SU1006048A1 - Top to ingot mould for casting ingots with closed shrink hole - Google Patents

Description

The invention relates to ferrous metaplurgia and can be used in casting steel into molds with extensions for casting ingot with shrinkage sink. A well-known extension for a mold when casting ingots with an open shrinkage shell, concentrated in the upper part of the ingot, contains a metal case with a bored central hole, lined inside by an insulating material f 1J. However, the use of such an extension cannot provide an ingot with a closed shrinkage shell. Closest to the present invention is an extension to a mold for casting steel ingots with a closed shrinkage shell, comprising a housing with a through central hole lined in the upper part with an insulating material and a massive lower part without lining. The extension body is provided with centering legs and tides for gripping during lifting. The extension provides an ingot with a closed shrinkage shell when casting quieter L2 steel. However, this results in a relatively high head trim from the ingot during rolling, which reduces the yield of good steel. In addition, to ensure that the closed shrink shell is isolated from the atmosphere, the rate is high and narrow, which makes it difficult to lining and lubricating before casting. Other dimensions of the extension do not provide isolation of the closed shell without a significant increase in the capacity of the upper part of the extension, which increases the head edge. The aim of the invention is to increase the yield of steel from the ingot. The goal is achieved by the fact that in an extension to a mold for casting ingots with a closed shrinkage shell, comprising a housing with centering legs and tacks during lifting, the housing is detachable and in the lower inner part has a narrowing formed by protrusions located on two opposite walls the hull, while the minimized value of the restriction is selected from the following relationship: i.e. ° ph where O is the minimum value of the restriction (the distance between the projections), Mj. ot is the coefficient of intensity of hardening of steel in the lower part of the extension (in pinching) compared to the upper; V is the volume of the upper part of the body of the extension to the projections, m; p is the inner perimeter of the upper part of the extension at half its height, m, h is the height of the body of the extension from the upper edge to the protrusions, m. In this case, the projections in the vertical section have the shape of a segment. In addition, the projections in the vertical section have the shape of a trapezoid with inclined lateral sides. The extension body above the protrusions may be partially or fully lined. The extension can be made with any form of internal horizontal speech. IF, due to the presence of protrusions in the lower part of the body of the extension, which form a narrowing, the possibility of heat dissipation increases even more in comparison with the known extensions, since the relative BepxHocfTb heat sink increases. Therefore, during solidification of the ingot, a bridge of solid metal quickly appears here. Above the bridge, the ingot shrinkage shell is open, under the closed bridge. The walls of the closed shell are welded during rolling, the walls of the open shell are not welded and retracted. The metal from the top of the extension is consumed during hardening to compensate for shrinkage and build-up. It is known that in order to compensate for shrinkage of the ingot, which does not exceed 4-5% of the ingot volume, 16-20% of metal is poured into profit, i.e. Each amount of metal spent on the compensation of ingot ingot is 4-5 volumes of metal per nastily. Therefore, the more intense the hardening of steel in the lower part of the extension, the earlier the pinch will be obtained, the less the metal will be consumed from the profit on compensation for shrinkage and formation of walling. In this connection, the possibility of reducing profit margins and, consequently, the head trim of an ingot is created. But if liquid metal is consumed from the top, the extensions before the solid metal bridge forms at the bottom of the extension, then the entire shrinkage shell will be open. The walls of such a shell are not welded during rolling and the trimming of the ingot increases to 30-40% by weight. In order to avoid this phenomenon, as studies have shown, it is necessary to observe the following correlation between the dimensions of the constriction and the extension-D: 3. ph where D is the constriction size, m / oi. The coefficient of hardening of steel in the lower part of the extension (in compression) compared to the upper, V, p, h, is the design parameters of the extension of the extension. Coefficient . o “1. shows the thickness of the layer of hardened steel on the upper part of the extension in the case of lining with refractory material i In the absence of the lining, about 1, when lining the walls of the upper part of the extension (above the protrusions) with chamotte ci 2, when using a printed lining of sand o6 2 and etc. Fig. 1 shows the proposed extension, a section; Fig. 2 is also a top view; Fig. 3 is an extension at the time of removal from the ingot; Fig. 4 is a profitable part of an ingot obtained using the proposed extension, a slit .. The extension contains a body, In the lower part of the body, protrusions 4 are located on two opposite walls, which form a constriction. For transporting the extension by crane, it has a tide of 15 pins 6 and brackets 7. To center the extension to set out The extension body has paws 8. The half of the extension body is connected with the help of rods 9 and wedges 10. The rod 9 is fixed at one end to one of the half of the extension body. The second half of the extension body has a through hole for the second end of the rod. The bar goes through the hole and protrudes with the free end of the extension body. The speaker - the end of the rod has a hole for the wedge 10. To connect the halves of the extension, the housing is raised by the trunnion 6. In this case, the half of the body spontaneously closes, after which the wedge 10 is hammered into the hole of the rod 9. The assembled extension is transferred onto the mold with a crane. paws 8. The extension is ready to receive metal. To remove the extension from the ingot, they knock out the wedge 10 from the rods 9 and with the tap for the tides 5 lift the extension up. In this case, the half of the extension is opened at an angle sufficient to cover the wide part of the ingot's profit (Fig. 3). The extension removed from the ingot in the open position is installed on a rack where the extension is prepared for operation. . The proposed extension design reduces the ingot trimming by about 4-6% and thus increases the yield of steel from the ingot. In addition, it greatly facilitates the maintenance of the extension not only in the absence of a lining but also in the presence of it, since the dimensions of the lined part are small and more accessible to work. The expected economic effect is 2-10 rubles per ton of steel depending on the grade.

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Claims (3)

1. SUPPORT TO THE ESTIMATE FOR CRIMPING INGOTS WITH A CLOSED SHRINKING SHELL, comprising a body with centering paws and tides for gripping when lifting, characterized in that, in order to increase the yield, the body is made detachable and in the lower inner part has a constriction formed by protrusions located on two opposite walls of the body CA, while the minimum contraction is selected from the following relation: * 0 <, ph ’where D is the size of the narrowing (the distance between the protrusions), m) d is the coefficient of intensity of solidification of steel in the lower part of the extension (in pinch) compared to the upper one) V is the volume of the upper part of the extension casing to the projections, m ^) p is the inner perimeter of the upper part of the extension casing at half its height, m, 'h is the height of the extension casing from the upper edge to the protrusions, m. 2. Extension on π. 1, characterized in that the protrusions in a vertical section have the shape of a segment. '' 3. Extension by π. 1, characterized in that the protrusions in a vertical section have the shape of a trapezoid with inclined sides.