热轧双相钢回火后的显微组织研究

The Microstructure of Hot- Rolled Dual- Phase Steel after Tempering

研究了热轧双相钢Ｆｅ—０．０７８Ｃ—１．４４Ｍｎ—１．１１Ｓｉ—０．３８Ｃｒ经不同温度回火后的显微组织变化．透射电镜观察表明：热轧双相钢的组织中不可避免地混有少量珠光体（＜５％），它们对钢的基本力学性能并没有多大影响．本钢种２００℃回火组织中，马氏体基本不变化，为板条态，双相钢仍保持连续屈服行为；３００℃回火组织中，大量马氏体发生分解，形成碳化物，与少量珠光体交界处的马氏体首先发生分解．

The effect of various tempering tempertures on the microstrucure of a hot-rolled dual-phase steel has been investigated in this paper. TEM observation proved that pearilte (<5%) was also frequcntly observed in the microstructure. Existence of the small amount of pearlite did not affect the mechanical propertiCS of the hot--rolled dual-- phase steel. After 200℃ tempering, the martensitc microstructure remained lath, the steel also exhibited the continuous yielding behavior. Aner 300 ℃ tempering, a large number of martensite was decomposed to form carbide, the martensite near the F/P boundary was decomposed first, leading to the lose of the characteristics of dual - phase steel.