JPS59185551A - Casting mold for continuous casting and rust-preventive processing method thereof - Google Patents

Abstract

PURPOSE:To provide rust prevention to a mold frame and to obtain a continuous casting mold having excellent durability by forming a protective film consisting of a corrosion-resistant metal on the surface of said frame in contact with the outside wall surface of a mold base provided with slit grooves for cooling water. CONSTITUTION:A mold for continuous casting is constituted by providing plural slit grooves 5 for cooling water on the outside wall surface of a mold base 3 consisting of copper, etc., forming grooves 6, 7 for feeding and discharging the cooling water on the inside wall surface of a mold frame 1 consisting of an ordinary steel, etc. in contact therewith via the O-rings 12 disposed in the O-ring grooves 11 of a corrosion-resistant metallic layer 11, and distributing the cooling water passed through a supply port 8 to a discharging port 9 into the cooling water passage formed of said grooves 5 and the inside wall surface of the frame 1 thereby cooling the base 3. A protective film 10 consisting of a corrosion-resistant metal such as a stainless steel is formed by melt spraying, etc. on the surface of the frame of such mold for continuous casting. The corrosion of the frame 1 owing to the high-temp. cooling water is thus prevented and the durability of the mold is improved.

Description

[Detailed description of the invention] Regarding the law.

In general, molds used for continuous casting of low carbon steel, high carbon steel, stainless steel, or special steel have a mold base made of copper or copper alloy, and an ordinary steel basin that supplies cooling water to cool the mold base. It consists of a mold frame consisting of. In this type of continuous casting mold, in order to cool the mold base, multiple slit grooves are provided on the surface opposite to the wall surface where the mold base contacts the molten steel, that is, on the outer wall surface of the mold base, and the mold base and mold frame are A cooling water passage is formed by the mold frame, and the cooling water is distributed and made to flow through the cooling water supply/discharge groove provided in the mold frame. However, because the molten steel injected into the continuous casting mold is at a high temperature of more than 10-100 degrees, the wall surface of the mold frame that comes into contact with the cooling water erodes, causing adjacent cooling water passages to communicate with each other and the flow rate of the cooling water to decrease. If the cooling rate becomes slower than the set value, the cooling efficiency decreases, resulting in a decrease in the quality of the cast product.To avoid this, casting must be stopped and the mold frame must be replaced frequently. The present invention was made in view of the above-mentioned problems, and aims to prevent corrosion of continuous casting molds, especially the mold frame, by cooling water, and to improve durability. The main object of the present invention is to provide a continuous casting mold with excellent performance.The gist of the present invention is to provide a mold base having cooling water slit grooves on the outer wall surface, and a mold base that is closely connected to the outer wall surface of the mold base. A continuous casting mold comprising a mold frame having a cooling water supply/discharge groove for supplying or discharging cooling water to or from the cooling water slit groove. A continuous casting mold is characterized in that a protective coating is formed thereon.

That is, the present invention solves the above technical problem by protecting the surface of a mold frame made of an easily corroded material such as ordinary steel with a corrosion-resistant metal.

The corrosion-resistant material used is preferably stainless steel or aluminum and its alloys.

In a preferred embodiment of the invention, an O-ring groove for accommodating an O-ring that seals between the mold base and the mold frame is formed in a corrosion-resistant metal layer overlaid on the peripheral edge of the mold frame. Note that it is preferable to form a protective film made of the above-mentioned corrosion-resistant metal also on the surface of this corrosion-resistant metal layer.

According to the invention, the protective coating is formed by thermal spraying a corrosion-resistant metal.

Embodiments of the present invention will be described below with reference to the accompanying drawings. In the drawings, 1 is a mold frame on the long side, 2 is a mold frame on the short side, 3 is a mold base on the long side, and 4 is the short side. Corresponding mold bases 3.4 are fixed to the inner wall surfaces of the long-side and short-side mold frames 1.2 by bolts, respectively.

The long side and the short side have the same structure, so to explain the long side as an example, the mold base 3 is made of copper, and its outer wall surface, that is, the surface in contact with the inner wall surface of the mold frame 1, is made of copper. A plurality of cooling water slit grooves 5 are formed. Cooling water supply/discharge grooves 6 and 7 are formed on the inner wall surface of the mold frame along its longitudinal direction at its lower and upper ends, respectively, and the cooling water is supplied from a cooling water supply port 8 formed at its lower end. The cooled water is distributed through the supply/discharge groove 6 to cooling water passages of the number of layers formed by the slit groove 5 of the mold base 3 and the inner wall surface of the mold frame l, and flows through each passage to the mold base. After the cooling water 3 is cooled, they join together at the cooling water supply/discharge groove 7 and are discharged from the cooling water outlet 9 to the outside of the mold. Since the mold frame 1 that comes into contact with this cooling water is usually made of ordinary steel, in order to prevent corrosion of the mold frame 1, the inner wall surface (cooling water supply and drainage groove 6) that is in close contact with the outer wall surface of the mold base of the mold frame 1 is A protective coating 10 is formed on the surface (including the .70 surface). This protective coating 10 is formed by, for example, melting wire-shaped metal using an electric arc, atomizing it with compressed air, and injecting the atomized molten metal particles onto the inner wall surface of the mold frame 1. This can be obtained by letting

When using aluminum as a corrosion-resistant metal, 01~
It is preferable to form a film of approximately 0.02 dragon thickness, but if it is necessary to form a thicker protective film, for example,
When repairing a mold frame that has been corroded and worn by cooling water, it is best to first apply Ni-Al1 alloy and then top it with aluminum or 18-8 stainless steel, or use a corrosion-resistant, low-shrink material in the middle layer. alloy (e.g. 13% Cr
It is preferable to form a coating by applying a coating such as stainless steel.

Furthermore, in order to prevent water from leaking between the mold frame 1 and the mold base 3, an O-ring groove 11 is usually provided in the mold frame 1, and a KO ring 12 is attached to the groove. As shown in the figure, stainless steel or the like is built up in the recess provided in the region where the O-ring groove 11 of the mold frame is to be formed (in FIG. is formed, and an O-ring groove 11 is formed in this.
By forming this, the corrosion resistance against water can be further improved. It is also preferable to form a corrosion-resistant metal layer in the region where the bolt holes 14 are to be drilled. In the illustrated embodiment, the protective coating 1 is also applied on the corrosion-resistant metal layer 13 that has been overlay-welded.
0 is formed.

By the way, Ni-A1 alloy was thermally sprayed to a thickness of 0.2 mm as a bonding material on the entire inner wall surface 1a of the mold frame made of ordinary steel, and stainless steel (5US308) was sprayed on top of it to a thickness of 23 mm.
After spraying it to a thick layer, it was finished to form a protective coating, and when this mold frame was assembled with a mold base and continuously cast as a mold, no water erosion was observed even after 3 years had elapsed.

As explained above, the present invention is achieved by forming a protective coating made of a corrosion-resistant metal on the inner wall surface of the mold frame made of a material lacking in corrosion resistance such as ordinary steel, that is, on the surface of the mold frame in contact with the outer wall surface of the mold base. , it is possible to prevent corrosion of the mold frame by cooling water, significantly improve the ml longevity of the mold, enable continuous casting over a long period of time, and maintain high quality of the product over a long period of time. .

[Brief explanation of drawings]

1+1-1: A schematic plan view of a continuous casting mold according to the present invention, FIG. 2 is a front view of the mold frame, and FIG. 3 is a sectional view taken along the line III--III in FIG. 1. 1.2 Mold frame, 3, 4 Mold base, 5 Cooling water slit groove, 6, 7 Cooling water supply/discharge groove, 10 Protective coating, ]] 1-O ring groove 120 ring, 13 Corrosion-resistant metal layer

Claims (2)

[Claims] (1) A mold base having a cooling water slit groove on the outer wall surface, and a mold frame having a cooling water supply/drain groove that is in close contact with the outer wall surface of the mold base and supplies or discharges cooling water to the cooling water slit groove. 1. A continuous casting mold comprising: a protective coating made of a corrosion-resistant metal formed on the surface of the mold frame in contact with the outer wall surface of the mold base. (2) Prior to assembling a mold frame having a cooling water supply/discharge groove for supplying or discharging cooling water to or from the cooling water slit groove in close contact with a mold base having a cooling water slit groove on the outer wall surface, A method of rust-proofing a mold for continuous casting, characterized by forming a protective film by thermally spraying a corrosion-resistant coating on the surface in contact with the outer wall surface of a mold base of a frame.