通过热处理试验、显微组织鉴别、截点法等手段, 重点探讨并详细总结了热处理工艺对亚共析钢先共析铁素体组织的影响规律。结果表明: 随着碳含量的增加, 先共析铁素体由块状变成网状, 数量不断减少; 冷却速度加快, 先共析铁素体一般呈网状析出; 淬火时, 随着预冷时间的增长, 先共析铁素体由断续网状向块网状以及块状过渡; 中碳钢正火时, 随着加热温度的升高, 奥氏体晶粒粗化, 先共析铁素体呈针状析出的趋势增大。

In hypoeutectoid steel, the heat-treatment process affecting proeutectoid ferrite was studied through heat treatment test, microstructure identification and the method of cut point. The results showed that proeutectoid ferrite was from blocklike to netlike with increasing carbon content, at same time the amount of proeutectoid ferrite was decreasing; proeutectoid ferrite tended to be netlike with increasing cooling rate; in quenching, with the time of forecooling increasing, proeutectoid ferrite was from interrupted netlike to block-netlike and to blocklike; when the medium carbon steel was normalizing, the grains of austenite increased and proeutectoid ferrite tended to be needlelike with the heating temperature increasing.