JPH07106457B2 - Method of connecting corrosion-resistant layer-coated metal bodies - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for connecting metal bodies coated with a corrosion resistant layer.

[Conventional technology]

Corrosion-resistant layer-coated metal bodies that are formed by coating the surface layer of the base metal with a corrosion-resistant metal layer, such as centrifugal force cast steel pipes whose surface is coated with stainless steel, are generally used for building pillars, etc. Is often used in. The reason why it is often used is that the corrosion-resistant layer-coated metal body is comprehensively excellent in terms of its mechanical properties, appearance and cost.

When a long length of the corrosion-resistant layer-coated metal body is required, the corrosion-resistant layer-coated metal bodies are arranged so that their ends are butted, and the butted portions are fusion-welded to connect the corrosion-resistant layer-coated metal bodies. is doing. Then, in the connection, arc welding such as tungsten inert gas arc welding is usually used.

Further, the arc welding is carried out under such a condition that the depth of the molten portion generated by the welding extends not only to the portion of the corrosion-resistant metal layer but also to the portion of the base metal.
This is because the required strength cannot be obtained at all even if only the portion of the corrosion resistant metal layer is fusion bonded.

[Problems to be Solved by the Invention]

Thus, when the corrosion-resistant layer-covered metal body is connected, the welded portion, which is the connection portion, is in a fusion-welded state over both the corrosion-resistant metal layer and the base metal, and therefore, between them. There is a problem that an electrochemical reaction occurs and electrolytic corrosion is generated based on the reaction, so that the appearance of the connected corrosion-resistant layer-coated metal body is impaired.

The present invention has been made in view of the above circumstances, and a method of connecting a corrosion-resistant layer-coated metal body capable of obtaining a connecting portion having a necessary strength and suppressing the occurrence of the electrolytic corrosion to solve the above problems. It is intended to be provided.

[Means for Solving the Problems]

The first characteristic configuration of the method for connecting corrosion-resistant layer-coated metal bodies according to the present invention is a state in which the edges of the corrosion-resistant layer-coated metal body in which the surface layer of the base metal is coated with the corrosion-resistant metal layer are abutted against each other. A method of connecting the corrosion-resistant layer-coated metal body by fusion-welding the butted portion, wherein the corrosion-resistant metal layer is removed from the butted portion of the corrosion-resistant layer-coated metal body, and remains. A step of fusion-bonding the base metal, a step of burying another corrosion-resistant metal layer at the abutting portion of the corrosion-resistant layer-coated metal body from which the corrosion-resistant metal layer has been removed, Including a step of fusion-bonding a joint between a metal layer and a corrosion-resistant metal layer originally coated on the surface layer of the base metal, in fusion-bonding the joint, the base materials of the both corrosion-resistant metal layers Prevents fusion to metal In order, the base material in advance to form a recess in the surface layer of the metal, and, in that you place the insert material in advance in the recess.

In addition, the second method of connecting the corrosion-resistant layer-covered metal body according to the present invention
The characteristic configuration of (1) is that a brazing material layer is attached in advance to the surface of the corrosion-resistant metal layer that is arranged so as to be buried, on the side of the base metal.

[Work]

When the corrosion-resistant layer-coated metal bodies are connected by the method of the present invention having the first characteristic configuration, the base metal metals are fusion-welded together and both the corrosion-resistant metal layers are fusion-welded together,
The required strength can be obtained at the joint portion of the joined corrosion-resistant layer-coated metal bodies.

Moreover, due to the presence of the recess formed in the surface layer of the base metal and the insert material previously arranged therein, both the corrosion-resistant metal layer and the base metal are fused at the time of welding the joint. Will be prevented. As a result, the occurrence of an electrochemical reaction between the two is suppressed, and the occurrence of electrolytic corrosion based on the reaction is also suppressed. Further, the corrosion-resistant layer-coated metal body is formed by the method of the present invention having the second characteristic configuration. When connecting, the brazing material layer previously attached to the surface of the base metal metal side of the corrosion-resistant metal layer is melted by the heat generated by the welding at the time of welding the joint portion, and thereby the buried portion is arranged. A brazing state is formed between the corrosion resistant metal layer and the base metal.

〔The invention's effect〕

According to the method of the present invention having the first characteristic configuration, as described above, the necessary strength can be obtained at the connecting portion of the corrosion-resistant layer-covered metal body, and the electric power at the joint portion between the corrosion-resistant metal layers can be obtained. The occurrence of corrosion is suppressed, and thus the above-mentioned conventional problems are solved.

Further, according to the method of the present invention having the second characteristic configuration, the corrosion-resistant metal layer and the base metal, which are disposed in a buried state, are in a brazing state. The strength of the connecting portion is further improved as a whole.

〔Example〕

Hereinafter, a method of connecting corrosion-resistant layer-coated metal bodies according to the present invention will be described with reference to the drawings.

4 (A), (B), (C), (D), (E),
(F) is a corrosion-resistant layer-covered metal body (1
It is a schematic explanatory drawing which shows the manufacturing method of 0) in order of process.

As shown in FIG. 4 (A), a centrifugal cast steel pipe (11) serving as a base metal, and a stainless steel plate (12) serving as a corrosion-resistant metal layer to cover the outer peripheral surface of the centrifugal cast steel pipe (11). ) And are first prepared. The centrifugal cast steel pipe (11) is subjected to shot blasting to remove scale from the surface of the centrifugal cast steel pipe (11).

Next, the stainless steel plate (12) is bent and wound around the centrifugal cast steel pipe (11), and in the wound state, the portion where the butted end faces of the stainless steel plate (12) face each other is made of tungsten inert gas. Arc-welded and thus the centrifugal cast steel pipe (11) is coated with a stainless steel plate (12) on the outer periphery as shown in FIGS. 4 (B) and 4 (C) (both figures show the same process). The material (14) of the two-layer metal combination (13) thus arranged is obtained.

Next, the material (14) of the two-layer metal combination (13) is charged into the vacuum chamber of the electron beam welding machine, and both edges (14a) of the material (14) are melted in a vacuum. Circumferential electron beam welding is performed under such conditions that the depth reaches the centrifugal force cast steel pipe (11). As a result, the gap between the centrifugal cast steel pipe (11) and the stainless steel plate (12) is sealed under reduced pressure, and both of them (11) and (12) are as shown in FIG. 4 (D). A two-layer metal combination (13) is obtained which is integrated via an electron beam weld (13a).

Next, the two-layer metal combination (13) is subjected to hot isostatic pressing using a hot isostatic pressing device. Specifically, for the two-layer metal combination (13), hot isostatic pressing was performed under the conditions of treatment temperature: 1200 ° C., treatment pressure: 1000 kg / cm ² , atmosphere gas: argon gas, treatment time: 2 hr. Apply processing. As a result, as shown in FIG. 4 (E), the two-layer metal combination (13) was compressed, and the stainless steel plate (12) conformed to the surface shape of the centrifugal cast steel pipe (11). A hot isostatic pressing product (15) is obtained. Although the processing temperature of the hot isostatic pressing was 1200 ° C in the above example, the hot isostatic pressing product (15) can be effectively obtained even when the processing temperature is 930 ° C. When the centrifugal cast steel pipe (11) is carbon steel, the cast steel pipe (11) after casting and cooling is heated to 930 ° C., held for a predetermined time, and then air-cooled to perform a heat treatment to give a predetermined strength. This heat treatment is the same as the hot isostatic pressing treatment.
It is also used by treating at ° C, and it can be omitted.

Next, the existing portion of the electron beam welded portion (13a) in the hot isostatic pressing product (15) is cut and removed, and a fourth
A metal body (10) coated with a corrosion resistant layer as shown in FIG.

The corrosion-resistant layer-coated metal body (10) thus obtained has the surface of the centrifugal cast steel pipe (11) on which the casting surface pattern is transferred,
Has excellent designability.

When such a corrosion-resistant layer-coated metal body (10) is used, if its length is insufficient, as shown in FIG. 2, the corrosion-resistant layer-coated metal body (10) is brought into a state where its ends are butted against each other. And the butted portion (10a) is fusion-welded to connect the corrosion-resistant layer-covered metal body (10). And
Arc welding such as tungsten inert gas arc welding is usually used for the connection.

When connecting the metal body (10) coated with a corrosion resistant layer, the metal body (10) coated with a corrosion resistant layer is previously shown in FIG. 1 (A).
Pre-processing as shown in. That is, as one of the pre-processing, a corrosion-resistant metal layer (12) having a predetermined width from the abutting part (10a) of the corrosion-resistant layer-covered metal body (10) and another corrosion-resistant metal layer (12) are buried and arranged. It is removed (for example, removed by grinding) over the entire circumference as a space when performing. Further, as another one of the pre-processing, the remaining portion of the butted portion (10a), in other words, the centrifugal cast steel pipe (1) at the butted portion (10a).
In the part of 1), that is, the part of the base metal (11), the base metal (1
1) Form a groove (11b) for welding the two together. Also,
As another one of the pre-processing, a joint portion (12) of both corrosion-resistant metal layers (12) described later is formed on the surface layer of the base metal (11).
When welding a), a recess (11a) is formed in advance in both corrosion resistant metal layers (12) to prevent fusion with the base metal (11).

Then, as shown in FIG. 1 (B), after the base metal (11) on which the groove (11b) for welding is previously formed is joined by arc welding, as shown in FIG. 1 (C). As shown, an insert material (20) for preventing fusion of both the corrosion-resistant metal layers (12) to the base metal (11) in the recess (11a) in the surface layer of the base metal (11). After arranging, the corrosion resistant metal layer (12) made of stainless steel is removed, and a corrosion resistant metal layer (12) made of another stainless steel is buried in the part, and the corrosion resistance of the buried structure is set. A joint (12a) between the metal layer (12) and the corrosion-resistant metal layer (12) originally coated on the surface layer of the base metal (11) is arc-welded.

Thus, when the corrosion-resistant layer-coated metal bodies (10) are connected, the base metal (11) is fusion-welded with each other and both the corrosion-resistant metal layers (12) are fusion-welded, so that the connected corrosion-resistant A necessary strength can be obtained at the connecting portion of the layer-covered metal body (10). Moreover, the concave portion (11a) formed in the surface layer of the base metal (11) and the insert material (2) previously arranged therein.
The presence of 0) prevents fusion of the corrosion-resistant metal layer (12) and the base metal (11) during welding of the joint (12a).

[Another embodiment]

As shown in FIG. 3, an embodiment in which a brazing filler metal layer (30) is attached in advance to the surface corresponding to the base metal (11) side of the corrosion-resistant metal layer (12) arranged in the above-mentioned manner is also considered. To be

In such an embodiment, the corrosion-resistant layer-coated metal body (10)
When connecting the base metal (11) of the corrosion-resistant metal layer (12)
The brazing filler metal layer (30) previously attached to the side surface is melted by the heat generated by the welding at the time of welding the joint portion (12a), and based on that, the corrosion-resistant metal layer (12) arranged in a complementary manner. A brazing state is formed between the base metal and the base metal (11). When the brazing material layer (30) is hard brazing and cannot be melted by the heat of the welding, it is heated by another means such as a burner to melt it.

Further, the method of the present invention is a corrosion-resistant layer-coated metal body other than the above-described corrosion-resistant layer-coated metal body (10), for example, a corrosion-resistant layer coating obtained by shrink-fitting a stainless steel pipe around a centrifugally cast steel pipe to tightly integrate the two. It can also be applied to a metal body.

Further, the method of the present invention can be applied even if the corrosion-resistant layer-covered metal body has a flat plate shape.

In addition, the insert material (2
Depending on the situation, 0) may not need to be placed. The existence of the concave portion (11a) is sufficient for the above-mentioned operation.
This is because it may have an effect.

Needless to say, the materials of both layers of the corrosion-resistant layer-covered metal body may be other than those mentioned above.

It should be noted that although reference numerals are added to the claims for convenience of comparison with the drawings, the method of the present invention is not limited to the method shown in the accompanying drawings.

[Brief description of drawings]

1 (A), (B), and (C) are schematic explanatory views showing an embodiment of the method of the present invention in the order of steps, and FIG. 2 is a perspective view showing a connected state of the corrosion-resistant layer-coated metal body, and FIG. The figure is a cross-sectional view showing a corrosion-resistant layer-covered metal body connecting portion in another embodiment of the method of the present invention, and FIGS. 4 (A), (B), (C), (D), (E), (F).
[Fig. 3] is a schematic explanatory view showing, in the order of steps, a method for producing a corrosion-resistant layer-coated metal body connected by the method of the present invention. (10) …… Corrosion-resistant layer-covered metal body, (10a) …… Butt portion, (11) …… Base metal, (11a) …… Concave portion, (12)…
… Corrosion resistant metal layer, (12a) …… Joint part, (20) …… Insert material, (30) …… Brazed material layer.

Claims (2)

[Claims] 1. A corrosion-resistant metal layer (1) on a surface layer of a base metal (11).
The corrosion-resistant layer-covered metal body (10) coated with 2) is arranged in a state where the ends thereof are butted against each other, and the butted portions (10a) are fusion-welded to each other, whereby the corrosion-resistant layer-coated metal body (10) is obtained. A method for connecting the remaining base metal (11) with each other in a state where the corrosion resistant metal layer (12) is removed from the abutting part (10a) of the corrosion resistant layer-coated metal body (10). A step of contacting with each other, a step of burying another corrosion-resistant metal layer (12) in a butting portion (10a) of the corrosion-resistant layer-coated metal body (10) from which the corrosion-resistant metal layer (12) has been removed, A step of fusion-welding a joint portion (12a) between the corrosion-resistant metal layer (12) arranged to be buried and the corrosion-resistant metal layer (12) originally coated on the surface layer of the base metal (11), When fusion-bonding the joint part (12a), the base metal (11) of both the corrosion-resistant metal layers (12) is used. In order to prevent fusion to the base metal (11), a recess (11a) is formed in the surface layer of the base metal (11) in advance, and an insert material (20) is placed in the recess (11a) in advance. How to connect the body. 2. The corrosion resistant layer according to claim 1, wherein a brazing material layer (30) is previously attached to a surface of the corrosion resistant metal layer (12) which is arranged so as to be arranged on the side of the base metal (11). Method for connecting coated metal bodies.