JPH04224055A - Continuous casting method - Google Patents

Abstract

PURPOSE:To restrain solidification and oxidation on surface of molten steel developing at the time of casting by setting a heat insulating plate covering the molten steel surface held with a mold and injecting on inert gas between the molten steel and the heat insulating plate. CONSTITUTION:The heat insulating plate 3 having shape corresponding to mold shape formed with metallic belts 1 and blocks 2, is set on the molten steel surface 4 while supporting with a flat nozzle FN and an introducing pipe 5. The heat insulating plate 3 is made of non-metallic material having small, emission and small heat conductivity. Therefore, heat transferring quantity with radiation from the molten steel surface 4 is made to little and the lowering of the surface temp. is restrained and the solidification is not developed. Further, the inert gas is injected into space closed with the metallic belts 1, blocks 2, heat insulating plate 3 and the molten metal surface 4 from an introducing pipe 5 to restrain the oxidation of molten steel.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for keeping the surface of a molten metal warm and preventing oxidation of the molten metal without using continuous casting powder in a belt-type continuous casting method. The so-called present invention is a technology belonging to the field of belt-type continuous casting in which thin slabs having a thickness of 100 mm or less are obtained from molten metal (described below using the example of "molten steel") by continuous casting.

0002

[Prior Art] Conventionally, as a type of continuous casting, for example,
JP-A-58-107255, JP-A-60-166
A pair of endless metal belts facing each other with a predetermined interval in a partial area of a running route, and a metal belt sandwiched between the metal belts, disclosed in Japanese Patent Application Laid-Open No. 1-293956. A cross-sectional shape corresponding to the desired slab is formed by the thin slab and a pair of block groups that move synchronously, and these metal belts and block groups are moved along a predetermined movement path by guide rolls and guide rails. In addition to guiding and supporting it so that it moves circularly,
A jet nozzle and a cooling pad are arranged on the back side of the metal belt between each guide roll, and the metal belt is cooled by a fluid film formed by jetting cooling fluid on the back side of the metal belt, while the metal belt is injected from above the casting space. Molten steel is injected through a nozzle to generate a solidified shell along the mold wall of the metal belt or block group, and the slab produced by the growth of the solidified shell is pulled out from the casting space from the lower end via a guide roll. A belt-type continuous casting machine called a "belt caster" has been proposed.

[0003] In such a belt type continuous casting machine, there is no need to use continuous casting powder, which is used for the purpose of lubrication between the solidified shell and the mold in other fixed mold type continuous casting machines. This means that in a fixed mold type continuous casting machine, it is possible to prevent product defects caused by powder being dragged into molten steel during casting. However, casting methods that do not use powder pose problems with solidification and oxidation of the molten steel surface. The solidified shell on the surface of the molten steel, known as a deckle, deteriorates the surface quality of the slab, and if the molten steel on the surface between the metal belt and the injection nozzle solidifies and becomes one, it can cause damage to the nozzle as the metal belt moves. . Furthermore, when the surface of the molten steel is oxidized, the generated oxides are taken into the slab, which significantly impairs the surface quality of the slab.

0004

[Problems to be Solved by the Invention] The present invention improves the surface quality of continuously cast pieces by suppressing the solidification and oxidation of the surface of molten steel that occurs during casting using the belt type continuous casting machine. , the objective is to prevent damage to the injection nozzle.

[0005]

[Means for Solving the Problems] In order to solve the above problems, the present invention provides the following continuous casting method. In a belt type continuous casting machine, when continuously casting molten metal, a heat insulating plate is installed to cover the surface of the molten metal held by the mold, and gas is inserted between the molten metal and the heat insulating plate. Continuous casting method.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram showing an embodiment of the present invention. In FIG. 1, a heat insulating plate 3 having a shape corresponding to the mold shape formed by a metal belt 1 and a block 2 is supported by a flat nozzle FN, an introduction pipe 5, etc. and installed on a surface 4 of molten steel. The heat insulating board 3 is made of a non-metallic material with low emissivity and low thermal conductivity. This reduces the amount of radiant heat transfer from the molten steel surface 4, suppresses a decrease in surface temperature, and prevents solidification. Furthermore, in the present invention, an inert gas such as Ar or N2 for suppressing oxidation of the molten steel is inserted from the introduction pipe 5 into the space closed by the metal belt 1, the block 2, the heat insulating plate 3, and the molten steel surface 4. Steel was cast by the method of the present invention and the conventional method under the conditions shown in Table 1. According to the present invention, there was no nozzle damage, the casting was stable, and a slab with a good surface was obtained.

[0007]

[Table 1]

[0008]

[Effects of the Invention] As described above, the present invention improves the surface quality of continuously cast pieces by suppressing the solidification and oxidation of the molten steel surface that occurs during continuous casting using a belt type continuous casting machine. However, it has a great effect on the field of art, such as preventing damage to the injection nozzle.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of an embodiment of the method of the present invention,
(a) is a longitudinal cross-sectional view, (b) is a cross-sectional view, and (c) is a side cross-sectional view.

[Explanation of symbols]

1 Metal belt 2 Block 3　Insulation board 4 Molten steel surface 5 Introductory pipe

Claims (1)

[Claims] Claim 1: When continuously casting molten metal in a belt-type continuous casting machine, a heat insulating plate is installed to cover the surface of the molten metal held by the mold, and there is no space between the molten metal and the heat insulating plate. A continuous casting method characterized by the insertion of active gas.