RU2342220C2 - Cooling technique of ingot-forming equipment - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: ingot-forming equipment is cooled down by cooler, fed from side of melt receiving through top collector into annular gap between casing and screen and withdrawn trough offtake collector. On casing cooler is fed as sink streams through holes or grooving, implemented in screen. There are implemented holes or grooving at an angle of 90°±45° to surface of cooling and for a depth, not less than 0.2 of ingot-forming equipment casing length.

EFFECT: productivity improvement of casting process and improving of blank.

2 cl, 1 dwg, 2 ex

Description

The invention relates to metallurgy and is intended for casting billets and ingots of metals and alloys in metal water-cooled forms.

A known method of cooling the mold (Bevza VF and others. Continuous casting by freezing. Mn .: Science and technology, 1979, p. 184, Fig. 84) [1]. In this method, the cooler is supplied to the lower supply collector, in the form of a radial flooded jet, which cools the mold jacket, then moves in the annular gap between the screen and the jacket into the outlet manifold. In this method, only a very small part of the shirt is cooled most intensively, equal to the height of the annular gap, and only if this value is comparable to the width of the annular gap between the screen and the mold jacket.

A known method of cooling the mold (Baranov OA and others. Continuous casting of cast iron. M: Metallurgy, 1968, p. 278, Fig. 102) [2]. The method includes supplying a cooler to the lower supply manifold, cooling the mold shirt by flooded jets from the openings in the screen and subsequent movement of the cooler in the annular channel between the jacket and the screen into the discharge manifold. The disadvantage of this method is that the lower part of the mold shirt is most intensively cooled at a height of 0.10-0.15 of its length, while the main heat transfer intensity occurs in the upper part of the mold jacket, from the liquid metal supply side. This leads to a decrease in the productivity of the casting process and a deterioration in the quality of the workpiece.

The closest technical solution to the proposed one (prototype) is “Crystallizer for continuous casting of ingots” (patent No. 1959 U, BY, publ. 2005.06.30, class IPC B22D 11/00) [3], which implements a method for cooling the mold. The method includes supplying a cooler to the upper supply manifold from the side of the melt supply, uniform along the perimeter of the crystallizer jacket, cooling it with flooded jets from the openings in the screen, and subsequent movement of the cooler in the annular channel between the jacket and the screen into the discharge manifold. This method does not indicate such important cooling parameters as the depth of cooling of the jacket, the angle of cooling by the jets of the cooler and their shape, on which the cooling ability of the mold, the productivity of the casting process and the quality of the workpieces substantially depend.

The technical problem to which the claimed method of cooling the mold is directed is to increase the productivity of the casting process and improve the quality of the workpiece. The problem is achieved in that in the claimed method, which includes supplying a cooler to the upper supply collector from the side of the melt supply, uniformly cooling the flooded jets from the openings in the screen along the perimeter of the mold jacket and the subsequent movement of the cooler in the annular channel between the jacket and the screen into the outlet manifold, cooling of the shirt is carried out by flooded jets at angles of 90 ± 45 ° to the cooling surface to a depth of at least 0.2 of the length of the mold shirt.

Flooded cooling jets can be formed with holes in the form of vertical through grooves in the screen.

The drawing shows a diagram of the jet cooling of the mold during continuous casting of ingots of metals and alloys, where 1 is the supply collector, 2 is the casing, 3 is the screen, 4 is the mold shirt, 5 is the discharge collector, 6 is the melt, 7 is the ingot.

The cooling of the mold is as follows. The cooler is fed into the upper supply manifold 1 between the casing 2 and the screen 3. Then, through the openings in the screen, the flooded jets of the cooler strike uniformly around the perimeter of the outer surface of the shirt 4. Reflecting from it, the flow of coolant moves in the annular gap between the jacket and the screen into the outlet manifold 5. For more uniform cooling height of the mold, the cooler jets can partially or completely strike at angles of 90 ± 45 ° to the cooling surface.

When jet cooling the mold to a depth of h (see drawing) less than 0.2 of the length of the shirt, there is a significant decrease in the productivity of the casting process due to the absence of gas shrinkage between the ingot 7 and the mold jacket 4 (see drawing).

When cooling the mold jacket by flooded jets at angles less than 45 ° and more than 135 ° to the cooling surface, the mold cooling capacity is significantly reduced due to a significant increase in the thickness of the thermal boundary layer between the outer surface of the mold jacket and the flow of cooler.

Example 1

Continuous casting into a crystallized jet cooler obtained an O3TS7S5N bronze ingot with a diameter of 50 mm. The mold jacket was cooled by jets of water at angles of 45 °, 90 °, 135 ° to the cooling surface, while the depth of cooling of the jacket was 0.5 of its length. At an inlet pressure of 2 atm and a water flow rate of 50 m ³ / h, in comparison with a conventional (slit) crystallizer, ceteris paribus, the jet allowed to increase the productivity of the casting process by 2 times and grind the microstructure of the ingot 3-5 times.

Example 2

By casting into a mold with jet cooling, billets of silumins AK12 and AK18 with a diameter of 50 mm and a height of 200 mm were obtained. The mold jacket was cooled by jets of water at an angle of 90 ° to the cooling surface, while the depth of cooling of the jacket was 0.9 of its length. At an inlet pressure of 4 atm and a water flow rate of 50 m ³ / h, in the absence of modifiers, it was possible to disperse primary silicon crystals in the castings up to 20-30 μm, and eutectic crystals up to 1-2 μm.

Information sources

1. Bevza V.F. and others. Continuous casting by freezing. Mn .: Science and technology, 1979, p. 184, Fig. 84.

2. Baranov O.A. and others. Continuous casting of cast iron. M .: Metallurgy, 1968, p. 278, Fig. 102.

3. Utility Model Patent No. 1959U, BY 2005.06.30, cl. IPC B22D 11/00.

Claims (2)

1. The method of cooling the mold, including the supply of a cooler to the upper supply manifold from the melt supply side, uniform cooling of the mold jacket along its perimeter by flooded jets from the openings in the screen and the subsequent movement of the cooler in the annular channel between the jacket and the screen into the exhaust manifold, characterized in that the mold is cooled to a depth of at least 0.2 of the length of its shirt with flooded jets at angles of 90 ± 45 ° to the cooling surface. 2. The method according to claim 1, characterized in that the holes in the screen are made in the form of vertical grooves.