Control device and technology for corner cracks of microalloy steel sheet billet

Abstract

The invention provides a control device and technology for corner cracks of a microalloy steel sheet billet, and relates to the technical field of continuous casting and continuous rolling of steel sheet billets. The control device comprises a secondary cooling water distribution system, a corner efficient heat transfer narrow surface Gauss concave curved surface crystallizer and a crystallizer narrow surface foot roll zone new strengthened spraying system, wherein the new strengthened spraying system comprises a new water supply pipeline, a new strengthened spraying rack and a water distribution control system. In the control technology, dynamic water distribution is achieved through synergism of the corner efficient heat transfer narrow surface Gauss concave curved surface crystallizer,an integral strengthened cooling technology and a water distribution technology of the crystallizer narrow surface foot roll zone new strengthened spraying system and a wide surface integral slow cooling water distribution technology. According to the control device and the control technology, dispersion precipitation of microalloy carbonitride of corner structures of the cast billet can be stablyachieved, the corner structures of the cast billet are strengthened, narrow surface metals flow to side arcs during the large deformation pressing process of a liquid core of the cast billet, stressof the corner parts of the cast billet is reduced, and generation of the corner cracks of the microalloy steel sheet billet is radically controlled.

Description

technical field [0001] The invention relates to the technical field of continuous casting and rolling of steel thin slabs, in particular to equipment and technology for controlling cracks at corners of microalloy steel thin slabs. Background technique [0002] The thin slab continuous casting and rolling process was developed in the late 1980s and early 1990s. It is a new short-process strip steel production process, which is significantly different from the current traditional strip steel production process. It has significant energy saving and high product qualification rate. , Simplified production process, short production line, short product production cycle and other advantages, it has developed very rapidly in recent years. [0003] Thin slab production has a tight rhythm. If surface cracks occur during the slab production process, the subsequent continuous rolling products will have significant surface quality defects because the produced slab cannot be cleaned off t...

AI Technical Summary

Problems solved by technology

[0007] It can be seen from the above-mentioned currently published microalloy steel thin slab edge crack control method that it is mostly based on the principle of the third brittle temperature zone of steel, through the passivation crystallizer corner structure design or the development of the secondary cooling and weak cooling of the casting stream. Water distribution technology (including water conduction method) increases the temperature in the over-straightening area of ​​the slab corner to reduce the cracks at the slab corner, or reduces the microalloy and nitrogen content in the steel by controlling the molten steel composition and protecting the casting, thereby reducing The amount of precipitation of microalloy carbonitrides at the grain boundaries of the cast slab is not based on the fundamental mechanism of microalloy thin slab corner cracks, and the crack control effect in the actual implementation process is not very satisfactory.

At the same time, it is difficult to control the composition of molten steel or reduce the nitrogen and other components in steel by narrow composition, and it is difficult to control stably in the actual steelmaking process.

Therefore, at present, all thin slab production lines at home and abroad have failed to fully control the cracks in their microalloyed steel slabs

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