Method for determining heat flux density of continuous casting crystallizer based on flux film and air gap dynamic distribution

Abstract

The invention belongs to the field of metallurgy continuous casting process numerical analog simulation, and discloses a method for determining heat flux density of a continuous casting crystallizer based on flux film and air gap dynamic distribution. According to a crystallizer copper plate structure and the size of the section of a continuous casting, a two-dimensional transient heat/force coupling finite element model with a 1/4 blank shell-crystallizer cross section system as a computation object is built, and the temperature of the surface of the blank shell, the temperature of the hot surface of a copper plate and the width of the clearance of a blank shell-crystallizer interface are determined. If the temperature of the surface of the blank shell is higher than the solidification temperature of casting powder, the heat resistor of the blank shell-crystallizer interface is formed by connecting a melt cinder layer, a solidification slug layer and a crystallizer-solidification slug interface heat resistor in series. If the temperature of the surface of the blank shell is smaller than or equal to the solidification temperature of the casting powder, the heat resistor of the blank shell-crystallizer interface is formed by connecting an air gap layer, a solidification slug layer and a crystallizer-solidification slug interface heat resistor in series. The method has good universality, and is suitable for determining the heat flux density of all existing continuous casting machine types and sectional crystallizers.

Description

technical field [0001] The invention relates to a method for determining the heat flux density of a continuous casting crystallizer based on the dynamic distribution of slag film and air gap, which belongs to the field of numerical simulation of metallurgical continuous casting process. Background technique [0002] As a high-efficiency heat transfer device, the crystallizer undertakes the task of initial solidification of high-temperature molten steel to form billets, and its heat transfer uniformity directly determines the surface quality of continuous casting billets. For this reason, studying the heat transfer behavior of crystallizers has become an important focus in recent years. However, in actual steel continuous casting production, the mold has the characteristics of high temperature and "black box", so it is very difficult to directly detect or measure the heat transfer behavior in the mold. In recent years, with the development of numerical simulation technology ...

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Problems solved by technology

But this method has the following disadvantages: (1) the premise of this method to determine the heat flux density is to provide the billet shell surface temperature in the mold, but in the actual continuous casting process, the billet shell surface temperature in the mold is difficult to measure, so it is not necessary (2) The mold powder thickness determined by this method does not consider the dynamic shrinkage behavior of the billet shell in the mold, which is inconsistent with the actual continuous casting process; (3) The heat flux determined by this method is only along the mold Longitudinal variation, unable to determine the heat flux distribution in the peripheral direction of the mold

However, this method also has the following disadvantages: (1) When calculating the thickness of liquid / solid mold flux in this method, the slab shell surface temperature provided by the built-in online simulation system of the continuous casting machine must be taken as the premise, but in the actual continuous casting process, if The continuous casting machine simulation system can accurately give the surface temperature distribution of the slab shell, and the heat flux of the mold can be directly determined, so it is not meaningful to determine the heat flux of the mold by this method; (2) the prerequisite data required by this method The slag path profile curve of No. 1 also does not consider the dynamic shrinkage of specific steel types in the mold, and the thickness of liquid / solid mold flux obtained from it cannot accurately describe the actual process of continuous casting; (3) The value determined by this method The heat flux of the mold also only considers the change along the height direction, but cannot determine its distribution in the circumferential direction of the mold

This calculation method also has the following disadvantages: (1) The heat flux determined by this method is the average heat flux in the entire crystallizer, which cannot reflect the local heat flux characteristics of the crystallizer; (2) when calculating the instantaneous heat flux in the crystallizer, Classical heat flow calculation formula obtained, but this heat flow calculation formula is only applicable to static water-cooled crystallizers, not fully applicable to the determination of the heat flux density of steel continuous casting molds with actual circulation cooling

This method also has the following disadvantages: (1) The implementation of this method needs to be based on a special mold thermocouple embedding method, but the structure of the mold copper plate in actual continuous casting production is certain, and the embedding of thermocouples according to this method is realized. Very difficult; (2) It is impossible to give the local heat flow in the corner of the crystallizer and other areas

However, in actual production, due to the influence of shell-mold interface gap and shell temperature changes, mold flux and air gaps are dynamically filled in the interface, making it very difficult to accurately describe the interface heat transfer behavior

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