Al对高碳钢连续冷却转变行为的影响

Effects of Al on the transformation behavior of high carbon steel during continuous cooling

通过热处理试验结合热力学与动力学计算,研究连续缓慢冷却过程中Al元素对高碳钢组织转变的影响。结果表明,未添加Al的高碳钢中,显微组织由马氏体及残余奥氏体组成,含1.37%Al的高碳钢中出现了体积分数为5.1%的珠光体组织,且宏观硬度降低了约0.8HRC,这是由于Al的加入能使高碳钢的共析点向高温高碳方向移动,提高了珠光体转变的临界冷却速度及相变开始温度,加速了珠光体组织的形成。

Through heat treatment tests combined with thermodynamic and kinetic calculations,the influence of Al on the phase transformation of high carbon steels during continuous slow-cooling process were investigated.The results show that the microstructure of Al-free sample consists of martensite and retained austentie,while pearlite with volumn fraction of 5.1% appears in steel with 1.37%Al addition,and the macro-hardness is reduced by about 0.8HRC.According to the analysis,the addition of Al enables the shift of eutectoid point toward high carbon content and high temperature direction,which improves the critical cooling rate and the initial temperature of pearlite transformation,and the formation of pearlite is therefore accelerated.