JPS5953142B2 - Continuous casting mold - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a continuous casting mold, and an object of the present invention is to provide a durable continuous casting mold that prevents cracks that are likely to occur in the upper part of the mold. .

Molds for continuous casting (hereinafter referred to as molds) include assembly molds for large castings and tube molds for small castings, but due to their characteristics, they are made of metal with good thermal conductivity, and they are made of metal with good thermal conductivity. The structure is such that the heat is cooled through the metal walls.

That is, since the mold material must be a metal with good thermal conductivity, copper is generally used in most cases.

However, a copper mold has the drawback that the inner wall is scraped when molten steel passes through it, and the copper material penetrates into the surface of the cast steel ingot, significantly degrading the quality of the steel ingot.

Various inventions have been made in the past as countermeasures against this problem.

The main one is to protect the inner surface of the mold with other metals.

For example, Japanese Patent Publication No. 46-37226 discloses that molybdenum and zirconium oxides are coated on the inner surface of a mold, that is, on the surface that contacts molten steel.

Further, Japanese Patent Publication No. 48-28255 discloses applying nickel plating to the inner surface of the mold.

Furthermore, Japanese Patent Application Laid-Open No. 49-83620 proposes to use nickel, chromium, molybutin, or stainless steel for the inner surface of the mold.

However, among these known examples, those using molybdenum can only be lined by plating or thermal spraying, so the metallurgical bond with the mold is weak, and zirconium oxide can only be lined by thermal spraying. Since it cannot be soaked, it also has a weak metallurgical bond similar to the above-mentioned molybdenum, and both have problems with durability.

Further, in the case of stainless steel, since its thermal conductivity is low, it impedes the thermal conductivity required for the molding material, which is undesirable.

Regarding chromium, plating is the only way to form a layer on the inner surface of the mold, and the plating thickness is only 0.3r.
There is a problem with durability because it can only be made less than .

Therefore, nickel is currently used in large quantities.
Methods for coating the inner surface of the mold include explosive pressure plating, thermal spraying, and the like.

However, molds whose inner surfaces are coated with nickel tend to crack at the top during use.

The present invention was made with the aim of improving the above-mentioned drawbacks of conventional molds.
At least one of Nb and Ta, or further,
0.1 to 2.5 of at least one of Be and V
This continuous casting mold is characterized by being lined with a copper alloy containing a copper alloy in the range of It does not cause cracks and has improved durability.

The present invention will be explained in more detail below with reference to the drawings.

The mold is constructed with a metal wall 1 with cooling fluid passages 7.

The metal wall 1 is made of a metal material with good thermal conductivity, and a lining 2 made of a metal material with good wear resistance is provided on the inside thereof,
The two are metallurgically combined.

3 is a meniscus formed at the top of the mold when molten metal is poured into the mold.

4 is the molten metal and 5 is its solidified portion. Conventional lining 2
When nickel was used in the part, cracks were likely to occur in the upper part 6 of the mold, which is the part where the meniscus 3 contacts.

Instead, if a copper alloy containing at least one of Ti, Zr, Nb, and Ta or at least one of Be and (2) is used in the range of 0.1 to 2.5%, cracking will be prevented. It turns out that this does not occur.

In this case, if the ratio of trace elements added to copper is too small, it will be meaningless, and as the amount increases, the thermal conductivity will deteriorate and it will be disadvantageous in terms of cost, so 0.1
A range of 2.5% to 2.5% is preferred.

Furthermore, if the entire mold is made from such a copper alloy, the thermal conductivity will decrease and it will be disadvantageous in terms of cost, so it is more advantageous to make a mold by press-welding the thin plate to the inside of a normal copper material. .

Among the additive elements, Ti, Zr, Nb, and Ta act to fix impurities (for example, S, etc.) in the steel, reduce crystal grain size, and improve physical properties.

Although any element may be used, it is more advantageous to use an element with a small atomic number when considering cost, thermal conductivity, physical properties, etc.

In addition, Be and V tend to increase corrosion resistance in the atmosphere under the conditions of use as a mold, and Ti, Zr,
It is even more effective when used together with Nb and Ta.

Although the present invention may be applied to the entire mold, since its purpose is to prevent the occurrence of cracks in the part of the inner wall 6 where the meniscus 3 is in contact, it is applied only to this part, and to the lower part of the inner wall. The portions may also be lined with other metals, such as nickel.

Furthermore, as a method for forming the lining in the present invention, an explosive crimping method is often used, but a build-up method, a rolling method, etc. may also be used.

Example 1 Copper plate 2 with a thickness of 60 mm, a width of 750 mm, and a length of 860 mm
One copper alloy plate (6 x 780 x 0 blades) having the composition shown in Table 1 was explosively bonded to each of the sheets to create two short sides for an assembly mold.

This was combined with a normal nickel coated mold (two long sides) to create an assembly mold.

As a result of continuous casting of steel for steel plates using this mold, 3
At 0.00 charge, cracks occurred in the nickel-coated mold, but no cracks occurred in any of the molds according to the present invention.

Example 2 In the same manner as in Example 1, a metal plate having the composition shown in Table 2 was attached to the inner surface of the short side of the mold, and a test was conducted. As a result, the nickel-coated mold cracked after 300 charges, whereas the present case The mold according to the invention is not subject to any force that may cause cracking.

[Brief explanation of drawings]

The figure is a sectional view showing the mode of use of the mold of the present invention. 1...Metal wall, 2...Inner lining, 3...
... Mechanicus, 4... Molten metal, 5...
... Solidified part, 6 ... Upper part of mold inner wall,
7... Cooling fluid passage.

Claims (1)

[Claims] l Continuous casting characterized by being lined with a copper alloy containing at least one of Ti, Zr, Nb, and Ta in a range of 0.1 to 2.5%. mold for At least one of 2Ti, Zr, Nb, and Ta
1. A mold for continuous casting, characterized in that it is lined with a copper alloy containing at least one of seeds, Be, and (2) in a range of 0.1 to 2.5%.