JPS5939505B2 - Tuyere surface treatment method - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for surface treatment of tuyeres.

Tuyeres are usually made of copper or copper alloy for their cooling properties, and the surfaces (all internal and external surfaces) are coated with various heat-resistant and abrasion-resistant materials to prevent damage, but as mentioned above, the main body Since it is made of copper or copper alloy, its adhesion is low when thermal spraying is used, so most of the materials were based on plating.
Disadvantages include that the coating material was limited to materials that could be plated and that the coating process took a long time.

The present invention aims to provide a surface treatment method for a tuyere that eliminates the above-mentioned drawbacks, and its gist is to form a sprayed layer made of a durable material on the inner and outer surfaces of a tuyere body made of copper or copper alloy, Next, the entire outer peripheral surface of the sprayed layer is covered with a thin plate material in an airtight vacuum, and then hot isostatic pressure treatment is performed.

Note that hot isostatic pressure processing is a method of diffusion bonding by applying pressure from the entire circumference of the object to be processed under high temperature using argon gas, nitrogen gas, etc. as a pressure medium. As a pretreatment, it is necessary to cover the thin plate material in an airtight vacuum, that is, to make it airtight from the outside and without air inside the thin plate material.

Here, the term "sprayed layer made of durable material" refers to the heat resistance, abrasion resistance, corrosion resistance, etc. required to increase the durability of the tuyere, and includes various materials such as nickel or its alloys, stainless steel, etc. materials are used.

In addition, the thin plate material may be made of durable material similar to thermal sprayed material, or
Instead, there are cases in which a material with sufficient quality is simply used to perform airtight vacuum treatment on the sprayed layer; in the former case, the obtained tuyere is used with the thin plate material attached, and in the latter case, In some cases, only the thin plate material is removed by grinding, melting, or other means after hot isostatic pressing. Therefore, the material for the sprayed layer should always be of a type that diffusely bonds with the material of the tuyere body, but in the case of thin plate materials, if the thin plate is used as a final product, the material for the sprayed layer should be different from the material of the sprayed layer. It must be a material that forms a diffusion bond, but if it is to be removed at the final stage, either type of diffusion bond between the sprayed layer and the thermal spray layer may be used; rather, it is preferable to use a material that does not form a diffusion bond when considering subsequent removal. . In the method of the present invention, a sprayed layer made of a material having desired properties such as heat resistance is formed to a certain thickness on the inner and outer surfaces of the tuyere body, which is usually obtained as a cast product made of copper or copper alloy and has cooling water flow holes inside. form.

Since the tuyere body is made of copper or a copper alloy, the thermally sprayed layer does not bond firmly to the tuyere body, but the purpose is still achieved by forming the thermally sprayed layer there. Next, the entire outer peripheral surface of the sprayed layer is sealed with a thin plate material by electron beam welding or other means to create the airtight vacuum state as described above.

During this airtight vacuum treatment, the cooling water supply hole and the cooling water outlet opened in the wing body should not be blocked.

After that, it is charged into a hot isostatic pressurizing furnace and subjected to high temperature and high pressure treatment, and the cavities and other defects existing inside the tuyere body, which is a cast product, are compressed and the quality is improved, and the sprayed layer is removed. It is strongly sintered by itself, and is also diffusion-bonded to the tuyere body to form a strong bond. As mentioned above, the thin plate material may or may not be diffusion bonded to the sprayed layer depending on the selection of the material. In this case, the cooling water circulation holes opened inside the tuyere body are communicated with the outside through the cooling water supply hole and the cooling water outlet, so a hot isostatic pressurization method that applies pressure from all around the tuyere is used. The method of invention will never fail. When hot isostatic pressing is performed in the method of the present invention, the temperature is usually 800 to 1000°C and the pressure is 10°C, although it depends on the combination of the sprayed layer and the thin plate material.
The treatment shall be carried out at a pressure of 0 to 400 atmospheres.

As described above, according to the method of the present invention, it is possible to achieve the desired thickness on the inner and outer surfaces of the tuyere body, where it is difficult for the thermal spray material to adhere firmly because it is manufactured from copper or copper alloy, which has good thermal conductivity. In other words, the thermal sprayed layer formed first may have a sufficient thickness because the bond between particles within the sprayed layer and the degree of adhesion to the tuyere body may be small. This is possible, and the strength of the sprayed layer itself and the strength of the bond with the tuyere body are increased by subsequent hot isostatic pressure treatment.

Therefore, a wide variety of thermal spray materials can be selected as long as they form a diffusion bond with the tuyere body, so it can also be applied to various composite materials (for example, materials mixed with ceramics, etc.). It is possible, and in the method of using a thin plate material attached to the final product, it is possible to coat the surface with a wider variety of materials by combining the thermal spray material and the material of the thin plate. The method of the present invention also has the effect of improving the quality of the tuyere body, which is usually a cast product.

Claims (1)

[Claims] 1. A thermally sprayed layer made of a durable material is formed on the inner and outer surfaces of the tuyere body made of copper or copper alloy, and then the entire outer peripheral surface of the thermally sprayed layer is covered with a thin plate material in an airtight vacuum, and then hot isostatic A tuyere surface treatment method characterized by applying pressure treatment.