关键词: 包晶钢, 连铸, 角横裂, 机理, 控制

Abstract: Transverse corner crack is the most prominent quality problem in the continuous casting process of peritectic steel. In this paper, the mechanism and control technology of corner transverse crack in peritectic steel were reviewed. The peritectic and hypoperitectic steels with carbon mass fraction ranging from 0.08 % to 0.18 % are very sensitive to cracks because of the transformation from δ phase to γ phase during the solidification process of molten steel. At the same time, the temperature for the formation of γ phase is higher, and the original austenite grains are easy to grow, so they are very sensitive to cracks. For peritectic and hypoperitectic steels containing Nb, Al and V, the second phase particles such as Nb, Al and V are easy to precipitate in the proeutectoid ferrite film of the original austenite grain boundary, which further reduces the high temperature plasticity of the steel, resulting in the occurrence of transverse corner cracks.When the thickness of proeutectoid ferrite film is more than 5 μm, the reduction of area and the plasticity of steel decrease, which is easy to cause cracks.The control technology of corner transverse crack in continuous casting slab of peritectic steel includes optimization of liquid steel compositions, mold vibration, secondary cooling conditions, chamfering mold, mold powder performance, and maintaining good equipment status of continuous caster.

Key words: peritectic steel, continuous casting, corner transverse crack, mechanism, control