Production Method for Improving Microstructure Uniformity of Continuous Casting Billet

Abstract

The invention discloses a production method for improving the structure uniformity of a continuous casting square billet. d the molten steel smelted according to the preset components is subjected tocontinuous casting to form a continuous casting square billet. According to the production method, molten steel which is subjected to casting according to the preset components is made to form the continuous casting square blank billet after continuous casting; the continuous casting square billet passes through a secondary cooling area of the sector section of a continuous casting machine, the surface temperature of the continuous casting square billet is controlled to be cooled to 500-800 DEG C, the continuous casting square billet is made to sequentially pass through an electromagnetic induction coil assembly and a plurality of cooling sections for repeated temperature rise and cooling, so that the austenite is refined when the structures of the continuous casting square billet are repeatedly subjected to the austenite-ferrite-austenite phase change circulation, and the uniformity of the original as-cast structures is continuously improved.

Description

technical field [0001] The invention relates to the technical field of heat treatment of high-strength steel, in particular to a production method for improving the uniformity of the continuous casting billet structure. Background technique [0002] The low-magnification structure in the continuous casting billet consists of three crystal bands from the outside to the inside: fine equiaxed crystal bands (chilling layer), columnar crystal bands, and central equiaxed crystal zones (see figure 1 ). Due to the great difference in the shape and size of these three types of microstructures, the plasticity of steel slabs is poor for general steel products, and there are a large number of coarse columnar grains and equiaxed grains inside the as-cast microstructures, which are difficult to obtain in continuous casting. There are relatively fine equiaxed grains around the billet. During the subsequent austenitizing heating process, the size of the austenite formed inside and around t...

AI Technical Summary

Problems solved by technology

There are three main disadvantages in external heating: (1) The heating time is relatively long. For continuous heating furnaces, the heating time of continuous casting slabs is mostly more than 100 minutes, and the time for periodic heating furnaces such as pit furnaces and bell furnaces is several hours. , low production efficiency, and surface oxidation and decarburization

(2) The efficiency of the external heating furnace is low, the efficiency of the fuel furnace is lower than 40-50%, and the efficiency of the resistance furnace is about 70%

Moreover, the thermal inertia is large and requires a long start-up warm-up time

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