Method for determining heat transfer coefficient of secondary cooling zones in steel continuous casting process

Abstract

The invention relates to the field of ferrous metallurgy, in particular to a method for determining heat transfer coefficient of secondary cooling zones in a steel continuous casting process. The method is based on actually measured temperatures of outlets of all secondary cooling zones of casting steel grades and is simultaneously applicable to continuous casting of slabs and square billets. A computer is used as a continuous casting process server connected with an infrared thermal imaging instrument, the actually measured temperatures of the outlets of all the secondary cooling zones serve as the target temperatures, the heat transfer coefficient between casting blanks and cooling water is solved in iteration mode by aid of numerical simulation means so as to amend a heat transfer coefficient empirical formula and determine the heat transfer coefficient in different casting speed conditions. Blank casing thickness and the calculated value of temperature in an air cooling zone which are obtained in the method can be well matched with the actually measured values, namely the method can be effectively applied to the continuous casting process of casting machines of different types.

Description

technical field [0001] The invention relates to the field of iron and steel metallurgy, in particular to a method for determining the heat transfer coefficient of a secondary cooling zone in the steel continuous casting process. Background technique [0002] The essence of continuous casting of steel is the transformation process of molten steel into solid billet, accompanied by the release of superheat, latent heat and sensible heat. At the same time, solidification heat transfer in continuous casting controls solute diffusion and phase transformation, microstructure evolution, slab solidification shrinkage and distribution of thermal stress, and the position of solidification end. The heat transfer conditions in the secondary cooling zone of continuous casting are the key factors for formulating reasonable secondary cooling zones, the selection and arrangement of secondary cooling nozzles, and the distribution of water spray in the secondary cooling zone, and have a decisi...

AI Technical Summary

Problems solved by technology

However, in the actual continuous casting process, especially the slab continuous casting process, due to the shielding effect of the rollers in the secondary cooling zone, the infrared thermal imager cannot actually measure the temperature at each position on the surface of the slab

Chinese patent "CN1588023A" discloses a sensor that can directly measure the convective heat transfer coefficient and a method for measuring the convective heat transfer coefficient, but this method requires the sensor to be installed on the surface of the object to be measured, which greatly limits the use of this method in continuous casting Measurement of heat transfer coefficient in cold zone

At the same time, thermocouples and wires may not be able to withstand straightening stress and slab thermal stress, and directly adding thermocouples to the mold may affect the production rhythm and safety of continuous casting

Therefore, this method cannot be applied to the continuous casting production process

[0006] Chinese patent "CN201740750U" invented an experimental device for measuring the heat flow or heat transfer coefficient of thin strip continuous casting interface, which can effectively control the atmosphere in the furnace and truly simulate the production conditions of thin strip continuous casting, but it is not suitable for continuous casting of slabs

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