SU1103937A1 - Method of cooling continuously cast ingot - Google Patents

Abstract

COOLING METHOD OF CONTINUOUSLY INTEGRATED INGOT, including a uniform supply of water along the perimeter of the cross section water is fed with a change in speed V in the direction of ingot movement according to V A- {AB | U / tr, where A is 0.15-0.3 m / s, the flow rate of water at the beginning of the cooling zone, B is 0, 8-1.3 m / s, water flow rate at the end of the cooling zone, "Z - distance from the beginning of the cooling zone in the direction of movement of the ingot i, M} L - cooling zone length, m; (L h - 1-3, coefficient of change of speed of a channel of water. With

Description

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FIELD OF THE INVENTION The invention relates to metallurgical industry, namely to continuous casting. steel, and can be used to produce a fine-grained casting of round or rectangular cross section. There is a known method for cooling a continuously cast ingot, which includes cooling the ingot leaving the mold evenly around the perimeter of its cross section with flowing water flowing in the direction of; opposite to the ingot movement. This method dramatically increases the cooling rate and virtually eliminates chemical heterogeneity across the ingot section. However, due to the intense heat removal and the resulting high thermal stresses, cracks are formed in the ingot that are not welded during rolling. Closest to the invention of the technical essence and the achieved result. is a method of cooling a continuous cast ingot, including a uniform supply of water along the perimeter of the ingot’s cross section in the direction opposite to its Motion, a flow rate of 1.3-1.7 l / kg metal 2. A disadvantage of the known method is the increased cracking in the ingot due to the unregulated intensity of the cooling of the ingot surface in the direction of its drawing is not due to the fact that the water supply is carried out with. constant flow rate. The purpose of the invention is to reduce thermal stresses and improve the quality of ingots. The goal is achieved by the fact that according to the method of cooling a continuously cast ingot, which includes a uniform supply of water along the perimeter of the ingot cross section in the direction opposite to its movement, with a flow rate of 1.3-1.7 liters / kg of metal, water is supplied with a change in velocity V in the direction of ingot movement depending on the v / -H-8Kz / L bridge); where A is 0.15-0.3 m / s, the velocity is about the flow of water at the beginning of the cooling zone; B — 0.8–1.3 m / s, water flow rate at the end of the cooling zone; Z is the distance from the beginning of the cooling zone in the direction of ingot movement, m-, L is the length of the cooling zone, m; f - 1-3, the rate of change of the flow rate of water. At a flow rate of 0.15 m / s and B 0.8 m / s, there is a danger of breakthrough of the ingot crust at its exit from the mold due to the low intensity of the ingot cooling, at A70.3 m / s and B 1.3 m / s the formation of surface cracks due to high thermal stresses. The length of the cooling zone L is 0.2-0.4 the depth of the liquid well of the hardening ingot. At L 0, the depth of the well there is a danger that the liquid core of the ingot goes beyond the cooling zone of length L 0.4 of the depth of the well. to the growth of thermal stresses and the formation of cracks, the range of changes in n 1-3 provides the necessary smooth increase in the flow rate at the beginning of the cooling zone and the necessary degree of growth at the end of the cooling zone. Example. The U13A steel is poured into an ingot with a section of 82-82 m with the following parameters of the cooling process: water consumption — 1.3 l / kg metal, A 0.3 m / s, B 1.3 m / s, L 800 mm, n 1, 5, the ingot surface temperature at the exit from the cooling zone is 1100 ° C. The results of the analysis of the quality of the macrostructure of an unregularly ingot are given in the table. I As follows from a comparison of cooling results with constant and variable water flow rates, cooling with a variable flow rate can significantly reduce cracking in the ingot due to a decrease in its thermal stresses. The use of the proposed method allows to obtain a small section and round or rectangular billet with a diameter or thickness of up to 100 mm with minimal chemical heterogeneity and a satisfactory macrostructure and, thus, improve the quality of ingots and yield of the cast billet.

With constant flow rate, 1.3 m / s

Variable flow rate from 0.3 m / s to 1.3 m / s

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Claims (1)

METHOD FOR COOLING A CONTINUOUS INGOT, including a uniform water supply along the perimeter of the cross-section of the ingot in the direction opposite to its movement, a flow rate of 1.3-1.7 l / kg of metal, characterized in that, in order to reduce thermal stresses and improve the quality of the ingots, water is supplied with a change in the velocity V in the direction of movement of the ingot according to the dependence V = A- (A-B | (Z / L |, where A is 0.15-0.3 m / s, the flow rate of water at the beginning of the cooling zone; B - 0.8-1.3 m / s, water flow velocity at the end of the cooling zone; Z is the distance from the beginning of the cooling zone in the direction of movement of the ingot, m; L is the length of the cooling zone, m; η - 1-3, coefficient of change ’water flow rate. SU „, 1103937 1 1103937 1