JPS60137551A - Method and mold for horizontal and continuous casting - Google Patents

Abstract

PURPOSE:To obtain a casting ingot having internally no inclusion, segregation, etc. by constituting the lower part of a casting mold of a material having high heat conductivity, constituting the upper part of the mold of a material having low heat conductivity and solidifying a molten metal from the lower part toward the upper part. CONSTITUTION:Lower materials 11, 14 of a casting mold are formed of a material such as copper alloy, etc. having high heat conductivity and upper materials 9, 15 are formed of a material having low heat conductivity which is oxide ceramics or sulfide ceramics such as Cr2O3, Al2O3 or the mixture composed thereof. The materials 11, 14 are cooled by cooling water 10 and the materials 9, 15 are heated if necessary. The molten metal 8 in a holding furnace 7 for the molten metal begins to solidify from the lower part in the casting mold and the solidification progresses gradually toward the upper part. Since the segregation, etc. generated in the stage of solidification move toward the upper part, inclusion, segregation, etc. are not generated in the casting ingot.

Description

[Detailed description of the invention] The present invention relates to a horizontal continuous casting method for ingots.

Horizontal continuous casting with tp'i 9, which involves solidifying the molten metal in the mold from the bottom to the top to cast a healthy ingot with no macroporosity, inclusions, or segregation in the axial center of the ingot. Regarding the Act and Type 15 therefor.

Conventionally, in the horizontal continuous casting method, molten metal is supplied from one end of the mold to a cooling mold made of graphite or copper with good thermal conductivity and has nine central holes, and the molten metal is poured from the outside of the cross-section of the molten metal into the axial center of the mold. This is a method in which the ingot is solidified toward the end of the ingot, and the ingot is pulled out horizontally from the other end.This method is widely used in the production of ferrous and non-ferrous alloys because it allows for downsizing of equipment. In this method, the supplied molten metal is rapidly cooled in the mold, a solidified shell is formed from the periphery in contact with the cooling mold, solidification gradually progresses toward the center, and finally the center solidify.

In the conventional horizontal continuous casting method as described above, solidification starts from the periphery of the molten metal in the mold and gradually progresses inward, so gases or inclusions generated during solidification are concentrated in the center of the ingot. Furthermore, since component segregation is significant, defects are likely to occur in the center of the ingot.

The present invention has devised a casting method and a mold for the purpose to prevent such defects from occurring inside the ingot, and the molten metal in the mold is solidified from the bottom to the top. The present invention relates to a horizontal continuous casting method characterized by a horizontal continuous casting method and a mold for horizontal continuous casting that is composed of a lower member made of a material with high thermal conductivity and a ten-piece wing made of a material with low thermal conductivity.

By using the mold of the present invention as described above, the molten metal in the mold starts solidifying from the bottom.

As casting progresses, it gradually solidifies in the direction of the soil. Therefore, gases, inclusions, segregated substances, etc. generated during solidification rise along with the solidification interface, and eventually come out of the ingot, resulting in an ingot without casting defects such as segregation inside the ingot. Furthermore, if the above-mentioned impurities are concentrated in the upper part of the ingot, they can be simply removed by grinding only the upper part of the ingot, if necessary, making processing easier.

The material with high thermal conductivity for the lower part of the mold used in the present invention is conventionally used mold materials such as (g) alloy, copper alloy plated with chromium, etc., or molten metal such as graphite. Any material that can be solidified by water cooling may be used. One material with low thermal conductivity for the upper part of the mold used in the present invention is Cr103 # A120B + Pb
Oxide ceramics such as O* Oak, MgO, Eli02+ 5b203°Zr01, 'Mob,, W
Any material having excellent heat resistance such as sulfide ceramics such as FI, nitride ceramics such as BN, or a mixture thereof may be used.

It is also possible to line these ceramics to form the upper part of the mold.

In contrast to the lower mold member, which is cooled by the selection of the mold material in the present invention, the temperature of the other upper mold member has a gradient in which the temperature decreases from the molten metal supply side toward the ingot drawing outlet. The top of the mold can also be heated to increase the temperature.

Furthermore, when using a mold with an open top, a material with high thermal conductivity may be used for the lower mold, and the open top surface may be heated and kept warm by full resistance heating, gas heating, or the like.

Furthermore, if a weir is provided above the molten metal in such an open-top mold, the impurities that floated up as described above can be removed by the weir, making it possible to obtain a cast product with few defects in the upper part of the ingot. When using the present invention, the cross-sectional shape of the mold is not particularly limited, and the horizontal continuous casting of the present invention is applied to the production of ingots with a cross-sectional shape of 1 circular cross-section, 7t'1. can. 2 Next, the present invention will be explained with reference to the drawings.

Figure 1 shows the conventional horizontal continuous casting method, in which molten metal 2 in a holding furnace or tundish 1 passes through a mold 4 cooled by a cooling medium 6 such as water, and solidifies. The mass 5 is continuously pulled out from the outlet end of the mold by pinch rolls 6.

As shown in FIG. 1, the molten metal in the mold starts solidifying from the periphery where it contacts the mold 4, and gradually solidifies toward the center. Therefore, gas generated during solidification, impurities, etc. cannot escape completely, resulting in an o11 shrinkage defect in the center.

In contrast, in the present invention, as shown in FIG. 2, the lower member 11 of the mold is cooled with cooling water 10.

By using a refractory material with low thermal conductivity for the upper member 9 of the mold, the molten metal 8 in the molten metal holding furnace 7 starts solidifying from the lower part of the mold and gradually progresses to the upper part.

It can be seen that the solidification interface with the ingot becomes a field T i Fi as shown in FIG. 2, and that the gas or segregation generated during solidification moves to the upper part of the ingot.

The solidified ingot 12 is pulled out by pinch rolls 16 as in FIG. 1.

The horizontal continuous casting method of the present invention, in which only the lower part of the mold is cooled and the molten metal solidifies from the lower part to the upper part, is an innovative method that does not generate macroporosity, inclusions, or segregation in the center. .

FIGS. 3(a), (0), and (c) show examples of molds of the present invention.

These molds are all molds for obtaining an ingot with a rectangular cross section, but the present invention can also be applied to molds with a round cross section or a cross section of a different shape.

Figures 6(a) and 6(b) show cross sections of a closed type horizontal continuous casting mold. The upper mold member 15.17 is made of a refractory material with low thermal conductivity, and the lower mold member 14.15 is made of a material with high thermal conductivity. The lower part 14.15 of the mold is then cooled, and the upper part 15.17 of the mold is heated as required. FIG. The side wall 19 is made of a material with low thermal conductivity. In this mold, to slow down the solidification of the upper part of the molten metal.

The upper part of the mold can also be maintained at a high temperature by resistance heating, gas heating, or the like.

[Brief explanation of the drawing]

Fig. 1 is a schematic explanatory diagram of the conventional horizontal continuous casting method, Fig. 2 is a schematic explanatory diagram of the horizontal continuous casting method of the present invention, and Figs. 3 (a), (b), and (c) are FIG. 3 is a sectional view of a horizontal continuous casting mold. 1.7; Molten metal holding furnace or tundish 2.8;
Molten metal 4; water-cooled mold s, 1o: cooling medium s, 12; ingots 6, 13; pinch rollers 15, 17, 1q: mold upper member 14 with low thermal conductivity;
16.1a; Mold lower member box with high thermal conductivity I L<
1';i> 2 1 ・i 2'! '; 3 " (a) 4 (c) t'<i (b)

Claims (2)

[Claims] (1) A horizontal continuous casting method characterized by solidifying the molten metal in the mold from the bottom to the top. (2) A horizontal continuous casting mold for solidifying molten metal from the bottom to the top, consisting of a lower member made of a material with high thermal conductivity and an upper member made of a material with low thermal conductivity.