Abstract: Hot delivery and hot charging is effective measure of energy saving and consumption reducing in iron and steel industry. However, surface cracks of steel plates produced by DHCR can be found easily and frequently, which may be improved through suitable cooling of slab’s surface before HCR. First, it was obtained that slab’s microstructures such as fine ferrite-pearlite, granular bainite, upper bainite, lower bainite, martensite, through different cooling conditions. After that, slabs were reheated to 1200oC and rolled subsequently. All specimens’ cracks, microstructures and precipitates were analysed by means of metallographic microscope, SEM and EDS. The results show that, lower bainite was the best microstructure: the grains were fine and even, and the precipitate of Nb, V and Ti was seldom and even. No surface cracks were found in both lower bainite and ferrite-pearlite specimens after hot charging and rolling.
Authors: Banglun Wang, Fenglian Wang, and Xiebin Zhu
Keywords: HSLA Steels, Hot Charging Cracks, Microstructures, Precipitates