JPS5841663A - Method and device for casting molten metal of steel in form of slab - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for forming molten slabs of steel and an apparatus for carrying out the method.

Arc-type casting equipment for continuously casting slabs is known. In conventional continuous casting equipment, molten metal is poured from above into a straight or arcuate mold that is installed vertically or obliquely, and is partially solidified.-C There is.

Next, 1. The continuous cast material, whose interior is still in a fluid state, is guided in an arc shape to a guide stand, and after it stops passing through the arc region within μ, it is straightened, and then horizontally It is designed to guide you. Due to the static pressure caused by the remaining molten steel in the cast bar, the shell of the cast bar deforms between the supporting elements. In the region of final solidification, segregation occurs at the center of the tip of the tundama due to the nine flow associated with final solidification. In this region, additional special measures can be taken to directly cool the continuous cast material1 to reduce blistering, or to reduce the flow state by subjecting the continuous cast material to a very slight rolling deformation in the final solidification region, or to reduce the flow conditions by applying a magnetic field. It is well known that the effects of these drugs can be used to improve tissues. However, since segregation at the center cannot be avoided by such measures, it is a problem that must be solved to reduce the segregation that occurs at the center. Rapid cooling causes cracks in the boundary m1, and too strong rolling deformation may cause internal cracks, so there are restrictions on applying the above method from the viewpoint of quality.

Therefore, the object of the present invention is to eliminate the above-mentioned drawbacks and at the same time avoid the blistering caused by continuous casting, and also to prevent the internal part of the continuous casting material which is in a liquid state in relation to the blistering of the continuous casting material in the region of the tip of the molten metal pool. An object of the present invention is to provide a method and apparatus for avoiding the occurrence of flow.

In order to achieve the above object, claims 1 and 2
The method and apparatus described in the Characteristics section of the present invention have been proposed in accordance with the present invention.

Reference is made to claims 3 and 4 for preferred embodiments of the invention.

In manufacturing pipes by continuous casting without the use of mandrels, the continuous material is guided along an arc of 270° or 270°, and depending on the type of pipe, the liquid part extends over a semicircle and It is known to use the continuous cast material shell remaining in the area of the circle to form the required pipe.

In the case of this known method, the problems mentioned at the beginning of central deviation and 1 do not occur, since the residual molten metal which segregates is removed from the inside of the pipe.

A feature of the method according to the present invention is that no load is applied to the outer skin of the continuously cast material due to the static pressure caused by the molten steel in the region of the tip of the molten metal in the musky state. The static pressure caused by the molten steel does not have a disadvantageous effect in two ways. One of them is to apply a load to the roller, and the support roller bends under the action of this mechanical load and the thermal load from contact with the surface of the slab. In extreme cases, if the curvature exceeds the elastic limit, the material of the roller will flex and a deformation will remain. If the roller is damaged in this way, the cross-sectional shape of the continuously cast material will be deformed. The resulting flow causes segregation in the center.

On the other hand, under the action of the static pressure of the molten steel, two supports
The outer skin of the continuously cast material swells between the rollers1, and while the above behavior is repeated over and over again, an undesirable flow of molten steel occurs at the tip of the sump.

An example of the features of the method proposed according to the present invention will be explained as follows.

The static pressure due to the molten steel at the sump tip of a continuous casting installation with a radius of 10°51?1 was 7.3 bar. Roller spacing is 500 wb and slab width is 2
000g, the load on the skin between the two rollers is 73 MP, and similarly the load on the roller is 7.
It was 3 MP. According to the method according to the invention, this load could be reduced to zero.

FIG. 1 conceptually illustrates a general example. It is something that

Slabs with a thickness of 250 wm are cast in a continuous casting installation with a radius of 8.0 m at a casting speed of 1.5 m/min. When secondary cooling is carried out normally, the solidification number is 24s+s·-1% and the solidification time is 27.1 minutes. The length of the pool under the above conditions is 40.1 m.

The angle α can be expressed by the following formula, that is, ct=11 in this case. Here, R is the radius of the device, and LsN is the length of the bathtub.

Continuous casting equipment can be designed in the same manner with respect to bed radius, slab thickness, casting speed, and cooling rate. When conditions change, the inclination of the continuous casting material guide path can be adjusted by changing the inclination angle.

[Brief explanation of the drawing]

The drawing is a conceptual overview or route map of the configuration of the device according to the present invention.

Claims (4)

[Claims] (1) It is provided with an arc-shaped continuous casting material guide extending over an arc of 'A' or about a circle and transitioning to a straight casting material guide, and 1 is installed almost vertically. In a method of casting molten steel in the form of a slab using continuous casting equipment, the molten steel is supplied to the upper end of a continuous casting mold with an open top. The molten metal level in the entire room and #1 are maintained at the same height, and the thickness of the continuous casting material and the descending speed of the continuous casting material are adjusted so that the continuous casting material solidifies on the surface where the molten metal liquid level is located. and the slope of the straight guide with respect to the horizontal plane is selected in conjunction with the cooling conditions. (2) Continuous casting mold with open top and A or approx.
Claim 1 comprising a continuous casting material guide extending over an arc of a circle, a straightening device, and one continuous casting material guide.
An apparatus for carrying out the method described in paragraph 1, wherein the continuous casting material guide starts from the mold and is guided in an arc shape forming an angle α with respect to the vertical plane to the tool or an arc of approximately A circle, and the upper Apparatus characterized in that a straightening device is arranged behind said arcuate section so that the straight continuous casting material guide section extending toward the end terminates in a horizontal plane positioned to pass through the mold. (3) A series of U pairs of straight continuous casting guide sections arranged opposite each other along the wide side of the slab.
- The device according to claim 2, characterized in that it is constructed in a manner known from Rasho. (4) The slope α of the continuous casting material guide path can be changed,
The apparatus according to claim 2 or 3, characterized in that K can be made to match casting conditions.