材料期刊网

本文以新型的含铌高强细晶IF钢为研究对象，在实验室进行了热轧、冷轧以及轧后模拟连续退火实验。通过微观组织观察可以发现化学成分的改善、轧制及退火工艺的控制不仅可以使这种钢具有细小的晶粒，而且存在大量细小的析出物Nb（C、N）；同时晶界附近析出物非常稀少，称之为PFZ带（晶界无析出物区），且仅存在于晶界的一侧。实验结果表明由于Nb系析出物非常细小以及晶粒细化作用使实验钢具有较高强度和良好的延伸率；而PFZ带的存在，这种钢具有较低的屈服强度。与传统的IF 钢相比，实验钢具有晶粒细小、屈强比低、延伸率良好且塑性应变比r值较高的特点。

The hot rolling, cold rolling and simulative continuous annealing experiments were carried out in the laboratory on the base of new type SFG HSS (super fine grain, high strength steel sheet). The microstructure observation results show that the microstructure of this new type steel contains not only very fine ferrite grain but also Nb(C, N) precipitates by improving chemical composition, controlled rolling and controlled annealing. The PFZ zone is free of precipitate called Precipitated Free Zone on the one side of the grain boundary. The results show that the SFG steel has very high tensile strength and good tensile elongation by fined Nb,Ti(C, N) precipitates and very fined ferrite grain. On the other hand, it also has very low yield strength by the formation of the PFZ. Contrast to the conventional IF steel, the SFG steel have the characters of super fine grain, high tensile strength, low yield strength/tensile strength rate, good elongation and high r-value .