Microstructure and Properties of New Type Bainitic Steels at Low Temperature Tempering

Through studying the microstructure and mechanical properties of a kind new low alloy bainitic steel under different tempering processes, the temper characteristics of such steel can be obtained. The results show that, after normalizing and low temperature tempering, the microstructure of the bainitic steel has higher strength, toughness, good welding property, higher tempering resistance and better working properties, which consists of bainite ferrite and retained austenite; and its microstructure transforms into the typical bainite from new type of bainite with the increase of tempering temperature. Temper brittleness occurs at 500 ～600 ℃, the reason of which is related to bainite ferrite and retained austenite decomposing for carbide.