Relation between Proeutectoid Ferrite and Heat Treatment

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.