JPH09174147A - Manufacture of multiplex winding metallic pipe and device thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a high quality multiplex winding metallic pipe having extremely a high adhesion between the multiplex winding walls and at seam parts by almost uniformly pressing the outer peripheral surface of a pipe body from the outer part, press-welding the walls mutually in radial direction, diffusing a diffusion metal into matrix in the pipe body and cooling. SOLUTION: An hoop material 11, e.g., coated with a copper as the diffusion metal is uncoiled from an uncoiler 10 and formed into a pipe body having, e.g., a double walls with a multiplex wind forming device 1 and introduced into a heating device 2. In the heating device 2, the electric current is supplied to the pipe body from a DC electric source 5 through plural conductive rolls 4, and the pipe body is heated until the copper between the walls starts to diffuse to the matrix of the pipe body 12 with the resistant heat generation of the pipe body. Successively, the multiplex winding metallic pipe is almost uniformly pressed from the outer part in the radial direction with pressing rolls 6 or dies 7 and each wall of the multiplex winding metallic pipe is mutually presswelded in the radial direction with this pressing. Therefore, gap, in which mutually diffused joining layer between the diffusing metal and pipe body matrix does not exist, is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for manufacturing a multi-winding metal tube by winding a hoop material (metal strip material) and performing diffusion bonding with a diffusion metal.

[0002]

2. Description of the Related Art As a method of manufacturing a multi-rolled metal pipe, a hoop material (metal strip) having a copper brazing material applied to one entire surface thereof is plastically deformed into a pipe by a molding apparatus, and the multi-turned pipe is formed. After the brazing material between the walls is melted by a heating device, the molten brazing material is solidified by a cooling device to produce a product. As a method for melting the brazing material of the multi-turn metal tube in this method, there are a method using an electric furnace and a method using a resistance heating method by energization. The method using an electric furnace is a method in which a metal tube formed into multiple windings by a forming apparatus is cut into a fixed length, and the multi-wound metal tubes having the predetermined length are sequentially sent to an electric furnace to melt the brazing material. In the resistance heating method by energization, current is applied to the tube via two electrodes provided at intervals in the length direction of the tube continuously coming out of the molding device, and the tube is heated. This is a method in which the brazing material is melted by resistance heating and brazing is performed continuously (US Patent No. 27461).
No. 41, West German Patent No. 813839, etc.).

[0003]

However, the conventional method of manufacturing a multi-turn metal tube has the following problems. That is, in the multiple roll forming process, due to wear of the forming tool incorporated in the forming apparatus, mechanical properties and dimensional changes of the long hoop material (usually 1000 m or more) wound in a coil shape, and the like There may be a gap in the inner part or the inner and outer seam parts may peel off. In the case of a multi-winding metal pipe in such a state, even if the brazing material layer does not adhere to each other even after brazing, there are voids in some places, resulting in poor adhesion and poor seam adhesion. The function as piping was not obtained, and it had to be treated as a defective product.

Further, since the conventional method has no means for eliminating the gap between the multiple winding walls generated in the molding step, the material must be selected in consideration of the mechanical properties of the hoop material, such as springback. In other words, the selection width of the material is narrow, and the hoop material having a length of usually 1000 m or more is molded as it is without being corrected for variations in each dimension. Further, assuming the existence of a gap between multiple winding walls generated in the forming process, a large amount of brazing filler metal is required, the cost of brazing filler metal such as copper is high, and the brazing filler metal layer has to be thick. The use of the brazing filler metal results in a large amount of the brazing filler metal diffusing into the tubular body, which may cause a problem of embrittlement of the base metal, which is not preferable.

The present invention has been made in view of the above problems of the prior art. For example, even if there are variations in the dimensions of a long hoop material, the hoop material is corrected by heating and molded, so that the multiple winding wall is formed. It is possible to manufacture high-quality multi-winding metal tubes with extremely good adhesion between seams and seams, and it is possible to improve the selection range of hoop material, and because the temperature in the heating process is low, there is a thermal effect on the base material. Since the amount of diffusion metal used is small and there is no gap between multiple winding walls, the amount of diffusion metal used can be kept to the required minimum, and the amount of diffusion to the tube body can be reduced to prevent embrittlement of the base material. It is intended to propose a method for manufacturing a metal tube and an apparatus for carrying out the method.

[0006]

In the method of manufacturing a multi-winding metal tube according to the present invention, at least the outer peripheral side of the diffusion metal between the walls of the multi-winding tube can be diffused into the tube body by heating. When the temperature is lower than the melting point, the outer peripheral surface of the tubular body is pressed substantially uniformly from the outside in the radial direction to press the walls against each other in the radial direction and to diffuse the diffusion metal into the tubular body base, Then, it is characterized by cooling. In this case, the temperature below the melting point of the diffusion metal is set according to the material of the diffusion metal and hoop material used. Further, upon cooling, the diffusion metal which is diffusible and has a temperature lower than the melting point is cooled to a temperature lower than the diffusible temperature of the diffusion metal simultaneously with the radial pressure contact and diffusion, or by cooling as quickly as possible.

As an apparatus for carrying out the method of the present invention, a molding apparatus for molding a hoop material on one surface or both surfaces of which a diffusion metal is formed into a multi-winding metal tube body, and a space between the walls of the multi-winding metal tube body. In a multi-winding metal pipe manufacturing apparatus comprising a heating device for diffusing a diffusion metal into the tubular body and a cooling device for cooling the heated diffusion metal, the heating device can diffuse the diffusion metal into the tubular body. And means for heating the outer peripheral surface of the multi-winding metal tubular body substantially uniformly from the outer side in the radial direction so as to press the walls in the radial direction against each other. Is provided in the heating device. Further, the pressure contact means in this apparatus is characterized by comprising one or more sets of press rolls or one or more dies, and one set of press rolls having a structure of three is used, and The curvature is equal to or slightly smaller than the curvature of the outer diameter of the multi-winding metal tube body. Further, means for supporting the inner peripheral surface of the tubular body corresponding to the pressing roll or the die is further provided, and a core metal is used as the supporting means.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, when at least the outer peripheral side of the diffusion metal between the walls of the tubular body formed into multiple turns is capable of diffusing into the tubular body by heating and is at a temperature below the melting point, The outer peripheral surface of the tubular body is pressed substantially uniformly from the outside in the radial direction by a press contacting means composed of, for example, one or more pairs of pressing rolls or one or more dies, and the walls are pressed against each other in the radial direction, whereby a diffusion metal is formed. Are pressed into the tubular body while being diffused, the number of voids between the walls where there is no mutual diffusion bonding layer between the diffused metal and the tubular body is reduced or eliminated.

In the present invention, the method of applying diffusion metal to one or both sides of the hoop material and providing the diffusion metal between the walls of the tubular body to perform diffusion bonding is that the pressure-bonding means causes a gap between multiple winding walls. The amount of diffusion metal used can be kept to a minimum because of the close contact, and therefore, when the diffusion metal is diffused into the tube body, the diffusion amount of the diffusion metal into the base material is reduced and the embrittlement of the base material is prevented. This is because. In addition, when the diffusion metal is applied to only one side of the hoop material, the amount of the diffusion metal used is further reduced, and the diffusion amount of the diffusion metal to the base material can be further reduced,
Further, when the diffusion metal is applied to both sides of the hoop material, the diffusion metal is diffused into the base material by pressure welding, and the diffusion metals are also diffusion-bonded to each other, so that the bonding strength is further improved. On the other hand, as a means for providing the diffusion metal on one side or both sides of the hoop material, there are various methods such as ordinary plating, thermal spraying or a method using a clad material.

As the pressure contact means, for example, a method using an electric current roll can be considered, but in the case of the electric current roll,
It is made of copper alloy for stable supply of electric current, and has poor wear resistance and low high-temperature oxidation and high-temperature strength. As a result, the roundness and dimensional accuracy of the tubular body are affected, and the roll life is extremely short, making it difficult to put into practical use.
Therefore, in the present invention, without considering the conductivity,
Carbide with abrasion resistance, high temperature oxidation and high temperature strength (W
In order to be able to use a roll or die dedicated to pressing such as C), a method of separately providing a pressure contact means for the pipe body is adopted.

As the diffusion metal in the present invention, there are, for example, copper or copper alloy series, nickel series, aluminum series, etc., and their melting points are 1083 ° C. or less for copper, 890 ° C. or less for nickel series, and aluminum. If it is a system, the temperature is 590 ° C or lower.

The hoop material is iron (SPCC).
Etc.), stainless steel (SUS304, SUS316, etc.),
Copper (C1220R, C2600R, NCuR, etc.), aluminum (A3003, A5052, etc.), etc. are available.

In the present invention, the temperature condition of the diffusion metal when the outer peripheral surface of the pipe body is pressed from the outside is limited to a temperature below the melting point that allows the diffusion metal to diffuse into the base material of the pipe body. This is because, when the coating film or the diffusion material plating film is applied, the plating film applied to the hoop material is melted down at a temperature equal to or higher than the melting point, and the surface quality of the tubular body is deteriorated to lower the commercial value. That is, when the temperature is lower than the melting point, the plating film applied to the hoop material does not burn through, so that a tube having a uniform film thickness and good corrosion resistance can be obtained. For example, when copper is used as the diffusion metal, the diffusion bond of copper is slow and weak at temperatures lower than 800 ° C., the mechanical strength as a metal tube cannot be obtained, and the feed rate of the tube must be extremely low. ,
On the other hand, if the temperature exceeds 1083 ° C., the copper will flow, and the copper may pool on the inner and outer surfaces of the metal tube to deteriorate the surface properties. Therefore, when copper is used as the diffusion metal, it is necessary to set the temperature that is capable of diffusing into the tubular body and lower than the melting point to 800 ° C. or higher and lower than 1083 ° C. The “diffusible temperature” in the present invention does not simply mean the temperature at which the metal atoms constituting the diffusion metal start diffusing through the tubular body, but is practically considered in terms of productivity (economic efficiency). ) Means the lowest temperature at which diffusion begins through the tube body delivered at an effective feed rate.

In the present invention, the heating temperature of the tubular body is appropriately set according to the material of the diffusion metal and the hoop material to be used, but since the heating temperature in the heating step is relatively low, the base material (hoop material) is used. The heat effect on is especially small.

In the present invention, since one end side of the outermost wall of the multi-winding metal tube is pressed by the pressure contact means composed of a press roll or a die, it is preferable to press it forcibly from the outside. Even if there are variations in the respective dimensions, the outer seam portion is prevented from peeling off by fitting with the inner wall and the adhesion of the portion is improved.

Further, the multi-winding metal tube can be pressed by a pressing roll or a die having a water cooling structure to cool the multi-winding metal tube to a temperature below the diffusible temperature as quickly as possible. Incidentally, instead of the water-cooled press roll or die, or in addition to this, as the cooling means, it is also possible to cool the outer peripheral surface of the multi-winding metal pipe body by a refrigerant injection nozzle arranged immediately after the press roll or die. Also in this case, the pressed state between the walls can be maintained, excessive diffusion of the diffusion metal into the tubular body can be prevented, and the growth of crystal grains can be suppressed.

Further, in the present invention, after the stress of the base material is released by heating, or the wall is pressed again while releasing the stress, it is not necessary to select the material in consideration of mechanical properties such as springback. At the same time, even if there are variations in the dimensions of the long hoop material, the adhesion between the walls of the multi-winding tube and the seam portion is good, and a high-quality multi-winding tube can be manufactured.

[0018]

1 is a schematic view showing an apparatus according to an embodiment of the present invention, FIG. 2 is an enlarged schematic view showing a pressure forming roll of a multi-winding metal tube in the same apparatus, and FIG. 3 is a multi-winding apparatus in the same apparatus. It is a vertical side view which expands and shows the die | dye as another pressure contact means of a metal tube, 1 is a multi-winding forming device, 2 is a heating device, 3 is a cooling device, 4 is an energizing roll (rotating electrode), 5 is direct current. A power supply, 6 is a press roll, 7 is a die, 10 is an uncoiler, 11 is a hoop material (metal strip steel) plated with a diffusion metal on one side or both sides, and 12 is a multi-winding tube body.

Here, the multi-winding molding apparatus 1 is composed of, for example, a multi-stage molding roll 1-1, and the uncoiler 1
The hoop material 11 rewound from 0 is continuously formed into a cylindrical shape. Further, the heating device 2 employs a resistance heating method using a plurality of pairs of energizing rolls (rotating electrodes) 4 arranged at appropriate intervals in the line direction, for example. The inside of the heating device is in a non-oxidizing atmosphere or a reducing gas atmosphere.

The presser roll 6 is, for example, as shown in FIG.
It is a three-roll type consisting of one set of three rolls 6-1 and has a structure in which the outer peripheral surface of the multi-winding tubular body 12 molded by the molding apparatus 1 is pressed uniformly from the outside in the radial direction. The curvature of the groove of the pressing roll 6 is set to be equal to or slightly smaller than the curvature of the outer circumference of the multi-winding tube, that is, the final roll of the multi-winding forming apparatus 1. This is because the pressing force is applied to the multi-winding tube body almost uniformly. Also, this presser roll 6
Can have a water-cooling structure to serve as a cooling means for cooling the multi-winding body, but this pressing roll 6 can diffuse a diffusion metal that is diffusible into the base material of the multi-winding body 12 and has a temperature lower than the melting point. By uniformly pressing from the outer side in the direction, it is possible to surely and quickly diffuse between the tubular body and the diffusion metal.

Further, the die 7 is used in place of the pressing roll 6, and its structure is, as shown in FIG. 3, the outer peripheral surface of the multi-winding tube body 12 molded by the molding apparatus 1 as in the pressing roll 6. The structure is such that the pressure is applied almost uniformly from the outside in the radial direction. Also in the case of this die, the cooling water passage 7-1 is provided inside.
It is also possible to provide a water-cooled structure by using this die 7
By diffusing into the base material of the multi-winding tube 12 and pressing the diffusion metal at a temperature lower than the melting point evenly from the outer side in the radial direction, the diffusion between the tube body and the diffusion metal is surely and quickly performed. Can be made.

The pressing roll 6 or the die 7 should be installed at a position where it is pressed while the diffusion metal between the walls of the multi-winding tube is in a heating state below the melting point at a temperature at which the diffusion metal can diffuse into the tube body. Therefore, it is provided in the heating device 2.

The cooling device 3 includes a press roll 6 or a die 7.
Is installed on the downstream side of the multi-winding tube, and a number of refrigerant injection nozzles (not shown) are arranged so that the outer circumference of the multi-winding tube can be uniformly cooled. In order to complete the above, a large number of refrigerant nozzles (not shown) are arranged. Specifically, for example, a cooling jacket type in which a number of nozzle holes are provided in the inner periphery is used, and a structure in which a refrigerant is blown from the nozzle holes to a multi-winding pipe passing therethrough is used. As the refrigerant, a gas such as an inert gas or a reducing gas is mainly used, but a liquid such as heat carrier oil or water can also be used.

In the multi-winding metal pipe manufacturing apparatus having the above-mentioned structure, the hoop material (SPCC) 11 on one or both sides of which copper is applied as a diffusion metal is unwound from the uncoiler 10 and, for example, in the multi-winding forming apparatus 1. It is formed into a tubular body having a heavy wall and introduced into the heating device 2. In the heating device 2, the DC power source 5 energizes the tube through a plurality of energizing rolls 4, and the resistance heat of the tube causes the copper between the walls to start diffusing into the base material of the tube 12. Heat until The temperature at this time is 800 ° C. or higher and lower than 1083 ° C. Then, the pressing roll 6 or the die 7 presses the multi-winding metal tube substantially uniformly from the outside in the radial direction, and by this pressing, the walls of the multi-winding metal tube are pressed against each other in the radial direction. At this time, since the diffusion metal between the walls is beginning to diffuse into the tubular body, the walls are brought into close contact with each other by the pressing action of the pressing roll 6 or the die 7, and the diffusion metal and the tubular body are mutually diffusion-bonded. The voids where there are no layers are reduced.

Further, one end side (seam portion side) of the outermost wall of the multi-winding metal tube body is provided with the pressing roll 6 or the die 7.
Is forcibly pressed by, so that the outer seam portion is prevented from peeling off by fitting in and adhering to the inner wall.

Further, since both the pressing roll 6 and the die 7 have a water-cooling structure, the multi-winding metal pipe is pressed to diffuse the diffusion metal, and at the same time, it is cooled, so that it can be diffused into the pipe body and the diffusion below the melting point. The metal is cooled to below the diffusible temperature of the diffusion metal. Due to such a cooling effect, the pressure contact state between the walls is maintained, excessive diffusion of the diffusion metal into the tubular body can be prevented, and the growth of crystal grains is suppressed.

As the cooling means for cooling the multi-winding tube as quickly as possible, in addition to the water-cooling type holding roll 6 or die 7, a nozzle 13 is provided immediately after the holding roll 6 or die 7. The nozzle 13 is used to inject a coolant to cool the diffusion metal to a temperature below the diffusible temperature to maintain pressure contact between the walls and prevent the diffusion metal from excessively diffusing into the tubular body. The growth of crystal grains of the material can also be suppressed.

The multi-winding tube 12 exiting the heating device 2 is further cooled by the cooling device 3 arranged on the downstream side of the pressing roll 6 or the die 7, so that the outer peripheral surface of the multi-winding tube is cooled. The diffusion bonding of the diffusion metal between the walls is completed.

In the multi-winding metal pipe of the present invention manufactured by the above-described multi-winding metal pipe manufacturing apparatus, a diffusion bonding layer having no voids and no adhesion between the walls and good adhesion can be obtained.

In the above-mentioned multi-winding metal pipe manufacturing apparatus, the pressing roller 6, the die 7, and the like are not necessarily installed immediately after the final energizing roll 4, but, for example, as shown in FIG. The same operation and effect can be obtained even if it is installed between 4 and the energizing roll 4 in the preceding stage.

As the heating means for the multi-winding metal tube, instead of the resistance heating method, as shown in FIG.
A high-frequency heating coil 15 may be employed. In this case, since an energizing roll is not necessary, it is only necessary to provide a guide roll 16 at the entrance of the heating device. Further, as a heating means for the multi-winding tube, a general heating furnace known from Japanese Patent Publication No. 29-4613 may be used.

Further, on the inner peripheral surface of the tube body corresponding to the pressing roll 6 or the die 7, a means for supporting the inner peripheral surface,
For example, as shown in FIG. 6, a means for supporting by a cored bar 18 attached to the tip of the rod 17 can be additionally provided. In the case where such a tubular inner peripheral surface supporting means is provided,
The pressing force of the presser roll 6 or the die effectively acts on the tubular body. When the cored bar 18 is used,
It is effective to circulate water or the like inside the core metal to cool it.

Further, the above embodiment shows an apparatus in which the multi-winding tube body is formed, the diffusion metal is heated, and the diffusion metal is continuously cooled until the multi-winding metal tube is manufactured from the hoop material 11. However, as shown in FIG.
After molding, the sample is cut to a fixed length, the cut-off tube is sent to the heating device 2 by the sending roll 14 to heat the diffused metal, and then the cooled diffused metal is cooled by the cooling device 3. It can also be configured to complete diffusion bonding. FIG.
In the embodiment according to the present invention, a multi-winding metal pipe manufacturing apparatus according to the present invention, which is provided with a plurality of tubes, is used to mass-produce a large number of pipes that are formed at high speed and efficiently and are cut to a predetermined length using a conventional multi-winding pipe forming apparatus. Therefore, productivity can be significantly improved.

[0034]

As described above, according to the present invention,
The following effects are obtained. (1) Since the walls are pressed against each other while the diffusion metal applied to at least one surface of the hoop material is being diffused into the tubular body, the diffusion metal and the tubular body are not separated from each other between the walls. Voids generated due to the absence of the diffusion bonding layer can be significantly reduced. (2) Since one end side of the outermost wall of the multi-winding tube is pressed by the pressure contact means composed of a press roll or a die, it is preferably forcedly pressed from the outside. The outer seam is prevented from peeling off due to the diffusion of the above into the tubular body. (3) Since the cooling of the multi-winding metal pipe is performed by pressing in the radial direction and diffusing at the same time or as quickly as possible, the pressure contact state between the walls is maintained and the diffusion metal is excessively applied to the pipe base material. Diffusion can be prevented, and the growth of crystal grains can be suppressed. (4) After the residual stress of the base material due to forming is released by heating, or between the walls is pressed again while releasing the residual stress, mechanical properties such as wear of the forming tool incorporated in the forming device, springback, and hoop material. It is no longer necessary to select the material in consideration of the variation in each dimension, and the selection range of the material can be improved. (5) Since the heating temperature in the heating step is low, the heat effect on the base material can be reduced, and since the multiple winding walls are diffused while being pressed against each other, the amount of the diffusion metal used can be kept to the minimum necessary amount. Together with this, the diffusion of the diffusion metal into the tubular body is reduced, so that deterioration of the base material can be prevented.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing the overall configuration of an embodiment of the present invention.

FIG. 2 is an enlarged schematic view showing a pressing roll of a multi-winding metal tube in the same apparatus.

FIG. 3 is a vertical cross-sectional side view showing, in an enlarged manner, a die as another pressure welding means for a multi-winding metal tube in the same apparatus.

FIG. 4 is a schematic view of a heating device showing an example of changing the installation location of a press roll in the same device.

FIG. 5 is a schematic view of a heating device showing another heating means of the multi-winding metal tube body in the same device.

FIG. 6 is a schematic view showing an example of an inner peripheral surface supporting means of a multi-winding metal tube body in the same apparatus.

FIG. 7 is a schematic view showing a main part of an apparatus according to another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Multiple winding forming device 2 Heating device 3 Cooling device 4 Energizing roll (rotating electrode) 5 DC power supply 6 Holding roll 7 Dice 10 Uncoiler 11 Hoop material (metal strip steel) 12 Multiple winding metal tube body 13 Nozzle 15 High frequency heating coil 16 Guide Roll 17 Rod 18 Core

Claims (8)

[Claims] 1. The outer peripheral surface of the pipe body is formed when at least the outer peripheral side of the diffusion metal between the walls of the pipe body formed into multiple windings is capable of diffusing into the base body of the pipe by heating and has a temperature lower than the melting point. A method for producing a multi-winding metal tube, comprising: pressing the walls substantially uniformly from the outside in the radial direction to press the walls against each other in the radial direction, diffusing a diffusion metal in the tube body, and then cooling. 2. Cooling the diffusible metal having a temperature lower than the melting point and capable of diffusing to a temperature lower than the diffusible temperature of the diffusing metal by cooling that is performed at the same time or as quickly as possible when the diffusive metal is pressed into the radial direction and diffused. The method for producing a multi-winding metal tube according to claim 1, wherein 3. A molding device for molding a hoop material, at least one surface of which is provided with a diffusion metal, into a multi-winding tube body, and a heating device for diffusing the diffusion metal between the walls of the multi-winding tube body into the tube body. In the multi-winding metal pipe manufacturing apparatus, which comprises a cooling device that cools the heated diffusion metal, the heating device has a function of heating the diffusion metal so that the diffusion metal can diffuse into the pipe body and is below the melting point. At least one means for pressing the outer peripheral surface of the multi-winding tube from the outside in the radial direction substantially uniformly to press the walls against each other in the radial direction is provided in the heating device. Multi-winding metal pipe manufacturing equipment. 4. The multi-winding metal pipe manufacturing apparatus according to claim 3, wherein the pressure contact means is composed of one or more sets of press rolls or one or more dies. 5. The manufacturing apparatus for a multi-winding metal tube according to claim 4, wherein the one set of pressing rolls has a structure of three pieces. 6. The manufacturing apparatus for a multi-winding metal pipe according to claim 4, wherein the curvature of the groove of the pressing roll is equal to or slightly smaller than the curvature of the outer diameter of the multi-winding metal pipe body. 7. The multi-winding metal pipe manufacturing method according to claim 4, further comprising means for supporting the inner peripheral surface of the inner surface of the tube body corresponding to the pressing roll or the die. apparatus. 8. The manufacturing apparatus for a multi-winding metal tube according to claim 7, wherein the supporting means is made of a cored bar.