JPS6027559Y2 - Continuous casting mold - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a mold for a continuous casting device.

When continuously casting metal, the molten metal is supplied from the tundish to the mold that penetrates vertically and is primarily cooled.
The part that is in contact with the mold becomes a solidified shell that gradually grows as it descends, and this solidified shell is pulled downward while rubbing against the inner surface of the mold.For example, if the mold is made of copper or When the molten metal is molten steel, copper pieces are scraped off from the inner surface of the copper mold by the solidified shell during drawing, and the scraped copper pieces are scraped off by the solidified shell. It will stick.

In this case, since the temperature of the solidified shell is higher than the melting temperature of copper,
As a result of the copper pieces adhering to the solidified shell melting and penetrating into the solidified shell, cracks called star cracks occurred on the surface of the continuously cast steel ingot.

Therefore, we decided to use nickel or nickel-based alloys, which have a high melting point, excellent heat resistance, and are less likely to be scraped off by the solidified shell than copper, and even if they are scraped off, they will not melt into the solidified shell. Continuous casting molds have been proposed in which the entire inner surface is coated to prevent star cracks from forming on the surface of the steel ingot, thereby producing a sound steel ingot.

However, as shown in Fig. 1, which is a vertical cross-sectional view of half of the continuous casting mold in which the entire inner surface of the copper mold is coated with nickel or nickel-based alloy (hereinafter collectively referred to as nickel), the tundish (Fig. The upper half IA of the copper mold body 1 that the molten steel injected from (not shown) comes into contact with first
In this case, the nickel coating layer 2 has a lower thermal conductivity than the copper mold body 1, and is therefore inferior in terms of heat removal effect, resulting in a higher temperature rise during continuous casting operation, and moreover, the molten steel The copper mold body 1, whose outer surface is strongly cooled by high-velocity water, is repeatedly heated by contact with the copper mold body 1, and the resulting thermal stress causes thermal fatigue and deterioration, resulting in cracks 3. There was a problem that it could no longer be used as a mold.

This idea was made in order to solve the problems of conventional continuous casting molds as mentioned above. In order to prevent cracks from occurring on the inner surface, a scraped part is provided inside the lower half of the mold body, and a coating layer of nickel or a nickel-based alloy is electrodeposited on the scraped part, so that copper or copper-based By forming the inner surface of the lower half that is continuous with the inner surface of the upper half that is still an alloy, it is possible to prevent scraping by the solidified shell, and in addition, the boundary between the inner surface of the upper half and the inner surface of the lower half is welded. This is a continuous casting mold that has good continuity between both halves by being integrated.

Next, the continuous casting mold of this invention will be explained by way of examples with reference to the drawings.

FIG. 2 shows an embodiment of the mold of this invention in a half longitudinal sectional front view.

As shown in the figure, in the mold of this invention, the inner surface 1a of the upper half of the mold body 1 made of copper or a copper-based alloy (e.g., Cu-Cr alloy, Cu-Cr-Zr alloy) is left bare without being coated. However, a coating layer 2 made of nickel or a nickel-based alloy is provided on the lower half, and the inner surface 2a of this coating layer 2 is continuous with the inner surface 1a of the upper half.

The coating layer 2 is formed to a sufficient thickness by electrodepositing nickel or a nickel-based alloy (thick electroplating method) on the scraped portion 4 formed inside the lower half of the mold body 1. This is what I did.

On the other hand, a weld bead 5 made of a Cu-Ni alloy is formed at the boundary between the inner surface 1a of the upper half and the inner surface 2a of the lower half made of nickel or a nickel-based alloy to ensure continuity between these two halves. It is assumed to be in good condition.

Next, the manufacturing mode of the mold of this invention will be explained with reference to process diagrams shown in longitudinal sectional front views of main parts in FIGS. 3a to 3e.

First, as shown in FIG. 3a, a cut-out portion 4 is formed inside the lower half of the mold body 1 made of copper or a copper-based alloy (hereinafter collectively referred to as copper).

Subsequently, as shown in the same figure, a coating layer 2 of nickel or a nickel-based alloy (hereinafter collectively referred to as nickel) is formed on the scraped portion 4 by electrodeposition.

Furthermore, as shown in Figure C, a groove 6 is formed at the boundary between the inner surface 1a of the upper half of the copper, which remains the bare surface, and the inner surface 2a of the lower half of nickel.

As shown in an enlarged view of a part of this groove 6 in FIG. It is designed to be removed.

After shaping the groove 6, as shown in Fig. 3d, Cu-
The Ni alloy weld bead 5 is shaped by gas metal arc welding to completely integrate the boundary between the copper mold body 1 and the nickel coating layer 2.

Finally, in addition to removing the excess buildup of the weld bead 5, a planing finish is applied to the weld bead 5 in order to ensure smooth continuity at the boundary between the inner surfaces 1a and 2a of the upper and lower halves. Complete.

Further, another manufacturing mode is similarly shown in process diagrams in FIGS. 5a to 5e.

In this manufacturing process, when forming the cut-off portion 4, no right-angled step is provided between it and the inner surface 1a of the upper half of the mold body 1;
Only at the point where the tapered portion 8 is formed, the above-mentioned FIG.
-e is different from the case (see Fig. 5C).

When the tapered portion 8 is formed, the electrodeposited nickel coating layer 2
A peeled part 9 is formed (see Fig. 5C), but this peeled part 9 is removed by forming the groove 6 (see Fig. 5C).
.

Thereafter, a weld bead 5 is formed on the groove 6 in the same manner, and then the weld bead 5 is finished by planing, thereby completing the mold of this invention (see FIGS. 5 d and e).

As mentioned above, in the continuous casting mold of this invention,
The inner surface of the lower half of the mold body, which is made of copper or a tempered alloy, is composed of an electrodeposited coating layer of nickel or nickel-based alloy that has a high melting point, excellent heat resistance, and is hardly scraped off by the solidified shell. Therefore, there is no risk of significant wear and tear on the inside of the mold due to the solidified shell, while the mold body 1
The inner surface of the upper half is made of copper or copper-based alloy, which has high thermal conductivity and therefore has a high heat removal effect, so it has excellent effects that can be used in practice for a long time, such as no mold inner surface cracking. It has the following.

[Brief explanation of drawings]

Fig. 1 is a vertical sectional view of a half part of a conventional mold, Fig. 2 is a longitudinal sectional front view of a half part of a mold of this invention, and Fig. 3 a''-'e is a longitudinal sectional front view of a main part showing the manufacturing process of a mold of this invention. Figure 4 is an enlarged longitudinal sectional view of the main part of Fig. 3, and Fig. 5C is a longitudinal sectional front view of the main part showing another manufacturing mode. , 1a...
...Inner surface of upper half, 2...Covering layer, 2a...Inner surface of curved coating layer, 4...Scratched portion, 5...Weld bead, 6.Curve... Bevel, 8...Tapered part.

Claims (1)

[Scope of utility model registration request] A wear-preventing coating layer of nickel or nickel-based alloy is electrodeposited on the inside of the lower half of the copper or copper-based alloy mold body to form the inner surface of the lower half that is continuous with the inner surface of the upper half. A continuous casting mold characterized in that the boundary between the inner surface of the upper half of the waist and the inner surface of the lower half of the waist are integrated by welding.