SU1740124A1 - Method for continuous casting of cast pieces - Google Patents

Abstract

Use of the invention: metallurgists, continuous casting of billets from metals and alloys. SUMMARY OF THE INVENTION 1 Liquid metal from a tundish is fed through a nozzle into a mold. A solid shell of the preform is formed and pulled out of the crystallizer. Refrigerators are introduced into the liquid phase of the preform around the perimeter of the crystallizer before they come into contact with the inner surface of the hard shell of the preform at the exit of the crystallizer, 1 sludge.

Description

This invention relates to metallurgy, in particular to continuous casting.

The known method of continuous casting of metal, including the build-up of the crust of hardening metal in the mold on its internal walls due to the removal of heat through the walls.

The disadvantage of this method is the limited growth of the crust due to the formation of an air gap due to shrinkage of the metal, due to insufficient thermal conductivity of the material of the walls, the need to have an optimal casting speed of the heat.

The thickness of the crust of the hardened sheath of the steel ingot at the outlet of the mold is 15-30 mm at a drawing speed of 0.5-0.9 m / min. The drawing speed of the ingot is a function of the thickness of the crust. Insufficient thickness of the crust entails an increase in the number of breakouts and the formation of cracks on the surface of the ingot. The thickness of the shell of the ingot around the perimeter is uneven. This circumstance exacerbates the factors associated with insufficient thickness of the crust (shell) of the ingot, first of all the casting speed, which should decrease Casting of steel with low ingot drawing speed leads to an increase in metal casting capacity and machine capital intensity by 1 ton cast steel

The closest in technical essence to the present invention is a method for continuous casting of metal, including the introduction of powdered additives into the mold through the exothermic slag layer during the casting process.

The disadvantage of this method is that its performance is restrained by the thickness of the crust of the hardened shell of the steel ingot at the outlet of the crystallizer, since the addition of powdered additives to a small extent affects the cooling of the metal against the walls of the crystallizer.

In addition, during the passage through the slag layer, the powdery particles carry with them the slag inclusions into the ingot body, which reduces the quality of the workpiece.

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The purpose of the invention is to increase productivity by increasing the thickness of the shell of the extruded billet from the mold.

In order to achieve this goal, in a known method of continuous casting a billet, including feeding molten metal from an intermediate ladle through a casting cup into the mold, forming a hard shell of the billet and pulling it out of the crystallizer, introducing refrigerators into the liquid phase of the billet, entering the latter along the perimeter of the crystallizer to their contact with the inner surface of the hard shell of the workpiece at the exit of the mold.

The drawing shows a device for continuous casting blanks, designed to implement the method.

The device consists of a tundish 1 with an elongated pouring glass 2, introduced into the central part of the cavity, located under the bucket 1 of the mold 3,

The tundish 1 is provided with a stopper 4 and integrated mold 5 with heat-conducting sleeves 6 installed parallel to the contour of the casing 7 of the cast billet 8. The drawing also indicates: pos. 9 - liquid metal, pos. 10 - refrigerators.

The method is implemented as follows.

After the tundish 1 is filled with liquid metal 9, the opening of the steel pouring cup 2 is opened with a stopper 4 and part of the liquid metal 9 is directed to the mold 3. The crystallizers 3 and 5 are closed at this time with seeds (not shown). After the metal 9 is bonded with primers, they are pulled out of the molds 3 and 5. In this case, the coolers 10 are formed in the built-in molds 5, and the shell 7 of the workpiece 8 is formed in the mold 3.

The refrigerators 10, moving tangentially to the inner contour of the shell 7 of the blank 8 and having a temperature of 1100-1150 ° C. Which is lower than the melt temperature of the liquid metal, activate crystallization and fuse with the shell 7 of the blank 8, forming a thick crust. Further crystallization of the metal in the shell of the workpiece 8 is completed in the zone of the secondary

cooling.

Example. In conventional casting in a continuous casting plant, the metal is poured into a billet with a cross section, for example 400x1600 mm, at a speed of 0.4

m / min The mass of the smelting is 250 tons. A two-strand UNRS is required, on which the smelting will be spread in 60 minutes. When casting melting by the proposed method in the same billet section 400x1600 mm and

an ingot crust thickness of 70 mm, the casting speed is 0.8-1.0 m / min. The melting mass of 250 tons will be poured over the same 60 minutes, but not with a single-arm UNRS.

The active growth of the crust in the mold provides an increase in the speed of casting steel on UNRS and, accordingly, improves the performance of the method.

Claims (1)

Invention Formula Method for continuous casting of billets, which includes supplying liquid metal from the tundish through the nozzle to the mold, forming the hard shell of the billet and pulling it out of the crystallizer, introducing refrigerators into the liquid phase of the billet, characterized in that in order to increase productivity by increasing the shell thickness the preform being drawn out from the crystallizer; the inlets in the liquid phase of the preform are introduced into the liquid phase before they come into contact with the inner surface of the solid second envelope blank at the exit of the mold. BUT Aa