KR20180120411A - Cladding pipe and method for manufacturing the same - Google Patents

Abstract

A clad pipe, joining both end units of a clad plate material to which a first plate having a first melting point and a second plate having a second melting point lower than the first melting point are bonded to each other, according to the present invention is characterized by having a first joint. The outer surface of the clad pipe is the first plate, the inner surface of the clad pipe is the second plate, and at least a part or all of the end units of the plate are melted and joined.

Description

[0001] CLADDING PIPE AND METHOD FOR MANUFACTURING THE SAME [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a clad pipe and a method of manufacturing the clad pipe. More particularly, the present invention relates to a clad pipe manufactured by assembling a clad plate with two or more plates having different melting points joined together, and a manufacturing method thereof.

Cladding is a method of bonding different metals to one side or both sides of a plate or a pipe, and can realize excellent durability, heat resistance, and corrosion resistance by joining other metals, and is widely used for plates, pipes, and containers.

Korean Patent No. 10-1353815 has proposed a clad steel plate made of stainless steel / aluminum / stainless steel, which is known to be mainly used in the manufacture of kitchen containers. However, it is not easy to produce a clad steel pipe in the form of a container formed by deep drawing. The reason is that aluminum is dissolved due to the high thermal conductivity (60%) of aluminum due to the high heat generated in high frequency welding, and the aluminum moves to the outside of the welded portion of the stainless steel, thereby causing interference with the welding. That is, fusion of stainless steel and aluminum does not occur. Therefore, when a clad steel pipe is manufactured by the above-described method, a space that does not fill with aluminum is formed around the inside of the intermediate aluminum and the clad steel pipe, so that the structural function of the clad steel pipe, such as the bonding strength, hardness, corrosion resistance, wear resistance, It does not have functionality. Also, since the aluminum is thickly inserted into the intermediate side base material, the manufacturing cost is high.

On the other hand, the piping steel pipe which has the fatal disadvantages of easily knocking is a problem that is caused by the aging corrosion corrosion water pipe in the domestic and foreign countries, have.

To solve this problem, the most widely used stainless steel plate for piping is 304 austenitic stainless steel plate and is made of 18 wt% nickel. Such stainless steel plate shows excellent corrosion resistance and processability and is excellent in welding. However, the austenitic stainless steel has a disadvantage of high price because it contains expensive nickel.

Further, research on the manufacturing method of a cylindrical pipe using a steel plate in which a heterogeneous plate material is not a single material but clad is not actively carried out, and its manufacture is not easy. This is because, when the cylindrical steel pipe is manufactured using the clad steel sheet, the bonded plates have different material properties and it is difficult to join due to the structure in which the side edges extending in the longitudinal direction are directly facing each other.

 Therefore, when the above-mentioned problems are taken into consideration, there is a problem in that it is not easy to produce a tube having excellent corrosion resistance, abrasion resistance, durability and the like at low cost when a clad steel pipe is manufactured using a clad plate material.

Korea Patent No. 1605248 Korean Patent Publication No. 1997-0073462 Japanese Registered Utility Model No. 3013825 Japanese Patent Application Laid-Open No. 2004-249367 Japanese Patent Laid-Open No. 1995-054367 Korean Patent Publication No. 2001-67599 Korean Patent No. 1535936 Korean Patent No. 377364

In order to solve the problems of the conventional art as described above, it is an object of the present invention to solve a problem of a bonding failure which appears when a cylindrical clad pipe is manufactured from a clad sheet material.

Accordingly, it is an object of the present invention to provide a cylindrical clad pipe excellent in various physical properties manufactured using a clad sheet material and having excellent bonding properties.

It is another object of the present invention to provide a method of manufacturing a clad pipe using a clad plate which can be easily manufactured at low cost by forming an adhesive layer between a thermal spray bonding layer and a non-thermal bonding layer.

Another object of the present invention is to provide a method of manufacturing a clad pipe capable of preventing oxidation when a clad steel pipe is manufactured by using a stainless steel clad plate in which a stainless steel plate is clad on a steel plate.

In order to solve the problem of the present invention, both ends of a first plate having a first melting point and a second plate having a second melting point lower than the first melting point are bonded to each other Wherein an outer surface of the clad pipe is the first plate, an inner surface of the clad pipe is the second plate, and at least a part or all of the end of the plate is melted A clad pipe having a bonded first joint is provided.

The cladding pipe may further include a second bonding portion between the both ends of the first plate, the first bonding portion being bonded with a growth material filling the gap between the both ends, And may have a lower or equal third melting point.

Further, the present invention provides a clad pipe in which the material of the first plate is steel and the material of the second plate is stainless steel.

The clad plate used in the clad pipe according to the present invention is characterized in that the first plate and the second plate are joined to each other by a thermal spray bonding layer formed by thermal spraying and a thermal spray bonding layer not depending on thermal spraying, The bonding layer is formed using a metal bonding or an organic adhesive.

The thermal spray bonding layer of the clad sheet used in the clad pipe is formed in the boundary region in the longitudinal direction in which the first and second plates are joined together and the thermal spray bonding layer is formed in the central region where the thermal spray bonding layer is not formed .

The clad pipe according to the present invention may further include a coating layer on its outer surface.

The first joint portion of the clad pipe according to the present invention may be formed by melting both ends of the second plate and a portion of both ends of the first plate.

The present invention also provides a method of manufacturing a clad sheet, comprising the steps of: supplying a clad sheet material having a first plate having a first melting point and a second plate having a second melting point lower than the first melting point; A forming step of forming an end portion in the longitudinal direction of the clad sheet material by forming the cylindrical open tube with the first plate material outside and the second plate material inside; And a first joining step of joining and joining the ends of the cylindrical open tube, wherein at least a part or all of the ends are melted and joined to each other.

The method of manufacturing a clad pipe may further include a second bonding step of growing and welding the gap between the end portions of the first plate.

In the method of manufacturing a clad pipe according to the present invention, the first bonding step may be to melt the end portion by high frequency induction heating. The high-frequency induction heating may internally heat the inside of the end by incorporating an Impeder core inside the cylindrical open tube.

In the method of manufacturing a clad pipe according to the present invention, the clad sheet material may include a thermal spray bonding layer in at least one region, or a thermal spray bonding layer in at least one region and a non-thermal bonding layer in another region. The cost bonding layer may be formed using an organic adhesive or metal.

In the clad pipe manufacturing method according to the present invention, the thermal spray bonding layer is formed in a boundary region in the longitudinal direction in which the first plate and the second plate are joined together, Lt; / RTI > region.

In the method of manufacturing a clad pipe according to the present invention, the first joining step may be carried out by injecting cooling water to the remaining portion except the joining portion of the cylindrical open tube end or filling the inside of the open tube with cooling water, The inside and outside of the open tube can be performed under an inert atmosphere or a reducing atmosphere.

In the clad pipe manufacturing method according to the present invention, the first plate may be a steel plate, and the second plate may be a stainless steel plate.

The clad pipe manufacturing method according to the present invention may further include a rolling step of pressing and flattening the bead of the joint portion generated after the first joining step.

According to the present invention, it is possible to prevent the alloying of a material having a high melting point and a material having a low melting point by melting and bonding the end portions of the plate material having low melting points at the time of manufacturing a clad pipe to which two materials having different physical properties are bonded, The bonding property of the steel pipe is very excellent.

Further, after joining both ends of the low melting point plate material, it is possible to weld the plate material at lower temperature than the melting point of the low melting point material between the both ends of the plate material having high melting point, This has a very good effect.

In addition, according to the present invention, the clad plate material having the organic adhesive (nonwoven fabric) layer is subjected to high-frequency welding to locally heat both ends of the open tube at the time of manufacturing the clad steel pipe, It is possible to manufacture a clad steel pipe in which the layer is not released and can be produced at a low cost while maintaining excellent bonding properties as compared with a clad steel pipe in which the entire bonding surface of the clad sheet material forms the thermal spray bonding layer, .

In addition, by using a clad plate material in which a stainless steel plate material is clad on a steel plate material according to an embodiment of the present invention, welding can be performed in a reducing atmosphere when producing a clad pipe, thereby preventing oxidation of stainless steel, .

FIG. 1 is an explanatory diagram illustrating a spraying step according to the present invention. FIG.
Fig. 2 is an explanatory diagram for explaining a lamination starting step according to the present invention.
3 is an explanatory diagram for explaining a connection step according to the present invention.
Fig. 4 is an explanatory view illustrating the rolling step according to the present invention. Fig.
5 is an explanatory view illustrating the surface modification step according to the present invention.
6 is a process diagram illustrating a method of manufacturing a cladding plate according to an embodiment of the present invention.
7 is a cross-sectional view of a cladding plate having a thermal spray bonding layer and a non-thermal bonding layer according to an embodiment of the present invention.
8 is a cross-sectional view of a cladding plate having a thermal spray bonding layer and a non-thermal bonding layer according to another embodiment of the present invention.
9 is a cross-sectional view of an embodiment of a clad pipe according to another aspect of the present invention.
10 is an explanatory view for explaining a manufacturing process of a clad pipe which is another aspect of the present invention.

Hereinafter, the present invention will be described in more detail as an embodiment.

It should be understood, however, that there is no intent to limit the scope of the present invention to the particular embodiments or examples disclosed, and that ordinary skill in the art, having the benefit of the teachings of the present invention, It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

A method of manufacturing a cladding sheet according to an aspect of the present invention includes a sheet material supplying step, a spraying step, a lamination starting step, a connecting step and a rolling step.

The sheet material feeding step according to the present invention refers to a step of conveying the first sheet material wound on the first roller and the second sheet material wound on the second roller for successively cladding. At this time, the materials of the first plate and the second plate to be bonded are not limited, but usually metals, ceramics, alloys and the like can be bonded.

FIG. 1 is an explanatory diagram illustrating a spraying step according to the present invention. FIG. The injecting step is carried out before the first plate 1 and the second plate 2 are joined to the first joint surface 1a of the first plate 1 and the second joint surface of the second plate 2 2a simultaneously or individually with droplets of the spraying bonding material in a predetermined region. At this time, one minute event or two or more minute events can be used. At this time, the bonding material to be sprayed is not limited as long as it is a material which can be sprayed. Generally, metals, ceramics, alloys, composites and the like can be used as the spraying material.

As the injection method, a known injection method can be used. For example, wire spraying, electric arc spraying, powder flame spraying, high velocity recycling process, arc plasma process, induction plasma spray, and the like can be selectively used.

The size and speed of the droplets to be sprayed can be varied by those skilled in the art depending on the type of the material to be bonded.

Fig. 2 is an explanatory diagram for explaining a lamination starting step according to the present invention. The lamination starting step is a step of splatting splats generated due to the collision of the spraying material droplets in a predetermined region on each of the joining face 1a of the first plate 1 and the joining face 2a of the second plate 2 And the first sprayed layer 3 and the second sprayed layer 4 are formed on the respective joint surfaces (FIG. 2A).

The droplets ejected on the respective bonding surfaces deform as they are collided with each other, deformed according to the surface shape of the bonding surface, or flattened to form a splat to be coated, another splat overlaps on each splat, And cooled to form a first sprayed layer 3 and a second sprayed layer 4, respectively.

The first sprayed layer 3 and the second sprayed layer 4 may be a single sprayed layer connected to each other from the start according to the spraying conditions, but for convenience sake, the first sprayed layer 3 is formed on the first jointed surface, And the second sprayed layer 4 when formed on the second joint surface.

When the droplets of the spraying bonding material are sprayed between the first and second plates, the first sprayed layer 3 and the second sprayed layer 2 are formed on the joint surface of the first plate 1 in accordance with the material and the spraying conditions The first sprayed layer 3 and the second sprayed layer 4 are connected to each other at first from the beginning, and the second sprayed layer 4 is laminated on the jointed surface (Fig. 2B) (Fig. 2C), but the present invention includes all of them.

The spray guns forming each sprayed layer may be the same or different, and the sprayed materials may be the same or different.

In order to prevent the oxidation of the bonding material during spraying, the thermal spray may be conducted in a vacuum or an inert atmosphere, or an inert gas may be used as the carrier gas.

As described above, in the laminating start step, the sprayed layer is formed in each predetermined region, and the other regions where the sprayed layer is not formed may be formed as void spaces or a cost sublayer.

The cost sublayer may be formed in another region where the sprayed layer is not formed on at least one of the first bonding face and the second bonding face before or during the injection step. If empty spaces are formed in other regions where no sprayed layer is formed, or if a cost layer is formed, economical efficiency can be secured by lowering the production cost by reducing the spraying material and the spraying device, have.

The cost sublayer is formed by using a material capable of joining the first and second plates in addition to using the sprayed material. For example, by applying an organic adhesive or a metallic material. Particularly, in the present invention, the step of forming the cost-quadruple layer may be performed through an organic adhesive application process and a drying process. The organic adhesive used in the step of forming the cost layer may vary depending on various factors such as the type and thickness of the plate, and the type of the organic adhesive is not limited, but may be an epoxy resin, an acrylic resin, an acrylic resin anaerobic Acrylic resin anaerobic, polyuretheane resin, polyvinyl chloride solvent type, cyanoacrylate, water based polymer-isocyanate, styrene- At least one selected from the group consisting of styrene-butadiene rubber, nitrile rubber, phenolic resin and polyimide hotmelt may be used.

3 is an explanatory diagram for explaining a connection step according to the present invention. The connecting step is a step of connecting the first sprayed layer 3 and the second sprayed layer 4 to each other. The first sprayed layer 3 formed on the first joint surface of the first plate 1 in the lamination start step, And the second sprayed layer 4 formed on the second joint surface of the second plate 2 are connected to each other.

Preferably, the connection of the two sprayed layers can be connected to each other while connecting the stacks of spatters by continuous spraying. As a result, the first sprayed layer and the second sprayed layer form a single sprayed bonding layer. In this case, the layers are not physically distinguished, but form one layer, the first sprayed layer is bonded to the first plate, the second sprayed layer is bonded to the second plate, The two sprayed layers are connected by the same spray so that the first plate and the second plate are joined to each other.

Fig. 4 is an explanatory view illustrating the rolling step according to the present invention. Fig. The rolling step is a step of pressurizing after the connecting step or at the same time as the connecting step and applying pressure to the inside from both sides of the first plate 1 and the second plate 2 to plasticize the joined body to further increase the bonding force (Fig. 4A).

The thermal spraying layer formed by the rolling by spraying maintains the oxidation stability and has a high adhesive strength between the first plate 1 and the second plate 2, as compared with the case where only the sprayed layer is formed.

The rolling step of passing the first plate 1 and the second plate 2 between one or more rolling rollers is performed at a point where the first plate 1 and the second plate 2 are inserted into the rolling roller 5 The droplet is injected in the use case 6, so that the formation and rolling of the spray bonding layer 7 and the non-bonding layer can be performed almost simultaneously (FIG. 4B).

Here, the cost yarn joining layer is generated at the same time as the rolling process, in which the four layers of the non-sprayed layer are formed by joining together. At this time, the rolling method is not limited to any one, and hot rolling or cold rolling may be selected and used depending on the time and material of the thermal spray bonding layer.

On the other hand, the surface modification step may further include a surface modification step of modifying the surfaces of the first plate and the second plate so as to enhance the bonding force to which the first sprayed layer and the second sprayed layer adhere to the first plate and the second plate.

5 is an explanatory view illustrating the surface modification step according to the present invention. The surface modification is carried out by forming separate spray coating layers 8 and 9 on the joint surfaces 1a and 2a of the first plate 1 and the second plate 2 before the above-described injection step. The bonding material capable of strengthening the bonding is melted and sprayed to form spray coating layers 8 and 9, and the spray coating layer becomes the bonding surfaces 3a and 4a of the respective material bodies. The spray coating layers 8 and 9 can be formed of the same material as that of the spray bonding layers 3 and 4 to be formed later or can be formed of other materials.

6 is a process diagram illustrating a method of manufacturing a cladding plate according to an embodiment of the present invention. According to this, the method for producing a cladding sheet includes a sheet material supplying step, a cost four-layer forming step, a spraying step, a lamination starting step, a connecting step and a rolling step.

The first sheet 1 wound on the first roller may comprise a surface treatment process 10 during sheet transfer for cladding. The surface treatment process may include a surface cleaning process 11 for forming surface irregularities (roughening) by a method such as sanding and polishing, and cleaning the oxidized surface.

In addition, the first plate 1 may be subjected to a step of forming a cost four-layered structure by forming all or a part of another region where no sprayed layer is formed before the spraying step 15 of the thermal spraying material. The cost layer may be formed using a material capable of bonding the first plate 1 and the second plate 2 in addition to using the sprayed material, for example, by applying a metal or an organic adhesive . In this embodiment, the step of forming the cost layer is performed through the organic adhesive applying step (12) and the drying step (13).

The step (12) of applying the adhesive to the first sheet material 1 for the formation of the cost layer can be carried out by applying a liquid adhesive to the roll and applying the adhesive to the roll. At this time, it is preferable that two or more rolls are brought into contact with each other and rotated at the same speed, so that the liquid adhesive is supplied to the uppermost roll by the at least one static pressure flat flow rate supply unit. When the adhesive is applied in such a manner, the adhesive can be uniformly distributed over the entire roll, and the adhesive is evenly distributed to the lowermost roll that contacts the first plate 1 and rotates to uniformly spread the adhesive in a predetermined region of the first plate 1 Can be applied. The first sheet material 1 to which the adhesive is uniformly applied can be moved to the drying furnace and can be subjected to the adhesive drying step (13).

The adhesive drying step (13) includes a step of evaporating and drying the vaporizable gas in the adhesive by a hot air drying method or the like in order to make the adhesive applied on the first plate (1) have a bonding point having the highest bonding force. In this case, the drying temperature may vary depending on the thickness and material of the first plate, and the traveling speed, but may be 200 to 250 ° C.

The amount of the organic adhesive used for the formation of the interlayer on the first plate may vary depending on various factors such as the type and thickness of the plate and the type of the organic adhesive is not limited to epoxy resin, Acrylic resin anaerobic, polyuretheane resin, polyvinyl chloride solvent type, α-Cyanoacrylate, water based polymer-isocyanate (water-based polymer-isocyanate) At least one selected from the group consisting of styrene-butadiene rubber, nitrile rubber, phenolic resin and polyimide hotmelt may be used.

It is preferred that the second plate 2 be subjected to a heating step 14 during which the first plate 1 forms (12, 13) a cost sublayer. This is because when the second plate material 2 and the first plate material 1 are bonded to each other, the adhesive applied to the first plate material easily penetrates and adheres to the fine gaps of the surface to which the second plate material is bonded, It is preferable to continuously and uniformly heat the adhesive to a temperature range similar to the adhesive drying temperature.

As described above, the first plate and the second plate which have undergone the above-described processes are provided with a jetting step (15) for jetting droplets of the thermal spraying material into a predetermined region (except for the cost four-layer formation region) A splicing start step of splitting the splits to form a sprayed layer, a splicing step of connecting the sprayed layers to each other to form a sprayed joint layer, and a rolling step of cladding the first and second plates by a rolling roller Thereby forming a cladding plate. In the rolling step, it can be considered that the thermal spray bonding layer and the non-thermal bonding layer are generated at the same time.

Since the cladding plate manufactured through the above process is in a heated state, the cladding plate is subjected to a cooling process 17 using water, followed by wind-drying the water 18, and the finished cladding plate can be wound into a coil 19 to be commercialized.

7 is a cross-sectional view of a cladding plate having a thermal spray bonding layer and a non-thermal bonding layer according to an embodiment of the present invention. According to this, the cladding plate includes the first plate 1, the second plate 2, the thermal spray bonding layer 50, and the thermal spray bonding layer 51, and the thermal spray bonding layer 50 includes the first plate 1, (Edge) in the longitudinal direction in which the first sheet member 1 and the second sheet member 2 are joined together, and a cost bonding layer 51 is formed in the central region (Fig. 7A).

In addition, a part of the adhesive of the non-oxidized joint layer 51 is moved by the rolling step, and the mixed joint layer 52 of the thermal spray bonded layer 50 and the non-oxidized joint layer 51 is generated (Fig. 7B).

On the other hand, unlike the present embodiment, the positions of the thermal spray bonding layer and the non-thermal bonding layer can be variously set according to the kind of the plate to be manufactured.

8 is a cross-sectional view of a cladding plate having a thermal spray bonding layer 50 and a non-thermal bonding layer 51 according to another embodiment of the present invention. The cladding plate includes both the thermal spray bonding layer 50 and the thermal spray bonding layer 51 and the thermal spray bonding layer 50 is formed by laminating the first plate 1 and the second plate 1 together, And the non-bonding layer 51 is formed between the thermal spray bonding layers 50. The thermal spraying layer 50 is formed on the boundary region 50 and the central region 53 in the longitudinal direction.

This is for obtaining two plate materials in one manufacturing process and can be made of two cladding plates in which the thermal spray bonding layer formed in the central region is cut in the longitudinal direction to form a thermal spray bonding layer in the boundary region .

In another embodiment, the cladding sheet may include a plurality of spray bonding layers, and various modifications may be possible.

Hereinafter, a cladding pipe which is another aspect of the present invention will be described.

9 shows an embodiment of a cladding pipe according to the present invention. The cladding pipe includes a cladding plate including a first plate 110, a second plate 120 and a bonding layer 140 and a bonding portion 130 in which the longitudinal ends of the plate are bonded to each other.

The first plate member 110 is preferably made of a material having a higher melting point and a higher tensile strength than the second plate member 120 and the second plate member 120 is preferably made of a material And is made of a material having a melting point lower than that of the first plate member 110. [

The material of the first plate 110 and the second plate 120 may be iron (Fe), iron alloy, high carbon steel, stainless steel, nickel, cobalt, copper, copper, aluminum, For example, in the case of manufacturing a water pipe, stainless steel may be used for the inner surface of the second plate 120, and carbon steel may be used for the outer surface of the first plate 110. At this time, the first plate 110 preferably has a higher melting point than the second plate 120.

The first plate 110 and the second plate 120 include a bonding layer 140 for bonding. The bonding layer 140 is preferably composed of the thermal spray bonding layer and the non-thermal bonding layer as described above. However, it is preferable that the bonding layer 140 is formed of a clad laminate having two different plate materials, However, the metal bonding layer may cause another problem in that another melting point becomes another metal material.

The joining portion 130 includes a second joining portion 132 to be joined at the outside of the open pipe and a first joining portion 131 to be joined at the inside of the open pipe.

The second joining portion 132 is mainly a portion joining the end portions of the first plate members 110. When the open tube is formed, the second joining portion 132 is located outside the pipe and the gap between the plate members is large, . Particularly, when the thickness of the cladding plate is increased, the distance between the plate materials increases in proportion to the thickness, which is useful as a bonding method in this case. For example, it is preferable that the metal material is the same as the constituent of the first plate 110 for the up welding, and argon welding, arc welding, or the like can be used as the welding method.

The first joint part 131 is located inside the pipe when the open tube is formed, and both end parts of the second plate member 120 are mainly brought into contact with each other by the pressure of the roller, so that the ends of the second plate member 120 are melted and fired, . In this case, a separate welding material may not be used for the joining. For example, it is preferable that the end portion of the second plate member 120 is locally heated and melted and fired to join by the high frequency induction heating skin effect.

Meanwhile, although the first joints 131 described above are described as being fused and fired at the ends of the second plate member 120, a part of the first plate member 110 may also be melted and fired at the same time during the heating process, have. That is, the end portions of the second plate member 120 and the end portions of the first plate member 110, which have different melting points, can be simultaneously melted.

This is because when the first plate 110 and the second plate 120 are heated to a temperature higher than the melting point of the second plate 120 and lower than the melting point of the first plate 110 due to heat conduction even though they have different melting points, This is because the plate member 120 may be in a state where the first plate member 110 is partially melted without being completely melted due to heat conduction. Therefore, the first joint 131 is not merely a joint between the end portions of the second plate 120, but a junction where both ends of the open tube are fused to each other and joined together.

In this case, before the high-frequency induction heating as the first bonding step, the second bonding portion 132 of the first plate 110 having a high melting point is locally heated in advance to preheat the first plate 110, It is advantageous for the metal of the plate material 110 and the metal of the second plate material 120 to melt at the same temperature.

Further, when the difference in melting temperature of the material of each plate material is 70 ° C or less, and the thickness of the cladding steel sheet material is 7 mm or less, the clad steel pipe joint can be completed only by the high frequency induction heating joining method without the need for upset welding. That is, in this case, the joint portion may be formed only by the first joint portion 131.

By constructing the joint as described above, even when the plates having different melting points are cladded, the pipe can be manufactured by joining the ends without bonding defects.

 In the above-described embodiment, two plate materials different from each other are used, but the same can be applied to the case of joining plate materials in triplicate. For example, the present invention is also applicable to manufacturing of stainless steel at the innermost side, carbon steel at the middle, and stainless steel at the outermost side.

Hereinafter, a method of manufacturing a cladding pipe, which is another aspect of the present invention, will be described.

10 is an explanatory view of a manufacturing method of a cladding pipe. According to this, the manufacturing method of the cladding pipe includes a supplying step, a forming step, and a bonding step.

The supplying step is a step of supplying a cladding plate having a first plate having a first melting point and a second plate having a second melting point lower than the first melting point. For example, the melting point of steel as the first plate is 1500-1530 ° C, and the melting point of stainless steel as second plate is 1371-1454 ° C.

The forming step is a step of forming the end portion in the longitudinal direction of the cladding plate material by forming the cylindrical open tube with the first plate material as the outer surface and the second plate material as the inner surface.

The joining step includes a first joining step of joining the end portions of the cylindrical open pipe and joining the ends of the cylindrical open pipe to each other by heating and pressing and melting the inner end portion of the open pipe and a second joining step .

Since the melting point is low in the first bonding step and is located on the inner side of the pipe, the ends are contacted with each other or the interval is narrow. At this time, pressurization is performed as part of the tube making process.

High frequency induction heating welding can be used as a method of melting and joining the ends. An induction coil 220 is installed outside the tube and heated to a temperature at which the second plate can melt, Are melted and joined together.

At this time, the surface of the heated object is heated due to the skin effect of induction heating, and the induction heating current loss effect is concentrated on the end of the second plate having a low melting point, so that only the end portion is melted.

On the other hand, the first plate and the second plate can be melted at the same time by heating the temperature to be heated in the first joining step to a temperature intermediate the melting point of the first plate and the second plate. In this case, as described above, not only the first plate but also a part of the second plate can be melted to form the first joint.

On the other hand, in order to prevent surface oxidation due to high temperature during high-frequency welding, it is preferable to continuously spray argon gas, nitrogen gas, mixed gas, etc. inside and outside of the tube in a reducing atmosphere.

The first joint formed after the high-frequency welding may form a bead protruding inward and outward. The bead may further include a rolling step to constitute a rolling roll so as to be opposed to the outside and inside of the welded portion of the cylindrical pipe.

That is, when the joining step is continued, the bead of the welded portion generated at the inside and outside of the pipe is pushed outwardly by using the internal rolling roll in the outward direction of the pipe, The external rolling roll positioned so as to perform a rolling process by applying a rolling force in an inward direction of the pipe to perform a rolling process so that a welded portion protruding from the inside and outside of the cylindrical pipe is flush with the other surface.

On the other hand, the first joint may have a very fine air layer at the site, but the weld is performed at 500 to 800 ° C, which is a partially cooled temperature after welding, to have a welded joint plasticity structure. Thus, Can be continuously produced.

In the second joining step, the first plate has a high melting point, is located outside the tube and has a wide gap between the ends. Therefore, when joining the ends, the melting point can be lowered, And the end portions are joined by the breeding welding which additionally supplies the material for the growth of. At this time, it is preferable to use a growth material having a third melting point which is lower than or equal to the second melting point of the second plate, and the third growth material is preferably a metal. For example, when stainless steel and carbon steel are used, carbon steel may be used as the material for growth.

At this time, it is preferable to sequentially perform the growth welding using one or more welding machines. Also, the upset welding may be performed after the bead surface rolling process to remove the beads immediately after the first bonding step or the first bonding step, depending on the production pipe thickness.

On the other hand, as described above, when the difference in melting temperature of the material of each plate material is 70 ° C or less and the thickness of the cladding steel sheet material is 7 mm or less, the clad steel pipe joint can be completed only by the high- This is because when the first plate and the second plate are heated to a temperature higher than the melting point of the second plate by heat conduction and lower than the melting point of the first plate even though the melting points of the first plate and the second plate are different from each other, A part of the plate material may be melted.

At this time, before the high-frequency induction heating as the first joining step, the joining portion of the end portion of the first plate having a high melting point is locally heated in advance to preheat the first plate, whereby the metal of the first plate and the second plate It is advantageous to melt at the same temperature.

The cladding plate according to the present invention preferably has a thermal spraying layer at a boundary region (edge) in the longitudinal direction in which the first plate and the second plate are joined together And when the end of the open tube is welded by forming the non-welded joint layer in the central region, the welded joint layer of the metal is exposed to the end, so that it can be welded.

However, if the thermal sprayed joint layer alone is not heated locally during high frequency welding, the non-welded joint layer, which is an organic layer, may be burned. Therefore, the impidermay core 210 is embedded in the cladding pipe as described above, . At this time, it is preferable that the cooling water is injected or filled into the remaining portions except the welding portion to lower the temperature.

After performing the above-described processes, a clad pipe of a certain length is installed in another separate coating area manufacturing line to prevent oxidation corrosion on the outside of the pipe. In order to prevent corrosion of the outside of the pipe, coal tar enamel, tar epoxy resin coating, liquid epoxy resin coating, Stainless steel clad pipe is manufactured by spray coating and taping of polyethylene (PE) coating or taping, or polyethylene (PE) pipe outside of clad steel pipe by heat shrinking method. .

While the invention has been shown and described with reference to certain preferred embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. This is possible.

Therefore, the scope of the present invention should not be limited by the described embodiments, but should be determined by the equivalents of the appended claims, as well as the appended claims.

1 - first plate 2 - second plate
3 - first spray layer 4 - second spray layer
5 - Rolling Roller 6 - Case
7, 50 - Spraying layer 51 - Spinning layer
52 - mixed bonding layer 110 - first plate
120 - Second plate 130 - Joint
140 - bonding layer 230 - rolling roll
220 - Induction coil 210 - Impede core
P - pipe

Claims (20)

A first plate having a first melting point, and
And a second plate having a second melting point lower than the first melting point are joined to each other to bond the both ends of the clad plate to each other,
Wherein an outer surface of the clad pipe is the first plate,
Wherein the inner surface of the clad pipe is the second plate and the joining portion of the both ends has a first joining portion at least a part or all of the end portion of the plate material is melted and bonded. The method according to claim 1,
And a second joint between the opposite ends of the first plate, the second joint being joined with a growth material filling the gap between the opposite ends. 3. The method of claim 2,
Wherein the material of the second joint has a third melting point lower than or equal to the second melting point. The method according to claim 1,
The material of the first plate is steel,
Wherein the material of the second plate is stainless steel. The method according to claim 1,
Wherein the cladding plate having the first plate and the second plate bonded thereto is joined to the thermal spraying bonding layer formed by thermal spraying and the thermal bonding layer not depending on thermal spraying. 5. The method of claim 4,
Wherein the non-bonding layer is formed using a metal bonding or an organic adhesive. 5. The method of claim 4,
Wherein the thermal spray bonding layer is formed in a boundary region in a longitudinal direction in which the first plate and the second plate are jointed, and the non-thermal spray bonding layer is formed in a central region where the thermal spray bonding layer is not formed. The method according to claim 1,
And a clad pipe is further provided on the outer surface of the clad pipe. The method according to claim 1,
Wherein the first joining portion is formed by melting both ends of the second plate and a portion of both ends of the first plate. A supply step of supplying a clad sheet material to which a first plate having a first melting point and a second plate having a second melting point lower than the first melting point are bonded;
A forming step of forming an end portion in the longitudinal direction of the clad sheet material by forming the cylindrical open tube with the first plate material outside and the second plate material inside;
And a first joining step of joining and joining the ends of the cylindrical open tube, wherein at least a part or all of the ends are melted and joined to each other. 11. The method of claim 10,
And a second joining step for joining the gap between the end portions of the first plate member by performing the warm-up welding. 11. The method of claim 10,
Wherein the first joining step melts the end portion by high-frequency induction heating. 11. The method of claim 10,
Wherein the clad sheet material comprises a thermal spray bonding layer in at least one region. 11. The method of claim 10,
Wherein the clad sheet material includes a thermal spray bonding layer in at least one region and a non-thermal bonding layer in another region,
Wherein the cost bonding layer is formed using an organic adhesive or a metal. 15. The method of claim 14,
Wherein the thermal spray bonding layer is formed in a boundary region in a longitudinal direction in which the first plate and the second plate are joined together and the non-thermal spray bonding layer is formed in a central region where the thermal spray bonding layer is not formed. 13. The method of claim 12,
Wherein the high frequency induction heating is performed by locally heating an inner side of the end portion by incorporating an Impeder core inside a cylindrical open tube. 11. The method of claim 10,
Wherein the first joining step injects cooling water to the remaining portions except for the joining portion of the cylindrical open tube end or proceeds with the cooling water filled in the open tube. 11. The method of claim 10,
Wherein the first plate is a steel plate material,
Wherein the second plate is a stainless steel plate. 11. The method of claim 10,
Wherein the first joining step is performed inside and outside the cylindrical open tube in an inert atmosphere or a reducing atmosphere. 11. The method of claim 10,
Further comprising a rolling step of pressing and flattening the beads of the joint portion generated after the first joining step.

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