未分类

Convex Taper

• The section of the copper mould tube must change with the continuous contraction of the billet section, and the taper of the copper tube must be appropriate.
• If the taper is too large, it will cause extrusion of the mold to the billet shell, and it will be difficult to draw the billet by the tension straightener, which will increase the friction between the billet shell and the inner wall of the copper tube, aggravate the wear of the inner wall of the copper tube, increase the copper on the surface of the billet, and in serious cases, there will be accidents such as breaking and leakage. When the copper pipe is bent to the moon or below, because the cooling strength of the corner is greater than that of the other part, the corner is the first to leave the inner wall of the product container and generate an air gap. Under the action of the air gap in this area, a hot spot will be formed, resulting in different temperature gradients on the same cross-section. Under the action of the shrinkage stress, a bad shell crack will be formed. If the cone is too small, the air gap will increase, the effective heat flow will be less, the billet shell will be thinner, and the steel leakage accident will easily occur. In addition, if the cone is too small, the corner rotation will be intensified, and the corner cracks and divergent depressions will be easily induced.
•  The reverse taper mainly depends on the billet section, drawing speed and high temperature shrinkage of steel. Due to the non-uniformity of air gap thickness and the irregularity of longitudinal air gap formation, the single taper mold can not completely eliminate the influence of air gap, especially in the production of low-carbon clad steel. With the development of continuous casting technology, diamond taper, convex taper, multi taper, and parabolic taper mould tube have appeared. The parabolic taper mould is more consistent with the solidification shrinkage shape of the shell in the longitudinal direction, thus eliminating the adverse effects of the air gap, increasing the heat transfer effect of the crystallizer, and laying a foundation for efficient continuous casting.