JPS58179541A - Method and device for continuous casting of metallic material having smooth surface - Google Patents

Abstract

PURPOSE:To cast a metallic material having no surface defect and has unidirectional solidified texture directly and continuously from liquid metal by maintaining the top end on the inside wall surface of a hollow mold at the solidifying temp. of the molten metal or above, immersing the bottom end of a dummy bar and taking up the dummy bar up. CONSTITUTION:A hollow heating mold 5 is provided in a holding furnace 1 for molten metal, and the top end of the inside wall surface of the mold 5 is held at the solidifying temp. of molten metal 3 or above by the heat of the metal 3. The bottom end of a dummy bar 6 is inserted and dipped into the molten metal 3 in the mold 5, and while the bar is taken up by the rotation of pinch rolls 9, the molten metal is cooled with a spray 7, whereby a metallic molding 10 is cast continuously. The solidification progresses always downward and the sound metallic material such as a pipe, wire, pipe or the like having no central segregation, shrinkage cavity or the like is formed directly from the molten metal by the above-mentioned method.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method and apparatus for directly manufacturing a metal material having a mirror surface, a unidirectional solidification structure, and any cross-sectional shape such as a rod, plate, or tube shape from a molten metal. Regarding.

More specifically, a mold or die for forming is immersed in the surface of the molten metal, a dummy bar of the metal molded body is inserted into the hollow part, and the temperature of the inner wall surface of the mold is adjusted to the solidification temperature of the molten metal to be solidified. While keeping the temperature above, pull up Damino (-), and at the upper exit of the hollow mold,
The present invention relates to a method and apparatus for continuously solidifying and manufacturing wire, rod, plate and tubular metal formed bodies.

Generally, wires, bales, plates, and tubes are made by plastic working from a lump of molten metal that is once solidified in a mold.

Generally, the surface of an ingot is not completely smooth, but has irregularities and often has cracks. Particularly in ingots obtained by continuous casting, surface defects such as surface patterns and cracks are likely to occur due to friction between the ingot and the mold as the ingot moves through the mold, and it is necessary to remove these surface defects. Therefore, the surface of the ingot is usually ground or scraped prior to plastic working such as forging or rolling.

Furthermore, when the cracks on the surface are deep, the ingot cannot be used for plastic working and becomes a defective product.

Therefore, it is extremely desirable to produce an ingot without surface defects from the standpoint of omitting the grinding process and improving the yield of the ingot.

In downward vertical continuous casting of metal ingots, the mold is usually required to slide downward F.

This is because if the solidified shell of the cast metal adheres to the inner wall of the casting I, when the ingot is pulled out from the mold, the solidified shell will break due to friction with the mold, so-called breakout.
This is because the unsolidified molten metal surrounded by the solidified shell will gush out.

Since such breakouts are particularly likely to occur in alloys with large solidification temperature ranges, such alloys, such as cast iron, should be completely solidified in the mold before being drawn out. After the subsequent molten metal has solidified (up to 2), it is drawn out again, with an intermittent 11'J.
"j, ii'i i leave 1') retail.

There has been a strong desire to develop a continuous casting method for alloys that are prone to such breakouts. Furthermore, the development of techniques for manufacturing wires, rods, plates, and tubes with mirror surfaces directly from molten metal has been awaited.

The present invention applies to all soluble metals and alloys.
It has a smooth surface with no surface defects and a unidirectional solidification structure.
The object is to provide a method for manufacturing wire, rod, plate and tubular metal materials directly from liquid metal.

In order to obtain a solid metal with a mirror-like or nearly mirror-like smooth surface, a hollow heating mold is used, and while the inner wall surface is heated, molten metal is continuously fed from above, little by little, until the molten metal flows inside the mold. This is possible in such a way that solidification occurs by cooling outside the outlet at the lower end of the mold without forming a solidification shell on the surface. However, in order to obtain a material with a mirror surface using this method, strict control is always required to keep the height of the molten metal in the mold low, and if the molten metal supply in the mold is too high, it will cause the mold to exit the mold. The molten metal ejects due to the pressure of the molten metal, making it impossible to obtain an ingot. In addition, if the cooling rate of the ingot is too fast, the molten metal will solidify easily in the mold, and due to friction with the mold, the surface of the ingot will be easily scratched and cracked. It is not possible to obtain mirror-finished ingots. In this way, creating mirror-finished ingots using this method requires extremely sophisticated level control technology.

The present invention can completely eliminate the risk of molten metal spewing out at the outlet of the mold, and can continuously produce a material having a mirror surface and having a structure that has grown in a long columnar shape in one direction. The present invention provides a method for manufacturing rod-shaped, plate-shaped, and tubular materials of all meltable metals and alloys by selecting an appropriate mold material.

A casting method without the risk of breakout is the upward continuous casting method, which is used in the production of rough drawn wire of oxygen-free copper. This is a water-cooled Daikoku S mold tn on the molten copper surface.
This is to pull up the rough line upwards. In this method, there is no risk of molten metal ejecting from the mold outlet due to molten metal pressure. However, since the black spear caster is water-cooled, the molten metal forms a solidified shell within the graphite mold.

Therefore, striped scratches are formed on the surface of the drawn wire due to friction with the inner wall surface of the graphite mold, making it impossible to obtain a mirror-finished material. Further, since solidification begins within the mold, crystals nucleated on the inner wall surface of the mold grow toward the center of the ingot against the heat flow, and cannot move through the unidirectional solidification structure.

The present invention provides an extremely useful method for continuously obtaining materials with a mirror surface and a unidirectional solidification structure with few internal defects without the risk of breakout at the exit of the mold. The purpose is to The present invention can be applied not only to pure metals, but also to the molding of alloys with a wide solidification temperature range, which have traditionally been considered extremely difficult to cast. This is because the mold is heated and the inner wall is kept above the solidification temperature of the molten metal, so the solidification of the molten metal progresses inside the mold avoiding the inner wall surface of the mold, and the inner wall surface of the mold should come in contact with it and rub against it. This is because there is no formation of a solidified shell.

That is, the present invention is a hollow mold immersed in the molten metal surface, that is, the temperature of the inner wall surface of the die is maintained at a temperature higher than the solidification temperature of the molten metal by the heat of the molten metal in contact with the die, thereby preventing the solidification shell on the inner wall of the mold. The molten metal that has been prevented from forming and reaches the upper end of the inner wall of the hollow mold due to the immersion of the mold flows out toward one end of the mold as the dummy bar inserted and immersed in the hollow part of the mold is pulled up. A continuous manufacturing method for wire, rod, plate, and tubular metal materials, characterized in that surface layer solidification is performed, and an apparatus used therein.

FIG. 1 is a longitudinal cross-sectional front view showing one embodiment of an apparatus for carrying out the present invention and manufacturing a rod-shaped material.

(It is a molten metal holding furnace and has a hot water supply chamber.■ is a molten metal and has a ■
Molten metal is supplied from the hot water supply pipe. (2) is a hollow heating type, in which the heat of the molten metal cools the inner wall of the hollow part at the exit of the mold, which is cooled by air, gas, mist, water, or other coolant ejected from the melt spray. ■ is a shield plate that protects the mold from being cooled. By controlling the hot water level in the hot water supply chamber (2), the molten metal in the mold (2) must be kept constant so that it does not overflow from the mold. Metal molded bodies 0 can be continuously cast by moving the metal molded body dummy gun (①) set in the mold (②) upward by the rotation of the pinch rolls (②).

In carrying out the present invention, it is important to appropriately select the temperature of the molten metal in the molten metal holding furnace and the material α of the mold so that the temperature of the upper end of the inner wall of the hollow mold is maintained above the solidification temperature of the molten metal. There must be. For alloys with low solidification quality, such as aluminum alloys and copper alloys, graphite, silicon carbide, and Noricon nitride types can be used. In addition, steel, cast iron, and alloys with high melting points include alumina,
/ Rika, Berylia, Magnenoa, Torya, Zirconia,
Refractory materials mainly composed of gelonite 1ride, silicon carbide, etc. can be used, but when selecting them, it is necessary to select a material that reacts with molten metal, does not corrode, and is thermally conductive and easily eroded. In addition, the lower end of the dummy bar needs to have a constriction so that the cast metal molded body can be raised in close contact with the dummy bar.

The method developed in this study is particularly superior to the conventional continuous casting method for ingots because it can produce a material with a mirror-like or near-smooth surface without the risk of surface cracks, and it also prevents breakouts. The danger is that metals and alloys with a unidirectional solidification structure can be manufactured continuously into wires, rods, plates and tubes with cross-sectional shapes, without any danger.

According to the method of the invention, solidification always proceeds downwards because there is no cooling from the side walls of the mold. Therefore, (te
In particular, Azuma's method makes it possible to easily obtain a material that is free from center segregation and shrinkage cavities due to the growth of crystals from the casting wall surface to the center of the ingot.

+The invention is not only extremely useful for improving the surface condition of ingots, but also solves the problems that have been required in conventional methods.
The equipment and energy required for the +4q sliding movement become scarce, and the addition of glassy surface additives for lubrication of the Z mold and ingot used in continuous steel casting becomes almost indispensable. In addition, it has the advantage of being able to directly form plates, wires, and tubes from molten metal, which conventionally required forming from an ingot by repeating plastic working and longevity treatment, which saves energy and labor. This is also an innovative manufacturing method for metal materials. Furthermore, since it is possible to obtain an infinitely elongated columnar structure, materials such as magnetic steel, where a unidirectional solidification structure is desired, have traditionally been cast one by one in a mold by setting the alloy. It can also be used by forming a long rod-shaped unidirectionally solidified material and then cutting it into the required length. A particularly good feature is that since there are no equiaxed crystals, there is no formation of microscopic defects in the grain boundaries due to the precipitation and accumulation of equiaxed crystals in the compact, resulting in an extremely healthy product. The present invention is an innovative method for manufacturing metal materials in that a scrap material molded body can be obtained by simple solidification.

-4. Brief description of the drawings Fig. 1 is a vertical cross-sectional front view of the main part showing one embodiment for implementing the present invention and producing a rod-shaped metal molded body. Temperature furnace ■ Metal molded body dummy bar ■ Supply Tin chamber - Spray coolant (4) Molten metal
■Shielding plate (4) Hot water/pipe ■Pinch roll (reheating type [phase] Metal molded body patent applicant +111

Claims (1)

[Scope of Claims] 1. Insert the lower end of the metal molded object (ingot) dummy bar into the hollow mold with the molten metal intermediate stand, and pull it up while keeping the upper end of the inner wall surface of the hollow mold at a temperature higher than the solidification temperature of the molten metal by the heat of the molten metal. An upward continuous casting method for metal molded bodies. 2. A dummy bar for large-scale upward continuous casting of a metal molded body, which has a constriction at the lower end with a cross section smaller than the horizontal cross section of the ingot. 3 Metal forming characterized by inserting the lower end of a metal molded object (ingot) dummy bar into the molten metal in a hollow mold, and pulling it up while keeping the upper end of the inner wall surface of the hollow mold above the solidification temperature of the molten metal by the heat of the molten metal. Upward continuous casting equipment for bodies