JPS62176641A - Core enshroud continuous casting method - Google Patents

Abstract

PURPOSE:To improve productivity of casting slab by inserting a core, which is penetrated through combined mold connected with an intermediate vessel, keeping a molten metal to pour in the intermediate vessel and also drawing the casting slab together with the core in a body, while vibrating the mold. CONSTITUTION:The intermediate vessel 2 is arranged at above the mold 1 and an insulating ring 3 is inserted between both. A positioning guide 6 is arranged in the vessel 2, and the core 5 is penetrated through the guide 6, and a core enclosing ring 7 is arranged at near the molten metal surface position in the vessel 2. Non-active gas is blowed on a boundary surface between the core 5 and the molten metal from a pipe 8, while pouring the molten metal, so as to keep the molten metal surface at a position of the core enclosing ring 7. Next, a casting is executed by drawing the slab 9 and the core 5 at the same time, while vibrating the mold 1 and the vessel 2 at vertical direction. As friction between the slab 9 and the mold 1 is reduced, casting speed is quickened. Therefore, productivity of the slab 9 is improved.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a clad slab or a hollow slab that is cast by connecting an intermediate container to the upper part of a mold and passing a core through the mold and the intermediate container. The present invention relates to a continuous casting method.

[Conventional technology]

In the conventional continuous casting method, the method of manufacturing the core while casting can be summarized into the following two points.

■ By integrating the tundish and mold, the tundish and mold are integrated.
A method of continuously injecting molten steel while inserting a metal pipe into a mold, and casting slabs by intermittent drawing with stops.

■ A steel pipe is connected or continuously supplied to the center of the mold, and molten steel is continuously injected from the kundish through the injection pipe between the mold wall and the steel pipe, and the mold is vibrated in the vertical direction while casting. A method of simultaneously and continuously drawing and casting a piece and a steel pipe (for example, JP-A-58-224049).

[Problem that the invention seeks to solve]

However, these conventional casting methods have the following drawbacks.

■The method of inserting a metal tube in the intermittent casting method can increase the average casting speed in order to ensure lubrication between the mold and the solidified shell and to prevent breakouts by generating a uniform solidified shell. 100~200w/mi
There is a drawing speed limit for n, and productivity is extremely low.

In the steel pipe insertion method in the continuous casting method (2), since molten steel is continuously injected into the mold from the tundish through the injection pipe, there is a drawback that the mold-core size is limited by the injection pipe size.

The present invention enables high productivity while casting the core into molten metal.
Clad slabs with excellent surface and inner surface properties, or
A method of manufacturing a hollow slab is provided.

[Means and operations for solving the problems] FIG. 1 shows an example of an apparatus for carrying out the present invention.

The intermediate container 2 is placed on the mold l, and the mold l and the intermediate container 2
Insert a heat insulating ring 3 between the

Before starting casting, the core 5 is fixed to the dummy par 4, a positioning guide 6 is installed in the intermediate container 2, and the core 5 is passed through the guide. A core enclosing ring 7 is installed near the hot water level of the intermediate container 2, and the core enclosing ring 7 and/or the core 5
Gas is blown onto the interface between the molten metal and the molten metal using a gas blowing pipe 8. The molten metal is injected from a ladle (not shown) or a larger intermediate container through an injection pipe. While pouring so that the molten metal level is maintained at the core surrounding ring position in the intermediate vessel 2, drawing of the slab 9 is started. Mold 1 and intermediate container 2
While simultaneously vibrating in the vertical direction, the cast slab 9 and the core 5 fixed to the dummy par are simultaneously pulled out and cast. Solidification begins below the insulating ring 3 set at the junction of the mold l and the intermediate vessel 2.

The features of the structure and operation of the method of the present invention will be explained in detail below.

The solidification start position within the mold 1 is controlled by an insulating ring 3 placed on the mold 1, and the mold 1 and the slab 9 are separated by continuously pulling out the slab 9 while vibrating the mold 1 in the vertical direction. This reduces the friction between the parts and enables high-speed casting.

In addition, by connecting the mold 1 and the intermediate container 2 and injecting into the intermediate container 2 through an injection pipe (not shown), the molten metal can be uniformly supplied around the core regardless of the mold size or the core size. As a result, the solidified shell is produced uniformly and has good internal properties.

Next, a means for inserting the core 5 into a predetermined position will be explained.

Before starting casting, the core 5 is fixed to the dummy par 4, and the core 5 is fed to a predetermined position by a core feeding device (not shown).

Furthermore, in order to accurately supply the core to a predetermined position, it is desirable to supply the core through a positioning guide 6 fixed directly above the intermediate container 2. Positioning guide 6 in intermediate container 2
When the mold 1 and the intermediate container 2 are fixed, the initially fixed insertion position does not change because the mold 1 and the intermediate container 2 are integrally connected. If the positioning guide 6 is not positioned directly above the intermediate container 2 but is fixed further above, the distance between the dummy par 4 and the positioning guide 6 becomes longer, and the eccentricity with respect to the set position for insertion into the slab tends to increase. .

Furthermore, in the continuous core casting method, if powder or scum 10 is floating on top of the molten metal, when the core 5 is inserted into the molten metal, it will be suspended on the surface of the core. Powder, scum, etc. 10 adhered to the core 5 may be poured into the casting, and solidification may end without being removed, resulting in defects between the cast slab 9 and the core 5. In order to prevent the occurrence of these defects, it is necessary to prevent floating objects (scum, powder, etc.) 10 from adhering to the molten metal around the core to be inserted. As a means of achieving this, a core enclosing ring 7 is installed and the hot water surface is sealed with an inert gas, or
Alternatively, an inert gas is directly blown onto the interface between the core 5 and the molten metal using the gas blowing pipe 8 to remove the generation of scum and the suspended matter 1O.

Further, the core surrounding ring 7 and inert gas blowing may be combined.

Further, when the size of the inserted core is small and horizontal buckling occurs due to its own weight in the molten metal, it is desirable to apply tensile stress to the core.

A solid core is used when producing a clay slab, and a hollow core is used when producing a hollow slab. Here, as the core material and the molten metal material, in addition to casting stainless steel into a carbon steel core shown in the embodiment, it is also possible to cast carbon steel into a stainless steel core. Furthermore, it is possible to manufacture various materials including ferrous alloys and non-ferrous alloys.

〔Example〕

(2) An intermediate container was set on top of a mold size of 150φ, a BN ring was installed at these joint points, and a carbon steel pipe of 40φ x 5t size was fixed to a dummy bar. 5US304
After injecting the molten steel into the intermediate vessel, onsillation cycle: 150 cpm.

Oncillation stroke: 611n, withdrawal speed 1
000 am/min to produce a hollow round bloom slab. The produced hollow round bloom slab had no eccentricity in the carbon steel tube that is the core, and was in good condition with no curling between the cast slab and the core.

■ Set the intermediate container on top of the mold size 700x160t, install the BN ring at these joint points, and
A carbon wI steel piece of X100t size was fixed to a dummy bar. After pouring molten steel of 5US304 into the intermediate vessel, onsillation cycle: 80 cpm, onsillage stroke: 3 mm.

Drawing speed: 800 am/min was used to cast carbon steel and stainless steel clad slabs. The resulting clad slab had good bondability between the boundary layer of the inner N: carbon steel and the outer N: stainless steel, and was also good with no entrainment.

〔Effect of the invention〕

According to the present invention, hollow cast slabs such as hollow round blooms or clad slabs can be manufactured continuously and with high productivity. The resulting core cast slabs such as hollow round blooms or clad slabs have good internal properties as well as the properties of the boundary layer, and are effective in obtaining core cast slabs of excellent quality at low cost.

[Brief explanation of drawings]

FIG. 1 is an example of an apparatus for carrying out the present invention. 1: Mold, 2: Intermediate container, 3: Heat insulating ring, 4: Dummy bar, 5: Core, 6: Positioning guide, 7: Core surrounding ring, 8: Gas blowing pipe, 9: Slab, lO: Floating matter on the molten metal (scum, etc.), 11: Cooling spray. Figure 1

Claims (4)

[Claims] (1) A core is inserted through an integrated combination mold in which an intermediate vessel is connected to the upper part of the mold, the molten metal is injected so that the molten metal level is maintained within the intermediate vessel, and the combination mold is vibrated. A continuous core casting method characterized in that the slab is pulled out integrally with the core. (2) The continuous core casting method according to claim 1, wherein the core is inserted through a positioning guide. (3) The continuous core casting method according to claim 1 or 2, characterized in that the core is inserted so as to be surrounded by a core surrounding ring at the level of the hot water. (4) Continuous casting of a core casting according to claim 1, 2, or 3, characterized in that the core is inserted while blowing gas onto the molten metal surface around the core. Law.