A Slab Narrow Surface Convex Surface Mold and Its Design Method

Abstract

The present invention proposes a narrow-surface convex curved surface crystallizer of a slab and a design method thereof, which belongs to the field of steel continuous casting. The narrow-surface copper plate of the mold of the present invention has a wide upper opening and a narrow lower opening structure, and the thickness of the upper and lower opening copper plates is the same; The inner surface of the narrow-faced copper plate has an inner convex curved surface structure, which is composed of a convex curved surface in the middle area and a convex curved surface in the edge area; the slab narrow-faced crystallizer designed by the present invention can fully compensate for the shrinkage of the blank shell in the crystallizer. , effectively suppressing the concentrated distribution of the mold slag film and air gaps in the areas near the corners of the billet shell, thereby achieving rapid cooling of the corners of the billet, refining the grains of the initial solidification structure at the corners of the billet, and dispersing the carbon nitride in the crystal and within the crystal. boundary precipitation, fundamentally inhibiting the occurrence of corner cracks in the microalloy steel continuous casting billet; using the slab mold taper designed in the present invention can also effectively eliminate the "hot spots" in the areas near the corners of the billet shell's wide and narrow surfaces, realizing the billet The shell grows uniformly within the crystallizer.

Description

technical field [0001] The invention belongs to the field of steel continuous casting, and in particular relates to a slab narrow surface convex curved crystallizer and a design method thereof. Background technique [0002] The microalloying technology of steel developed rapidly in the 1970s. Adding microalloying elements such as Ti, Nb, B, and V to steel can greatly improve the strength and plasticity of steel, which has been widely used in modern steel production. However, adding microalloying elements to steel greatly increases the crack sensitivity of the slab. Improvement, continuous casting production of this type of steel slabs often have corner transverse crack defects; it has been clarified that the main reason for the frequent occurrence of corner transverse cracks in micro-alloy steel continuous casting slabs is: in the existing continuous casting process and cooling In this mode, the microalloying elements in the steel are easily combined with C, N and other ele...

AI Technical Summary

Problems solved by technology

However, this taper design does not take into account the fact that the corners of the billet shell shrink more than the central area of ​​the narrow face during the solidification process of the actual shell. Effectively eliminate the concentrated distribution of mold slag film and air gap in the corner area of ​​the billet shell;

[0005] The patent of invention with the publication number CN104117641A discloses a method and device for obtaining the continuous taper of a segmented reference parabola of a crystallizer, which realizes a better contact between the casting slab and the copper plate of the crystallizer; however, the continuous tapered crystallizer designed by this method is also The fact that the corner shrinkage is larger than the central area of ​​the narrow face during the solidification process of the actual billet shell is not considered;

[0006] The articles titled "Study on Taper of Copper Plate in Slab Mold" and "Study on Taper of Copper Plate in Baosteel Slab Mold" studied the shrinkage law of the slab shell along the center direction of the width and narrow face of the mold, and proposed the setting of the wide face of the mold. Small taper and narrow face set different taper viewpoints according to different casting speed conditions; this study did not change the taper structure of the narrow face of the crystallizer, but only adjusted the taper size based on the original linear narrow face mold, so it still cannot cater to the actual billet shell Dynamic solidification shrinkage characteristics along the height direction;

[0007] The invention patent with the publication number CN1559722A discloses a technology for online control of the taper of the narrow surface of the slab crystallizer based on the ratio of heat flow between the narrow surface and the wide surface of the mold; this technology is only based on the existing linear mold copper plate structure. The size of the face taper also cannot overcome the problem that the traditional crystallizer copper plate cannot meet the dynamic solidification and shrinkage characteristics of the billet shell;

[0008] The invention patent with the publication number CN102328037A discloses a self-tapered slab chamfering crystallizer which effectively eliminates the transverse cracks at the corners of the slab; The taper design of the chamfered surface is realized, and the taper in the middle area of ​​the copper plate of the narrow mold is appropriately increased linearly, which is equivalent to the overall adjustment of the taper of the traditional straight-line narrow surface in terms of use effect, and it is also unable to overcome the taper of the narrow mold surface Insufficient compensation for billet shell shrinkage in the upper part and excessive compensation in the lower part;

[0009] The invention patent with the application number 201310356316.X discloses a method for designing the taper of the slab crystallizer based on the dynamic shrinkage characteristics of the billet shell and the distribution behavior of the mold slag film and the air gap. Through this taper, the copper plate can effectively cater to the solidification and shrinkage characteristics of the billet shell. And realize the rapid cooling of the corner of the slab; but the taper of the mold designed by this method needs to introduce a wedge-shaped structure at the corner of the wide-faced copper plate, which hinders the realization of the online width adjustment function of the mold, and is only applicable to the single-section slab continuous casting production;

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