换为板条贝氏体,当冷却速度在15℃/s～50℃/s之间时得到的组织为贝氏体+马氏体的组织。当冷速大于30℃/s的时候发生马氏体转变,生成的组织主要为马氏体组织。建议直接淬火工艺冷却速度15℃/s,冷却开始温度应该在800～850℃左右,而冷却结束温度在400～450℃左右。

It is based on the medium carbon wear resistant steel to study the microstructure changes under the dy-namic cooling condition by thermal expansion method, the CCT curve is also determined, the results shows that the ferrite ＋ bainite were obtained when the cooling rate is less than 5℃/s, with the cooling rate increase, the ferrite a-mount decreased, when the cooling rate reached the 10℃/s, the full bainite were obtained. As the cooling rate fur-ther increasing, the granular bainite transformed into the lathe bainite, when the cooling rate is 15℃/s - 50℃/s, the bainite ＋ martensite microstructure were obtained. When the cooling rate is above 30℃/s, the martensite were ob-tained. The direct quenching process is proposed in this work, the cooling temperature should start in 800 - 850℃ and end about 400 - 450℃.