JPS58157552A - Continuous casting method of metallic material - Google Patents

Abstract

PURPOSE:To prevent the damage of a casting mold by friction with a continuous casting ingot and to enable the production of the continuous casting ingot having smooth surfaces by forming a hollow casting mold for continuous casting so as to have the inside wall surfaces having gradients diverging toward the outlet for the ingot and to maintain molten metal at the solidifying temp. thereof or above. CONSTITUTION:A casting mold 3 for continuous casting of which the inside wall surfaces have upward diverging gradients is put in a holding furnace 1 contg. the melt 2 of the metal to be cast, and the top end in the hollow part of the mold 3 is held to be below the surface of the melt 2 to prevent the intrusion of the melt 2 at the edge 4. A dummy 6 for continuous casting is put into the mold 3, and is touched and stuck to the melt 2, then the dummy is taken up with pinch rolls 9, whereby a continuous casting ingot 10 is produced. The ingot 10 forms a solidified shell in the outlet of the mold 3, and since the casting hole of the mold 3 forms the upward divergent gradients, the ingot 10 does not stick to or rub with the inside walls of the mold 3, whereby the continuous casting ingot having smooth surfaces without breakout is produced without damaging the mold 3.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method of supplying the molten metal from one end and casting from the other end, in order to directly produce a metal material having an arbitrary cross-sectional shape such as a rod shape, a plate shape, or a tubular shape from a molten metal. An inner wall of a mold for carrying out a continuous casting method for metal ingots, characterized in that the temperature of the inner wall surface of the outlet of the mold is maintained at a temperature higher than the solidification temperature of the cast metal for continuously obtaining ingots. This invention relates to a continuous casting method and device that are effective in preventing breakage.

More specifically, on the inner wall surface of a hollow mold for continuous casting, which is heated by the heat of the molten metal or the heat of a heating element built into the mold,
The present invention relates to a method and an apparatus for continuously manufacturing metal molded bodies of any shape determined by the cross-sectional shape of the hollow part of the mold without friction with the inner wall of the mold by creating a slope that widens toward the exit.

Generally, the surface of an ingot is not completely smooth, but has irregularities, and often has local 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. To remove defects, the ingot is usually cut into bars,
Prior to plastic working such as forging and rolling to form wires, plates, tubes, etc., the surface layer is ground or scratched. Further, 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 a single block without surface defects from the standpoint of omitting the grinding process and improving the yield of the ingot.

In continuous casting of steel and aluminum ingots, the mold is usually required to slide. This is because when the solidified shell of the cast metal adheres to the inner wall of the mold, the movement of the solidified shell toward the exit within the mold is obstructed, and so-called breakout occurs due to the destruction of the solidified shell. This is because the solidified molten metal will gush out. Such breakout is more likely to occur in alloys with a wide solidification temperature range. For example, continuous casting of cast iron or steel with a high sulfur concentration is considered extremely difficult.

3- It has been strongly desired to develop a continuous casting method for alloys that are prone to such breakouts.

The object of the present invention is to provide a continuous casting method for all metals and alloys to obtain rod-shaped, plate-shaped, and tubular ingots having smooth surfaces without surface defects without damaging the inner wall of the mold. .

That is, in the present invention, the temperature of the inner wall surface of the mold can be controlled by immersing a hollow mold having an inner wall surface with a slope of 9 degrees widening toward the outlet into the surface of the molten metal, or by incorporating a heating element in the hollow mold. A rod-shaped rod that is cast by maintaining the temperature above the solidification temperature of the cast metal, preventing the formation of a solidified shell on the side wall of the mold, and starting solidification as soon as the cast metal exits the mold.

This is a continuous casting method for ingots of any cross-sectional shape, such as a plate shape or a tube shape, and a continuous casting device used therein, which has a mold having an inner wall surface that widens toward the outlet and has a slope.

FIG. 1 is a vertical cross-sectional front view showing one embodiment of a continuous casting apparatus for carrying out the present invention.

■ is a molten metal holding furnace, ■ is a molten metal, and the molten metal level is maintained constant. ■ is a mold whose inner wall surface has a slope that spreads upward, and the upper end of the hollow part is immersed and maintained below the molten metal level. There is a connection ■ that plays a role. ■ is a support for the mold. ■ is an ingot dummy, which is cooled by air, gas, mist, water, etc. injected from the coolant spray (■). ■ is a shielding plate to prevent radiant heat from the molten metal. After bringing the ingot dummy (■) into contact with the hot water surface in the hollow part of the mold (■),
The [phase] ingot can be obtained by pulling it up with the rotation of the pinch rolls.

A feature of the present invention is that the inner wall surface of the heated hollow mold has a widening slope toward the outlet, so that even if the cooling rate of the ingot dummy is too high, the molten metal will not flow inside the mold. Even if solidification occurs, the ingot can be pulled out of the mold without destroying the inner wall of the mold. If such a slope of the inner wall toward the outlet does not exist, various factors should be taken to prevent the bath water from solidifying within the mold and scratching the ingot surface due to friction with the mold inner wall. Must be strictly controlled. These five factors include the solidification temperature of the metal or alloy to be cast;
The temperature of the molten metal in the holding furnace, the cooling and pulling rate of the ingot,
Although there are factors such as the size of the ingot, the cooling of the ingot and the conditions for pulling the ingot are the most important factors, compared to the pulling speed.
If the degree of cooling is too great, there is a risk that the ingot will solidify within the mold and adhere to the side walls of the mold, destroying the mold. According to the method of the invention, rod-shaped, plate-shaped,
Continuous casting of tubular ingots can be easily performed.

According to the method of the present invention, the internal structure becomes a fiber structure consisting of elongated columnar crystals, making it an extremely suitable method for producing materials that require a unidirectional solidification structure, such as magnets, silicon steel plates, and eutectic composite materials. In addition, depending on the cross-sectional shape of the hollow part of the mold used in the method of the present invention, ingots of arbitrary shapes can be obtained, and wires, rods, plates, and tubes can be manufactured directly from the molten metal.

The mold referred to in the present invention differs from the concept of conventional molds, in which bath water is solidified in the mold to produce ingots and castings.The molten metal does not form a solidified shell in the mold, and at the exit of the mold, it is eventually cast. This is a mold for adjusting the shape of the molten metal 61 to be solidified as a lump.

In implementing the present invention, it is important that the upper end of the hollow mold be maintained at the same height as or slightly below the molten metal level, and that the temperature of the inner wall surface be maintained above the solidification temperature of the molten metal. The material and wall thickness of the mold must be completely returned so that it can sag. For example, alloys with low solidification temperatures such as graphite, silicon carbide, and boron nitride can be used for aluminum alloys and copper alloys, and alumina, silica, chromium oxide, and beryllia can be used for steel, cast iron, and alloys with high melting points. , magnesia, tolya, zirconia, boron nitride,
A refractory material mainly composed of silicon carbide or silicon nitride can be used. In addition, for casting aluminum and magnesium alloys, tungsten, tantalum, or other metal-based alloy molds can be used; for low-melting metals such as tin alloys, glass molds can be used. However, when making this selection, you must choose a material that will not react with and corrode the bath metal.

71 The method of the present invention is particularly superior to the conventional continuous casting method by providing the inner wall surface of the mold with a full slope of expansion toward the outlet, thereby reducing damage caused by friction on the inner wall of the mold. It is possible to continuously cast metal and alloy wire, rod, plate and tubular metal materials without risk.

The present invention is not only extremely useful for improving the surface condition of ingots, but also eliminates the need for equipment and energy for sliding the mold, which were required in conventional methods, and also makes it possible to continuously improve the surface condition of steel ingots. In casting, vitreous surface additives have often been used to lubricate molds and ingots, but 6D, rod-shaped, plate-shaped, and tubular ingots have the advantage of eliminating the need for vitreous surface additives. This is a revolutionary method for continuous casting.

4 An additional related original invention is that the temperature of the inner wall surface of the outlet of the mold for supplying molten metal from one end and continuously obtaining ingots from the other end is maintained at a temperature higher than the solidification temperature of the cast metal. Concerning continuous casting method for metal ingots featuring features 8- In order to prevent destruction of the outlet of the mold for the original invention, the present invention uses a mold having a hollow inner wall surface extending toward the exit and having a slope. This is an application of the original invention that requires the temperature of the inner wall surface of the exit of the mold to be higher than the solidification temperature of the cast metal, and the present invention would not exist without the use of the original invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectional view of a main part showing one embodiment of the present invention. ■ Molten metal holding furnace ■ Ingot dummy ■ Molten metal ■ Coolant spray ■ Mold ■ Shielding plate ■ Edge of mold ■ Vinci roll ■ Support tool

Claims (1)

[Scope of Claims] L A continuous metal mold for supplying molten metal from one end and suspending the metal molded body from the other end, characterized in that the inner wall surface of the mold has a sloped metal mold that widens toward the outlet. Casting method 2 Mold for continuous metal casting characterized by having a gradient die whose inner wall surface widens toward the exit of the metal molded body 3 A hollow mold whose inner wall surface has a gradient that widens toward the exit of the metal molded body Continuous casting apparatus characterized by 4. A large upward continuous casting method for metals characterized by a hollow die having a sloped die whose inner wall surface spreads upward, and which is immersed in the surface of the molten metal 5. Having an inner wall surface which spreads upward. Upward type continuous metal casting apparatus 1-, characterized in that a hollow mold is immersed in the surface of molten metal.