JPS59199144A - Mold for continuous casting machine - Google Patents

Abstract

PURPOSE:To provide a titled mold which forms always a uniform solidified shell and prevents generation of a vertical cracking flaw in the longitudinal direction by forming a circular mold tube of a water-cooled mold case for continuous casting in such a way that said tube can rotate freely around the axis thereof. CONSTITUTION:A mold case 5 centering at a mold tube 1 is rotated slowly at a prescribed rotating speed by a driving gear 9 which is driven by a motor 10. A mechanism 11 for supplying cooling water which is supported by a bearing 12 cools the tube 1. The mold tube 1 rotates slowly and therefore even if mold powder fails to enter uniformly the space between the tube and a solidified shell 2 and even if the cooling is nonuniform and the wall thickness of the tube is nonuniform, the solidified shell 2 is made uniform over the entire circumference and the generation of a vertical cracking flaw is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mold for a continuous casting machine, and more particularly to a mold for a round billet continuous casting machine that is capable of forming a solidified shell of uniform thickness.

In recent years, attempts have been made to cast round billets as a material for seamless pipes using continuous casting machines.

Some of them have been put into practical use.

The structure of the above continuous casting machine for round billets is basically the same as that of a conventional continuous casting machine for slabs.

Problems when continuously casting round billets will be explained.

As shown in FIG. 1, when the thickness of the solidified shell 2 formed inside the mold tube 1' by cooling becomes uneven in the circumferential direction, thermal stress is applied to the thinnest part of the solidified shell 2. acts in a concentrated manner, as shown in FIG.

1. on the surface of round billet 3. Vertical cracks 4 occur in the longitudinal direction.

The reason why the thickness of the solidified shell 20 in the circumferential direction becomes non-uniform is that if the mold powder does not flow uniformly between the mold tube 1' and the solidified shell 2, the thickness of the solidified shell 20 becomes uneven in the circumferential direction. If the flow rate of the cooling water that cools the mold tube 1' becomes non-uniform, grooves may occur, or if the wall thickness of the mold tube 1' is non-uniform.

Currently, there is no best way to solve the problems mentioned above.

The present invention provides a mold for a round billet continuous casting machine that is capable of forming a solidified shell having a uniform circumferential thickness from the above-mentioned viewpoint.

A mold for a round billet continuous casting machine, comprising a mold case, a cylindrical mold tube vertically fixed to the center of the mold case, and a cooling means for cooling the mold tube.

The molded tube is characterized in that it is rotatable about its axis.

One embodiment of this invention will be described with reference to the drawings.

FIG. 3 is a longitudinal sectional view of a mold for a round billet continuous casting machine, which is an embodiment of the present invention.

In FIG. 3, reference numeral 1 denotes a cylindrical molded tube that is vertically fixed to the center of a molded case, which will be described later. 5 is a cylindrical molded case having flanges 5a at the upper and lower ends, and includes a support member (not shown).
It is rotatably supported in the horizontal direction. An inlet 5b and an outlet 5d through which cooling air passes are formed at the upper and lower parts of the body of the molded case 5. Said flange 5
Teeth 6 that mesh with a drive gear described later are formed over the entire circumference of a. Reference numeral 7 denotes a cooling water passage formed between the outer peripheral surface of the mold tube 1 and the mold cases 5 and 9. 8 is a drive mechanism for rotating the mold case 5 around its axis. The drive mechanism 8 includes a drive gear 9 that meshes with the teeth 6 of the flange 5a, and a motor 10 that rotationally drives the drive gear 9. A cooling water supply mechanism 11 is inserted through a plurality of bearings 12 and has a sealing function between the flanges 5a of the molded case 5. The cooling water supply mechanism 11 includes a support member (
(not shown), and has a cooling water inlet 11a and an outlet 11b'.

It is configured as described above. The operation of the mold for a continuous casting machine according to the present invention will be explained.

When the motor 10 is operated, the mold tube 1 rotates around the axis of the mold tube 1 together with the mold case 5. The cooling water.

From the inlet 11a of the cooling water supply mechanism 11 to the mold case 5
The water flows along one passage 7 from the bottom to the top through the inlet 5b formed in the body, and is discharged to the outside through the outlet 11b of the cooling water supply mechanism 11 from the outlet 5C formed in the body.

Molten steel, which is cooled by the above-mentioned cooling water and is poured into the rotating mold tube 1 from a tundish (not shown), comes into contact with the mold tube 1 and is cooled. The solidified shell 2 thus formed becomes thicker as it is pulled downward from the mold tube 1. This unsolidified round billet is further cooled in a secondary cooling zone and finally becomes a round billet as a product.

The solidified shell 2 inside the mold tube 1 contains mold powder because the mold tube 1 is constantly rotating at a predetermined rotation speed (1 to 10 times/min).

Even if the cooling water does not flow uniformly between the mold tube 1 and the solidified shell 2, the flow rate of the cooling water for cooling the mold tube 1 is uneven, or the wall thickness of the mold tube 1 is uneven. is also cooled uniformly.

Therefore, the thickness of the solidified shell 2 is uniform over the entire circumference, so that thermal stress acts uniformly on the solidified shell 2. As a result, no vertical cracks occur in the round let.

As explained above, according to the present invention, extremely useful effects such as being able to produce a round billet of excellent quality without vertical cracks are brought about.

[Brief explanation of drawings]

FIG. 1 is a horizontal cross-sectional view showing a solidified shell with non-uniform thickness inside the mold tube, FIG. 2 is a view of vertical cracks occurring on the surface of a round billet, and FIG. 3 is an embodiment of the present invention. FIG. In the drawing. 1.1'...Mold tube 2...Coagulated shell 3...Round billet 4...Vertical crack 5...
Mold case 5a...flange 5b...inlet 5c...outlet 6...teeth
7... Passage 8... Drive mechanism 9...
Drive gear 10...Motor 11...Cooling water supply mechanism 12...Bearing 13...Inlet 14...Outlet Applicant Nippon Koukan Co., Ltd. Agent Natsuo Shioya (and 2 others) Sho 1 Figure

Claims (1)

[Scope of Claims] The present invention is composed of a mold case, a cylindrical mold tube vertically fixed to the center of the mold case, and cooling means for cooling the mold tube. In molds for round billet continuous casting machines. A child caster for a continuous casting machine, characterized in that the mold tube is rotatable about its axis. .