JPH0627262Y2 - Sealing material for overlay welding - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention prevents flux and molten metal from flowing out of a predetermined range when a roll-shaped body such as a metal pipe is built up in the circumferential direction. The present invention relates to a sealing material for build-up welding.

[Prior Art] When forming a flange portion or repairing a holed portion in a steel pipe, an iron pipe or the like, overlay welding is performed in the circumferential direction of a roll-shaped body. This build-up welding is carried out by pouring the flux in a molten state (melting it in place) while slowly rotating the roll-shaped body. This is done while winding tape-shaped or round or square string packing around the location.

Conventionally, asbestos has been used as this kind of packing. Asbestos also has resistance to molten iron, so it retained its shape and effectively fulfilled its purpose.
However, the use of asbestos has recently been banned from the viewpoint of occupational health, and the use of silica-based fibers or ceramic (aluminosilicate) fibers is now being researched as a substitute.

[Problems to be solved by the invention] However, since these fibers react with or weld to the molten metal, they are eroded when they come into contact with flux, resulting in a bad finish shape and time-consuming peeling. .

In order to achieve the above object, it is required to have heat resistance up to the temperature of the flux, be non-reactive with the flux, and be inexpensive.

[Means for Solving the Problems] In view of the current situation as described above, the present inventor has completed the sealing material for overlay welding of the present invention as a result of earnest research.
The feature is that the surface of the core material made of an inorganic fiber is covered with an expanded graphite sheet and integrated by an adhesive or a fixture.

The characteristics of expanded graphite are that it does not react with molten steel, so that the finish is beautiful, the peeling work is easy, and the thermal conductivity is good and the flux is well cooled. However, there is some difficulty in strength. Therefore, in the present invention, an inorganic fiber yarn excellent in heat resistance and strength is used as a core material, and a surface of expanded graphite is coated on the surface and both are adhered with an adhesive or wrapped from the outside with a net or a thread. Together, they overcome these problems.

As the inorganic fibers, silica-based fibers, ceramic (aluminosilicate) fibers, aligned fibers such as glass fibers, spun yarn, and the like are used.

As the string-like body, a knitted, braided or twisted product of the above fibers can be used. Further, the fibers may be formed into a rod-like felt shape (nonwoven fabric shape).

Further, the word "string-like body" is used as a concept including not only a circle but also an elongated rectangle, a square, an ellipse, etc. as its cross-sectional shape. That is, it may be tape-shaped or ribbon-shaped.

On the other hand, expanded graphite is obtained by the following manufacturing method.

An intercalation compound is obtained by treating natural graphite, pyrolytic graphite, quiche graphite, or the like with sulfuric acid, sodium nitrate, potassium permanganate, bromine, halide, or the like. This intercalation compound refers to a crystalline compound in which another reactive substance penetrates between the layers of the graphite layered structure, has a bond with the carbon plane, and maintains the carbon layered structure. When this is heat-treated at a high temperature, the intercalation compound generates gas, whereby the graphite layers are expanded. Usually 1 in the direction perpendicular to the carbon plane
Expand about 0 times. This expanded graphite is expanded graphite.

This expanded graphite may be mixed with a synthetic resin such as cellulose acetate or phenol resin as a binder. Also,
A mixture of graphite oxide may be used. Graphite oxide, which is also called graphitic acid, has a structure in which oxygen or the like is covalently bonded to the bonding ring plane of carbon.

After all, the expanded graphite referred to in the present invention only needs to contain the expanded graphite described above as the main component, and it is free to mix other materials.

In addition to the general properties that the expanded graphite has high heat resistance and light weight, it is easily deformed and has a large restoring force.
There are advantages such as good adhesion, and it can be said that the conditions as a packing material are suitably satisfied.

The sheet-like shape means a shape obtained by thinly molding the above-mentioned expanded graphite to a thickness of about 0.2 to 0.6 mm. Of course, the thickness is not limited to this, but if it is 0.2 mm or less, it is difficult to mold it into a sheet, and if it is 0.6 mm or more, the flexibility of the sealing material is reduced.

The term "coating" refers to covering the core material, which usually covers the entire core, but may cover a part. That is, it is possible to cover only the portion where the flux contacts.

The adhesive may be a usual one as long as it can bond the expanded graphite and the inorganic fiber.

The fixture is a fixture for fixing the expanded graphite sheet so as not to separate from the core material of the inorganic fiber, and a mesh or the like having high heat resistance such as stainless steel is preferable. That is, the net covers the periphery.

Further, a linear body may be wound instead of the net.

Further, a metal leaf spring-shaped holding device may be manufactured, sheet-shaped expanded graphite may be adhered to the outer surface of the holding device, and the holding device may be held by a core member like a clip.

[Embodiment] Next, the present invention will be described in detail based on an embodiment shown in the drawings.

FIG. 1 is a perspective view showing an example of the sealing material 1 of the present invention. In this example, an expanded graphite sheet 4 is provided around a core material 3 in which eight filaments 2 made of aluminosilicate fiber are knitted.
Is wound, and the periphery thereof is fixed with a stainless wire mesh 5. As a method of fixing with a wire net, the wound contact portion may be welded after winding, or a braiding method may be used. Further, instead of such a fixing tool, a commercially available adhesive such as isoprene, neoprene, or acrylic is used for the core material 3.
The expanded graphite sheet may be fixed. When the sheet-shaped expanded graphite is wound around the core material 3, it may be wound in a single layer, but it is preferably wound plural times.

In this example, as the expanded graphite sheet, an SG sheet (manufactured by Sumitomo Metal Industries, Ltd.) having a thickness of 0.4 mm was used.
The diameter after coating with wire mesh was about 5.0 mm.

FIG. 2 shows that the core material 3 formed by forming the felt-like inorganic fibers into a tape shape is covered with expanded graphite 4 (using the same material as described above), and stainless steel is applied from the periphery. The wire 6 is wound around and fixed.

FIG. 3 is a perspective view showing a usage state of the sealing material 1 shown in FIG. Two sealing materials 1 are wound around the steel pipe 7, and the groove 8 formed between them is filled with the steel by rotating the steel pipe 7 with the welding rod 9. Then, the collar is formed, but if the height is not enough for one rotation,
The depth of the groove may be increased by rotating the sealing material 1 a plurality of times by rotating it a plurality of times. There is also a method of deepening while filling.

FIG. 4 shows that the sealing material 1 is doubled by rotating the steel pipe 7. The lower part of the molten steel is already cooled and solidified.

In the experiments shown in FIGS. 3 and 4, the cooling was fast and the peeling after cooling was superior to the conventional one.

[Effect of the Invention] The present invention described in detail above has the following great advantages.

Peeling after welding is much easier than conventional products.

Since it is not eroded by molten steel or the like, the surface of the formed collar portion is smoother than that of the conventional product. Therefore, post-processing such as sanding becomes easy.

No work hygiene problems occur.

It is cheap.

Since the sealing material itself is not deformed or damaged by welding, it can be used repeatedly.

Since the expanded graphite has a high thermal conductivity, the inner flux is cooled in a single hour, resulting in good work efficiency.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of the sealing material of the present invention, FIG. 2 is a perspective view showing another example, FIG. 3 is a perspective view showing a usage state of the example shown in FIG. 1, and FIG. FIG. 4 is a partial sectional view of FIG. 3. 1 ... Sealing Material 2 ... Filament 3 ... Core Material 4 ... Expanded Graphite 5 ... Net 6 ... Wire 7 ... Steel Pipe 8 ... Groove 9 ... Welding Rod

Front page continued (72) Inventor Shizuo Kishino 3 Hikari, Kashima-cho, Kashima-gun, Ibaraki Myoko Naka Mining Co., Ltd. Business

Claims (1)

[Scope of utility model registration request] 1. A sealing material for build-up welding in which the surface of an inorganic fiber core material is covered with an expanded graphite sheet and integrated by an adhesive or a fixture.