JPH0130578B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a horizontal continuous casting apparatus.

[Conventional technology]

In continuous steel casting equipment, electromagnetic stirring devices are used for the purpose of improving the quality of slabs.

In particular, when continuous casting is performed using a device in which a refractory pouring port for injecting molten steel from a tundish into a mold and a mold are installed in close contact with each other, electromagnetic stirring is applied to the molten steel in the mold, which is conventionally known. Instead, during casting, by electromagnetically stirring the molten steel entering the mold at the pouring spout, the molten steel at the joint from the spout to the mold is stirred and flows into the mold. A technology has been disclosed that aims to alleviate the sudden change in the cooling conditions of molten steel when it enters the slab, thereby eliminating the occurrence of abnormal solidification structures in the skin of the slab (Japanese Patent Application Laid-Open No. 135827-1989). (hereinafter referred to as "prior art").

[Problem to be solved by the invention]

However, in the above-mentioned prior art, the pouring spout (electric stirring zone) and the mold (cooling zone) were simply arranged side by side in an independent state, so dimensional accuracy such as pitch when assembling the two Although it is difficult to secure it, during long-term use, the pouring spout is simply made of refractory material, so the corners and joints can be scraped or chipped, and especially when used with molten metal, there are several drawbacks as shown below. existed.

1 Despite using electromagnetic stirring, it is still not possible to completely eliminate sudden changes in cooling conditions at thermal discontinuities, that is, at the joint between the pouring spout and the mold. It was not possible to eliminate all defects.

2 At the joint between the pouring spout and the mold, molten metal leaks from the joint, surface defects occur due to molten metal being inserted into the joint, and steps occur at the joint between the pouring spout and the mold due to poor centering between the pouring spout and the mold. However, there were many problems, such as surface defects caused by unevenness or unevenness, and operation stoppage due to failure in drawing the slab from the mold. It remained resolved.

3. In the prior art, it was difficult to cast pipe materials while effectively utilizing the effects of electric stirring.

That is, in order to maximize the electric stirring effect in casting pipe materials, the molten metal in the core mold must be stirred. To do this, the opening base end of the core mold must be tightly fitted into the opening (gate) or pouring spout of the tundish, but in the prior art, both the side wall of the tundish and the pouring spout were simply made of refractory material. Therefore, tight fitting of the core mold has been extremely difficult due to problems such as strength and installation dimensional accuracy.

Even if the proximal end of the core mold were tightly fitted into the proximal end of the mold in order to improve strength and precision, electric stirring would be performed on the molten metal before it penetrated into the core mold, and the most important point would be The electric stirring effect will not be applied to the molten metal in the child mold. This makes it impossible to manufacture pipe materials of good quality.

4 In the prior art, when switching from pipe material casting to round bar material casting, or even changing the dimensions (cross-sectional shape) of the cast material, the mold and pouring spout were each disassembled or replaced, and the pouring spout was reassembled. It is necessary to completely seal the molten metal between the tundish and the pouring spout and the mold, and this replacement and sealing work is extremely troublesome and requires skill.

5. In the prior art, in order to deal with multiple drawings of cast materials, the dimensions and shape of the pouring spout, etc. must be changed for each drawer according to the number of drawers, making it complicated to deal with multiple drawings. The drawbacks were that it was expensive and extremely difficult.

6. In the prior art, in order to cast sound castings, lubricant must be constantly forced into the mold so that the inner wall of the mold is coated with lubricant (vegetable oil, flux, etc.). It was hot.

In view of the above-mentioned situation in the prior art, the present inventors have conducted intensive research into improving the technology.In addition, the present inventors have also found that the quality of castings can be significantly improved, especially in horizontal continuous casting of copper or copper alloys. The purpose of this project was to develop a horizontal continuous casting device that could perform the following steps.

[Structure of the invention]

In order to achieve the above object, the present invention has a structure in which integrated graphite tubes whose inner diameter is shaped like the outer diameter of a cast slab are arranged in parallel from the base end side, and electromagnetic stirring is carried out through a heat insulating material on the outer periphery. The above-mentioned graphite pipe is divided into a molten metal lead pipe part integrally provided with the device and a mold body part integrally provided with a water-cooled mold on the outer periphery, and the molten metal lead pipe part and the mold body part are integrated. The base end was horizontally tightly fitted into the opening in the bottom side wall of the holding furnace, the molten metal in the metal introduction pipe was turned into a stirring rotational flow, and the molten metal in the stirring rotational flow was supplied into the mold body. That is the gist of it.

〔Example〕

The present invention will be explained below based on the drawings.

Figures 1 and 2 are schematic longitudinal sectional views of the sprue system of the apparatus according to the embodiment of the present invention, with Figure 1 illustrating the case when casting copper alloy billet material, and Figure 2 illustrating the case when casting copper alloy pipe material. be.

In the figure, 1 is a molten metal holding furnace wall, 2 is a graphite tube, 3 is a heat insulating material, 4 is an electromagnetic stirring device, 5 is a water cooling jacket, and 6 is a slab.

The graphite tube 2 has an inner diameter shaped like the outer diameter of the slab 6, and its proximal end 7 is tightly fitted into the opening 9 of the holding furnace wall 1 and is held so as to protrude horizontally. 10 has a length that is equivalent to the other end 11 of the water cooling jacket 5.

Thus, this graphite tube 2 is divided into two parts, a molten metal introduction pipe part 12 and a mold body part 13, in order from the holding furnace.
That is, the molten metal introduction pipe section 12 and the mold body section 13 are integrally connected by the graphite pipe 2 made of the same material.

In the hot water pipe section 12, the outer periphery is covered with the heat insulating material 3.
At the same time, an electromagnetic stirring device 4 (rotating coil in this example) is disposed via this heat insulating material 3.

In the mold main body part 13 which is parallel to the molten metal introduction pipe part 12, a water cooling jacket 5 is covered over almost the entire outer circumferential side of the mold body part 13, thereby forming a so-called water cooling mold part 14. The water-cooled mold section 14 is fixed horizontally as shown in the figure, and a water supply pipe 15 and a drain pipe 16 are connected to the water-cooled jacket 5.

When casting the pipe material, a core mold 17 is installed inside the graphite tube 2, as shown in FIG. This core mold 17 extends from the base end 7 of the graphite tube 2 to near the other end 10.
The graphite tube 2 is fixedly held by fitting the attachment base 18 of the graphite tube 7 into the base end 7 of the graphite tube 2 .

In the sprue system of the above embodiment configured in this way, the molten metal 19 discharged from the holding furnace is first stirred and rotated by the rotating magnetic field generated by the electromagnetic stirring device 4 in a state in which the molten metal 19 is not solidified at all in the molten metal introduction pipe section 12. , the water-cooled mold part 1 becomes a stirring rotational flow as shown by the arrow.
4.

This rotating flow of molten metal solidifies once it enters the water-cooled mold section 14, forming a slab 6 of a predetermined shape.

FIG. 3 is a schematic diagram of the macrometallic structure of the copper alloy pipe material 20 cast in this manner.

The pipe material 20 has fine and uniformly dispersed crystal grains 22, and is hardly affected by the temperature difference between the top and bottom inside the water-cooled mold, which is the fate of horizontal continuous casting. stands substantially perpendicular to the drawing direction indicated by the arrow, forming a uniform and substantially vertical coagulation zone 23, with no uneven thickness or bending, and the vacuum degree of the inner diameter is very good.

〔Effect of the invention〕

The device of the present invention consists of integrated graphite tubes whose inner diameters are shaped like the outer diameters of cast slabs, which are arranged in parallel from the base end side, and an electromagnetic stirring device is integrally provided on the outer periphery via a heat insulating material. The base end of the graphite tube is divided into a hot water pipe section and a mold main body section with a water-cooled mold integrally provided on the outer periphery, and the base end of the graphite pipe, which has an integral structure with this hot water introduction pipe section and the mold main body section, is placed at the bottom of the holding furnace. Since the molten metal is tightly fitted horizontally into the opening in the side wall, the molten metal coming out of the holding furnace is first subjected to rotational force by the rotating magnetic field generated by the electromagnetic stirring device in the molten metal guide pipe section, and becomes a stirring rotational flow. and supplied to the water-cooled mold section.

The device of the present invention exhibits the following unique effects.

(a) Thermal discontinuities that occurred in the prior art;
In other words, the sudden change in cooling conditions that occurs at the joint between the pouring spout and the mold is completely eliminated, the cooling conditions change smoothly, and the effect of electric stirring can be maximized. As a result, the solidification of the molten metal became extremely smooth, and it was possible to completely eliminate surface defects in the casting.

(b) In the prior art, the pouring spout (electric stirring zone) and the mold (cooling zone) are simply arranged side by side in an independent state, so dimensional accuracy such as pitch when assembling the two is difficult. While it is understandable that it is difficult to secure, during long-term use, since the pouring spout is simply made of refractory material, the corners and joints will be scraped or chipped, and the above-mentioned problems at the joints will inevitably occur when exposed to molten metal. There were many.

In contrast, in the device of the present invention, the electric stirring zone and the cooling zone are connected through a common graphite pipe, so the above-mentioned problems at so-called joints do not exist for molten metal. It stopped happening and was completely resolved.

(c) In the prior art, casting pipe materials was difficult both in terms of quality and technology due to the reasons mentioned above.

In contrast, with the device of the present invention, the base end of the core mold can be tightly fitted into the base end of the graphite tube with the base end facing the opening hole in the side wall of the bottom of the furnace. It is sturdy and can be installed with very high dimensional accuracy.

As a result, the molten metal in the core mold is located exactly at the molten metal guide pipe portion of the graphite pipe, and the stirring effect of the electric stirring device can be maximized.

In this way, with the device of the present invention, the installation position and installation strength of the core mold for manufacturing pipe materials are optimal, and the installation and removal operations are extremely easy as described below, and in addition, the quality is improved. It has the remarkable effect of being able to cast pipe materials of excellent quality.

(d) As mentioned above, since the device of the present invention has an integral structure through a common graphite tube (each part is treated as an integrated set without being separated), it has the following advantages: Is recognized.

Since the core mold can be easily installed by being inserted through the proximal opening of the graphite pipe, it is easy to cast the pipe material. In addition, even after pipe material is cast, the core mold can be easily removed by pushing it out from the other end to the proximal end without disassembling the set equipment, making it easy to switch to round bar casting. It's very simple.

When changing the dimensions (cross-sectional shape) of the cast material,
In the prior art, it is necessary to replace both the mold and the spout, and then completely seal the molten metal between the spout and the tundish, and between the spout and the mold.This replacement and sealing work is very tedious and requires a lot of skill. It was a task that required a lot of work.

In contrast, with the device of the present invention, the entire casting device, including each part, has an integrated structure, so all dimensions of the cast material can be changed by replacing each set, and difficult sealing work is not required. Very convenient.

When drawing multiple cast materials, in the case of the prior art, the dimensions and shape of the spout etc. had to be changed for each drawer depending on the number of drawers, making it difficult to handle multiple drawers. It was extremely difficult.

On the other hand, with the device of the present invention, the entire set of multiple pullers can be integrated into one set using the same concept as the above-mentioned integrated structure.
It has the advantage of being able to easily handle multiple pulls.

(e) In the prior art, in order to cast a sound casting, it was necessary to lubricate the inside of the mold by forcefully injecting a lubricant such as flux or vegetable oil such as rapeseed oil into the mold.

On the other hand, in the device of the present invention, the graphite tube itself has the effect of solid lubrication of carbon, so
It has the advantage that there is no need to forcefully lubricate the inside of the mold.

(f) The graphite tube used in the device of the present invention can easily achieve precision through lathe processing, and is also optimal in terms of hardness, strength, heat resistance, durability, dimensional accuracy, etc.

As explained above, according to the device of the present invention, the drawbacks of the prior art (Japanese Unexamined Patent Publication No. 53-135827) are eliminated at once, and in addition, the crystallization temperature is high and the difference in specific gravity is large compared to the matrix. Since intermetallic compounds can be uniformly dispersed and sound castings can be produced, this equipment is ideal for producing wear-resistant copper alloy castings with intermetallic compounds dispersed therein.

In addition, the copper or copper alloy billet material (round bar, square material) or pipe material manufactured by the apparatus of the present invention is
It has very good roundness and straightness, and especially the pipe material has very small thickness deviation. Furthermore, since the crystal grains were refined and uniformly dispersed, casting defects such as casting cavities and blowholes were significantly reduced, and a remarkable effect was seen in improving the quality inside the slab.

The electromagnetic stirring device used here is rotary coil type, linear coil type,
Effectiveness was observed in all solenoid coil types.

[Brief explanation of drawings]

Figures 1 and 2 are schematic vertical cross-sectional views of a sprue system of an apparatus according to an embodiment of the present invention, with Figure 1 illustrating the casting of copper alloy billet material and Figure 2 illustrating the casting of copper alloy pipe material. . FIG. 3 is a schematic diagram of the macroscopic structure of a cross section of a pipe material cast by the apparatus according to the embodiment of the present invention. 3... Heat insulating material, 4... Electromagnetic stirring device, 12... Molten metal introduction pipe section, 13... Mold main body section.

Claims (1)

[Claims] 1 Integral graphite pipes with an inner diameter shaped like the outer diameter of a cast slab are arranged in parallel from the base end side, and an electromagnetic stirring device is integrally provided on the outer periphery via a heat insulating material. The base end of the graphite pipe, which has an integral structure with the water-cooling mold and the mold main body, is connected to the opening in the bottom side wall of the holding furnace. 1. A horizontal continuous casting device, characterized in that the molten metal in the molten metal introduction pipe section is horizontally and tightly fitted, the molten metal in the molten metal introduction pipe section is turned into a stirring rotational flow, and the molten metal in the stirring rotational flow is supplied into the mold main body section.