Papers by Author: Guo Rong Wu

Abstract: The samples of cold-rolled sheets, hot-rolled plates and continuously cast slabs have been analyzed with the condition of faint-sliver defects appeared in IF steel of Pangang, and it was shown that faint-sliver defects in cold-rolled steel sheet were mainly caused by micro-cracks in the surface of strands, slag entrapment in mold during casting and inclusions in sub-surface of strand. Faint-sliver defects were controlled effectively with the technical measures, which were decreasing oxidation of ladle slag, controlling the ratio of CaO/Al2O3 in slag, extending circulation time of deoxidization and alloying in RH process, controlling the casting speed and increasing the viscosity of mold fluxes. Therefore, the ratio of downgrade induced by faint-sliver defects reduced from 10.97% to 1.0%.

Abstract: The continuous casting technologies of the new square/round billet continuous caster in Panzhihua Steel have been studied. And on this basis, the effect of process parameters of primary cooling, mold powder, secondary cooling and electromagnetic stirring (EMS) on billet quality is investigated. With these studies, the continuous casting process is optimized, and the quality of square/round billet is improved as well. Comprehensive technologies for quality control of square/round billet in Panzhihua Steel have been proposed. The results of industrial tests show that the accept rate of surface quality for square billet is 98.44%, and that is 97.42% for round billet; the comprehensive rate below level 1.0 of internal defects of center porosity, center segregation and center cracks is more than 97%, and carbon segregation index is in the range of 0.93~1.09. The quality of square/round billet can meet the requirement of consumers absolutely.

Abstract: Slab quality affects the quality of hot rolled sheet significantly. There were serious transverse corner cracks on continuous casting slab of 510L steel plate in Panzhihua Steel before. Based on this, some effective countermeasures are put forward, such as the optimization of ratio of heat flux on narrow side and broad side of casting slab and mold powder, as well as the stabilization of casting speed and working condition of caster. With these countermeasures, transverse corner cracks on continuous casting slab have been significantly reduced, and the lines and peeling defects on hot rolled sheet reduce from 30% to 0.

Abstract: There were serious transverse corner cracks on continuous casting slab of automobile frame steel plate in Panzhihua Steel before, and study on the control of transverse corner cracks had been carried out. Some effective countermeasures are put forward, such as the optimization of ratio of heat flux density on narrow side and broad side of casting slab (RHFD) and mold powder, as well as the stabilization of casting speed and working condition of caster. Industrial test shows that the transverse corner cracks on continuous casting slab have been significantly reduced, and the lines and peeling defects on hot rolled sheet have been eliminated due to the transverse corner cracks.