JPH04224047A - Method and apparatus for producing continuously cast rod having spiral shape - Google Patents

Abstract

PURPOSE:To continuously cast a continuously cast rod having spiral outward appearance by using a mold for continuous casting having groove or projection, in which inner wall surface is spiral shape or is notched as spiral shape, and casting while executing rotating and drawing adapting itself to the spiral inclination. CONSTITUTION:A melting and holding furnace 1 has an exothermic body 2 and a molten metal holding crucible 3, and an aluminum 4 is melted and held. At side wall of the melting crucible, an assembled mold having a graphite-made heating part 5 building-in a mold heater 8, copper-made mold cooling part 6 water-cooled in inner part of the mold and asbestos cloth-made heat insulating part 7 for preventing heat transfer between the mold heater and the mold cooling part, is fitted. After confirming solidification at the cooling part, the continuous casting is executed at the prescribed drawing velocity while rotating a dummy block 9 and the continuously cast rod adapting themselves to the spiral shape in the inner wall face of mold. By this method, the long continuous rod having spiral outward appearance and no defect in the inner part, is continuously cast.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention has a spiral groove,
The present invention relates to a method and apparatus for producing a continuously cast bar that is sound and has few defects on its inner and outer surfaces.

0002

[Prior Art] As a method for obtaining a long rod having spiral grooves, for example, a thick rod is obtained by casting, etc., and then a square rod or a rod having linear grooves is obtained by using an extruder or the like. Methods of adding twists to both ends later, and methods of continuously carving spirals on the surface of the rod by rolling, etc. are known.

0003

[Problems to be Solved by the Invention] Even with these methods, it is possible to obtain a long rod with continuous spiral grooves by continuously feeding the raw material rod during extrusion, but it is difficult to obtain a long rod with continuous spiral grooves. It is difficult to avoid contamination due to extrusion lubricants and structural changes.

[0004] Although it is possible to join the respective end faces by welding or the like after extrusion processing, it is time-consuming and labor-intensive to detect the presence or absence of defects at the joint, and the spiral grooves at the joint may be deformed. However, the rework was a complex and difficult task.

[0005]

[Means for Solving the Problems] In view of the above circumstances, the present inventors have conducted intensive studies on an efficient manufacturing method for long rods having spiral grooves, and as a result, the present inventors have developed a method for producing long rods having spiral grooves. It was discovered that a long rod having a spiral groove can be obtained by casting while rotating the body or the mold part, and this led to the completion of the present invention.

That is, the present invention uses a continuous casting mold having a spiral inner wall surface or grooves or protrusions carved in a spiral shape on the inner wall surface, and performs casting while rotating and drawing in accordance with the spiral slope. A continuous casting method characterized by continuously obtaining a cast rod having a spiral groove, and an inner wall surface or the entire inner wall surface on the molten metal supply side of the continuous casting mold at a temperature lower than the solidification temperature of the metal to be cast. The above is heated by a heating element installed inside or outside the mold,
The present invention provides a continuous casting method and a continuous casting apparatus according to claim 1, characterized in that a mold having an integral structure or a combination structure in which the continuous casting rod extraction side is cooled to a solidification temperature or lower is used.

The present invention will be described in detail below. The present invention can be applied to all metals and their alloys, but the cast object immediately after solidification needs to withstand shearing force due to the rotation of the mold part or the rotation of the cast object itself, and the cast object must be made of pure metal or a small amount of alloy. Systems containing elements are more suitable.

[0008] The rotation for obtaining a helical cast rod is obtained by pulling out the cast object while rotating it in accordance with the helical gradient. If the cast bar is long, the rod may be wound around a jig such as a spool or bobbin, and the entire winding jig may be rotated.

[0009] Instead of rotating the cast bar, a cast bar having spiral grooves can be continuously obtained by pulling out the cast bar while rotating the mold part in accordance with the helical gradient.

[0010] As the rotation mechanism in the present invention, a mechanism for rotating the mold section, a mechanism for rotating the winding jig, a mechanism for rotating the molten metal holding section for supplying molten metal and the mold section as one body, etc. can be used. .

[0011] If the long bar with spiral grooves has a small diameter, or if the spiral grooves are minute, the mold for continuous casting may be capable of unidirectional solidification in the opposite direction to the casting direction. The solidification interface shape is preferably such that solidification on the surface side of the cast rod tends to lag behind solidification at the center.

[0012] For this purpose, it is effective that the mold is composed of a cooling part below the solidification temperature of the metal to be cast and a heating part above the solidification temperature. Also, strengthening the cooling by directly spraying water on the outlet side of the cooling section is also effective in increasing the temperature difference.

[0013] In order to ensure unidirectional solidification, the larger the temperature difference between the heating section and the cooling section, the better, and for this purpose it is necessary to provide a heat insulating layer between the two.

[0014] Although the heating section can maintain the temperature above the solidification temperature of the molten metal by heat transfer from the molten metal holding section, it is not necessarily sufficient to achieve complete unidirectional solidification even if a heat insulating layer is provided between the heating section and the cooling section. Therefore, it is preferable to provide a heating element inside or outside the mold. As such a heating element, a heating element using electric resistance, a heating element using an induction coil, etc. can be used.

[0015] By using a mold having such a heating section, a heat insulating section, and a cooling section and performing continuous casting while rotating it in accordance with the spiral gradient, a continuously cast rod having a spiral groove can be easily produced through a simple process. It became possible to manufacture

Although the basic shape of the cross section of the mold in the present invention is a circle, any shape from a triangle to a polygon can be selected. For example, if the cross section is rectangular and the inner wall surface of the mold is spiral, a mold with a spiral appearance can be obtained. If the cross section is circular, a continuously cast rod having spiral grooves can be obtained by using a mold having spiral grooves or protrusions cut into the inner wall surface of the mold.

[0017] The shape of the spiral groove of the continuously cast rod obtained in the present invention can be selected from any shape as long as it can be drawn out.

The present invention will be explained in detail below with reference to Examples, but the present invention is not limited thereto.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an example of a casting apparatus for carrying out the method of the present invention, and shows the situation at the start of casting. The melting and holding furnace 1 has a heating element 2 and a molten metal holding crucible 3, in which molten aluminum 4 is melted and held. The side wall of the melting crucible is a combination of a graphite heating section 5 with a built-in mold heating heater 8, a mold cooling section 6 made of copper whose interior is water-cooled, and a heat insulating section 7 made of asbestos cloth with a thickness of 1 mm to obstruct heat transfer between them. The mold is installed.

In this embodiment, the mold is installed horizontally, but the following operations can be performed in exactly the same way even if a similar mold is installed directly downward at the bottom of the crucible. The inner diameter of the mold is 30m
One triangular linear protrusion with a height of 5 mm, a base of 10 mm, and a pitch of 60 mm is carved into the inner wall of mφ.

At the start of casting, it is necessary to use a dummy block 9 to prevent the molten aluminum from leaking out of the mold. The molten aluminum that filled the mold solidifies in the cooling section and is strongly joined to the dummy block. Solidification progresses to the adiabatic part, but the heating part is set several degrees higher than the solidification temperature of aluminum by a separate temperature control device, so solidification does not proceed any further, but cooling due to heat transfer from the solidification part occurs. Therefore, the shape of the solidification interface becomes slightly convex in the direction of progression.

After confirming the solidification of the cooling part, 50mm/m
Continuous casting was performed while rotating the dummy block and the continuous casting rod in accordance with the spiral shape of the inner wall surface of the mold at a drawing speed of in.

FIG. 2 shows a pair of rotating and rotating drawing rolls 11.
Continuously cast rod 12 with a spiral groove on the continuously cast outer wall.
Shows the appearance.

The appearance of the obtained continuously cast bar completely reproduced the smooth spiral, and there were no internal defects such as shrinkage cavities.

[0025]

As described above, according to the present invention, a long continuous bar having a spiral appearance and no internal defects can be continuously cast, and its industrial value is extremely large.

[0026]

[Brief explanation of the drawing]

FIG. 1 is a side sectional view at the start of continuous casting using a combined heating and cooling mold device.

FIG. 2 is a side sectional view of a mold device during casting and an external view of a continuously cast rod.

[Explanation of symbols]

1. Melting and holding furnace
7. Heat insulation part 2. heater
8. Mold heating heater 3. Molten metal holding crucible
9. Dummy block 4. molten aluminum
10. Spiral protrusions on the inner wall of the mold 5. Mold heating section
11. Rotary drawing roll pair

Claims (3)

[Claims] Claim 1: Using a continuous casting mold with a spiral inner wall surface or grooves or protrusions carved in a spiral shape on the inner wall surface, casting is performed while rotating and drawing in accordance with the spiral slope. A continuous casting method characterized by continuously obtaining cast rods having grooves in the shape of the shape. [Claim 2] The inner wall surface or the whole of the continuous casting mold on the molten metal supply side is heated to a temperature higher than the solidification temperature of the metal to be cast by a heating element installed inside or outside the mold, and the continuous casting rod extraction side is solidified. 2. The continuous casting method according to claim 1, characterized in that a mold having an integral structure or a combination structure that is cooled to a temperature below that temperature is used. 3. The continuous casting apparatus according to claim 1 or 2.