Mn对低碳钢中先共析铁素体生长的影响

Effect of Mn on Growth of Proeutectoid Ferrite in Low-Carton Steel

采用高温共聚焦激光扫描电镜(HTCSLM)对Fe-0.15%C-0.8%Mn碳钢连续冷却时先共析铁素体的生长过程进行原位观察和动态追踪,通过对先共析铁素体生长方式和生长方向的分析,以及对先共析铁素体生长速度的定量分析,得到先共析铁素体在奥氏体晶内的生长规律。结果表明:在Mn含量为0.8%的低碳钢连续冷却过程中,先共析铁素体主要以直线方式生长,其生长方向有时发生连续两次大角度偏转,有时发生间断式偏转;不含合金元素的低碳钢中先共析铁素体的生长速度较慢,其平均生长速度为48.79μm/s,添加0.8%Mn元素后,先共析铁素体的生长速度明显加快,其平均生长速度为124.3μm/s。

The growth of proeutectoid ferrite during the cooling process of Fe-0.15%C-0.8%Mn carbon steel was observed by using high-temperature confocal scanning laser microscope （HTCSLM）, and the growth process was investigated. The growth regularity of proeutectoid ferrite plates within austenite can be obtained by analyzing the growth fashion and direction and quantitatively studying the growth rate. The results show that in the process of continuous colding of Fe-0.15% C-0.8%Mn carbon steel, the proeutectoid ferrite plates grow in the fashion of straight line style. The growth direction generates two times continuous wide-angle deflection, and generates continuous deflection. The growth velolity of the proeutectoid ferrite in the steel without Mn is slow, and the mean velolity is 48.79 μm/s, while the growth velolity becomes faster with the additon of 0.8% Mn, and the mean velolity is 124.3 μm/s.