JP3464841B2 - Method for forming molten layer of sprayed metal on copper base material - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a molten layer of a sprayed metal on a copper base material, and more particularly to a copper mold for continuous casting of steel, which has excellent heat resistance and wear resistance. The present invention relates to a method for melt coating.

[0002]

2. Description of the Related Art Copper and copper alloys, which have good thermal conductivity, are generally used in continuous casting molds for steel, but the molten metal to be poured is extremely high in temperature and rubbed by the solidification shell, so Heavy wear and damage.

To solve this problem, conventionally, chrome plating,
It is dealt with by surface treatment such as nickel-iron alloy plating.
However, plating is not sufficient in heat resistance and abrasion resistance, and also has a problem of peeling during use.

[0004]

SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to provide a new method capable of fusion-welding a thermal spraying alloy having excellent heat resistance and wear resistance to a copper base material. is there.

[0005]

The first constitution of the method of the present invention made for the purpose of solving the above-mentioned problems is to provide a copper base material with a sprayed metal which is melted at a temperature not higher than the melting temperature of the base material. when forming a molten layer, and characterized in that induction heating of the solution reflecting surface to the melting temperature of the sprayed metal with a temperature gradient of 5 to 30 ° C. / mm between the surface opposite to the spray coat surface of the base material To do.

A second constitution of the method of the present invention which can solve the above-mentioned problems is to form a molten layer of a sprayed metal which is melted at a temperature equal to or lower than the melting temperature of the copper base material, after 50~400μm coated metal coating that melts at a temperature above the melting temperature of the base material to the base material, the sprayed metal to the coating on the metal film, the surface opposite to the spray coat surface of the base material before the solution reflecting surface while forming a temperature gradient of 3 to 35 ° C. / mm between
It is characterized in that the induction heating to the melting temperature of the serial sprayed metal.

[0007] In the present invention, it is possible to use a self-fluxing alloy to the sprayed metal. Further, the metal coating of the present invention may be an iron-based, nickel-based, or cobalt-based magnetic metal film, and may be performed while correcting thermal strain.

[0008]

Operation [Temperature Gradient] In the present invention, heating and melting the sprayed surface while providing a temperature gradient to the sprayed surface and the back surface is an essential condition for not melting the copper base material.

When sprayed directly on the copper base material, the temperature gradient is 5
The range of -30 ° C / mm is preferably in the range of 3-35 ° C / mm when the copper base material is coated with a metal film having a melting temperature higher than that of the base material.

The difference in temperature gradient range between the case of direct thermal spraying and the case of providing an intermediate metal is that the intermediate metal is generally inferior to copper in thermal conductivity and a kind of heat insulating effect is generated in this part. This is because even if the temperature gradient is small, the sprayed metal can be heated and melted without melting the copper base material. On the other hand, even if the temperature gradient is large, the intermediate metal hinders heat conduction, so that the sprayed metal can be rapidly heated and melted.

If the temperature gradient is less than the lower limit, the copper base material may melt, which is not preferable. On the other hand, if the amount exceeds the upper limit, fusion failure is likely to occur in the molten layer of the sprayed alloy, and cracks are likely to occur in the cooling process after melting.

In carrying out the method of the present invention, various conditions for forming the above temperature gradient differ depending on the wall thickness of the object, etc., but in any case, if the temperature gradient having the above content is provided, the melting can be suitably performed. .

[Intermediate Metal Layer] As described above, the presence of the intermediate metal layer has the effect of widening the range of the temperature gradient, and the melting temperature is higher than that of the copper base metal. The effect of preventing melting of the base metal at the interface is obtained. Further, there is an advantage that a sprayed metal having almost no difference in melting temperature from the copper base metal can be used. Therefore, the selection range of the sprayed metal is expanded, and the sprayed metal having high heat resistance and abrasion resistance can be selected.

The thickness of the intermediate metal layer is preferably in the range of 50 to 400 μm. When the thickness exceeds 400 μm, peeling easily occurs at the interface of the copper base material, which is not preferable. On the other hand, if it is less than 50 μm, the above-mentioned effects are small.

For forming the intermediate metal layer, a usual film forming technique such as plating, pressure welding, and explosive deposition can be used. As a metal forming the intermediate layer, a metal having a higher melting temperature than at least a copper base material such as iron, nickel, cobalt and an alloy containing them as a main component, particularly a magnetic metal can be preferably used.
Especially, nickel or nickel alloy is easy to use.

Here, the magnetic metal is recommended as the metal of the intermediate layer. Even if the sprayed metal is a magnetic metal, it is not induction heated until it is melted. In the present invention, the sprayed metal is an induction heating of the base metal. This is because, when the intermediate metal layer is provided as the underlayer of the sprayed metal, it is a preferable condition that the magnetic metal is a magnetic metal that can improve the situation of induction heating.

[Heating Method] In the case of flame heating, there is a risk that the temperature of the entire copper base material rises, that is, the temperature gradient becomes too small and the copper base material melts. In addition, thermal strain also increases.

Therefore, as the heating means for realizing the temperature gradient of the present invention, an induction heating method capable of rapidly heating the inside by specifying the heating portion is essential. But,
A suitable temperature gradient can be obtained because of the large thickness of the target object, but if it is difficult to obtain the temperature on the high temperature side necessary for melting the sprayed layer, use flame heating, furnace heating or induction heating. By preheating the whole and then rapidly raising the temperature by induction heating, the preferred temperature gradient described above can be entirely raised to carry out the present invention.
The preferred frequency range for induction heating is 20-200 KHz.

[Sprayed Metal] The sprayed metal is basically excellent in heat resistance and abrasion resistance, and any material can be used as long as the melting temperature is equal to or lower than the melting temperature of the copper base material. Among them, a self-fluxing alloy is preferable. Most preferred. For those whose melting temperature is almost the same as that of the copper base material,
It is preferable to use it after providing an intermediate metal layer.

A preferred component composition is a nickel group or a cobalt group, and in addition to boron and silicon, one or more elements for improving heat resistance and wear resistance such as chromium, molybdenum, and tungsten, and a slight amount of carbon. Accordingly, cobalt is added to the nickel group and nickel is added to the cobalt group.

If necessary, chromium may be added to the above gold component.
Various carbides such as tungsten and titanium can be added.

[Strain correction] The heating performed with a temperature gradient and the subsequent cooling in the method of the present invention tend to cause more remarkable thermal strain than ordinary heating / cooling. Therefore, when carrying out the method of the present invention, it is desirable to perform heating and cooling while correcting the shape of the object. The above correction involves engaging a machine / jig with an object,
It can be carried out by restraining it so as not to generate thermal strain, or by applying a displacement or load in the direction opposite to the thermal strain.

[0023]

The present invention will be described with reference to examples.

Example 1 Copper base material: 20 (thickness) x 50 (width) x 200 (length) Unit mm Thermal spray material: Self-fluxing alloy (JISMSFNi4) Unit: wt% Cr 16% (12 to 17) Fe 2.5% (5% or less) Si 4% (3.5 to 5.0) C 0.5% B 4% (2.5 to 4.0) Ni balance Cu 3% (4% or less) Mo 3% (4% or less) Range Spray thickness: 1.0mm Temperature gradient: 10 ℃ / mm Frequency of 40KHz, output 40kw on the spray surface by the mode shown in Fig. 1.
At a high frequency, and the opposite surface is cooled by jetting cooling water to form a temperature gradient of 10 ℃ / mm, and the feed rate is 1mm / se.
The sprayed alloy was melted at 1040 to 1060 ° C while moving in the longitudinal direction at c. In this example, by applying tension in the longitudinal direction of the object, the strain is 0.1 m.
I was able to stay below m. In FIG. 1, 1 is a copper base material, 2 is a sprayed layer, 3 is a melted sprayed layer, 4 is an inductor, 5
Is a cooling jacket. <Results> The microstructure after melting of the sprayed layer was a dense structure with no pores. An alloy layer was formed at the interface with the base material.

Example 2 Copper base material: 20 (thickness) x 50 (width) x 200 (length)
Unit mm Base treatment (Ni intermediate layer): 100 μm thick Ni electroplating film spraying material: Self-fluxing alloy (JISMSFNi4) Spraying thickness: 0.5 mm Temperature gradient: 15 ° C / mm The sprayed surface has a frequency of 40 KHz according to the mode shown in Fig. 2. , Output 20kw
Heated with high frequency. In this example, since the intermediate metal layer was present, the temperature was raised at half the output as in Example 1.
On the other side, a temperature gradient of 15 ° C / mm was formed without cooling. The sprayed alloy was melted at 1040 to 1060 ° C while moving in the length direction at a feed rate of 1 mm / sec. In this embodiment,
By applying a three-point bending displacement in the opposite direction to the thermal strain with a steel jig, the same small strain as in Example 1 could be obtained. In FIG. 2, 1 is a copper base material, 2 is a thermal sprayed layer, 3 is a molten thermal sprayed layer, 4 is an inductor, 5 is a cooling jacket,
6 is a Ni plating layer. <Results> The microstructure after melting of the sprayed layer was a dense structure with no pores. An alloy layer was formed at the interface with the base material.

[0026]

As described above in detail, the present invention provides heat resistance,
It has a feature that a thermal sprayed alloy layer having excellent wear resistance can be fusion-welded to a copper base material in a metallurgical manner, and is particularly effective as a copper cooling member having excellent reliability and durability.

[Brief description of drawings]

FIG. 1 is a sectional view showing a main part of an embodiment of a first embodiment.

FIG. 2 is a sectional view showing a main part of an embodiment of Example 2;

[Explanation of symbols]

1 Copper base material 2 Sprayed layer 3 Molten sprayed layer 4 inductor 5 cooling jacket 6 Nickel plating layer

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP 54-28228 (JP, A) JP 58-136762 (JP, A) JP 2-80549 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) C23C 4/00-4/18 B22D 11/059 110

Claims (5)

(57) [Claims] 1. When forming a molten layer of a sprayed metal that melts at a temperature equal to or lower than the melting temperature of the base material on a copper base material, 5 to 30 ° C./mm between the surface opposite to the sprayed surface of the base material. A method for forming a molten layer of a sprayed metal on a copper base material, which comprises heating the sprayed surface to a melting temperature of the sprayed metal while forming a temperature gradient. 2. When forming a molten layer of a sprayed metal that melts at a temperature equal to or lower than the melting temperature of the base material on a copper base material, a metal that melts at a temperature exceeding the melting temperature of the base material is formed on the base material. after 50~400μm coated film, the sprayed metal to the coating on the metal film, 3 to 35 ° C. between the surface opposite to the spray coat surface of the base material
A method for forming a molten layer of a sprayed metal on a copper base material, which comprises heating the sprayed surface to a melting temperature of the sprayed metal while forming a temperature gradient of / mm. 3. The method for forming a molten layer of a sprayed metal on a copper base material according to claim 1, wherein the sprayed metal is a self-fluxing alloy. 4. The method for forming a molten layer of a sprayed metal on a copper base material according to claim 2, wherein the metal coating is an iron-based, nickel-based, or cobalt-based magnetic metal film. 5. A method for forming a molten layer of a sprayed metal on a copper base material, wherein the method according to claim 1 is carried out while correcting thermal strain.