JPH09174148A - 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 an extremely high adhesive strung between the multiplex winding walls and a seam parts by changing transfer velocity of a pipe body, giving a tension force in a pipe axial direction to the pipe body, press-welding the walls mutually in the radial direction, diffusing a diffusion metal into matrix in the pipe body and cooling. SOLUTION: Pressing rolls 7 for the pipe body and pinch rolls 8 are a means for changing the transferring velocity of the pipe body, and out of them, the pressing roll 7 for the pipe body has a structure which almost uniformly presses the outer peripheral surface of the multiplex winding pipe body 11 formed with a forming device 1 from the outer part in the radial direction. On the other hand, the pinch rolls 8 are arranged in the suitable interval at the downstream side of the pressing rolls 7 and this roll diameter is larger than that of the pressing rolls 7 or the rotational speed is changed so that the tension force in the pipe axial direction acts to the pipe body between the pinch rolls and the pressing rolls 7. The interval between the rolls is brought into close contact by the pressing action of this tension force.

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 winding 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 on the coil, and the like, the multiple winding walls are 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, there may be voids where the brazing material layer does not adhere to the wall even after brazing, resulting in poor adhesion and poor seam adhesion. However, 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. However, the selection width of the material is narrow, and the variation of each dimension of the hoop material having a length of 1000 m or more is normally molded without correction. 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-mentioned problems of the prior art. Even if there is a variation in each dimension of a long hoop material, it is corrected by heating and molded. It is possible to manufacture high-quality multi-winding metal pipes with extremely good adhesion between walls and seams, and it is possible to improve the selection range of materials, and since the temperature in the heating process is low, there is no 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, so the amount of diffusion metal into the pipe body is reduced and brittleness of the base metal can be prevented. It is intended to propose a method of manufacturing a tube and a device for carrying it out.

[0006]

According to 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 tube, which is molded and transferred in the multi-winding method, is heated to heat the tube base material. When the temperature is lower than the melting point, the walls are pressed against each other in the radial direction by applying a tensile force in the pipe axis direction to the pipe to change the transfer speed of the pipe. It is characterized in that the diffusion metal is diffused in the substrate and then cooled. In this case, the temperature at which the diffusion metal can diffuse into the tube body and is lower than the melting point is set according to the diffusion metal and the material of the hoop material to be used. Also, when cooling,
It is characterized in that it is cooled at the same time or as soon as possible when it is pressed into the radial direction and diffused. Further, it is characterized in that the outer peripheral surface of the tubular body is further pressed substantially uniformly from the outer side in the radial direction at least immediately before or after the pulling in the axial direction of the pipe.

As an apparatus for carrying out the method of the present invention, a molding apparatus for molding a hoop material having at least one surface coated with a diffusion metal into a multi-winding body, and a diffusion metal between the walls of the multi-winding body. In a multi-winding metal pipe manufacturing apparatus equipped with a heating device for diffusing the pipe body into the pipe body, a cooling device for cooling the heated diffusion metal, and a means for transferring the pipe body to the heating device and the cooling device, Is capable of diffusing into the tube body and is in a temperature state below the melting point, the tube body is pulled in the tube axis direction so that the walls are pressed against each other in the radial direction, and the transfer speed varying means of the transfer device is provided. It is characterized in that it is provided in the heating device. In addition, the transfer speed varying means in this device includes one or more sets of tubular body pressing rolls,
It comprises one set of pinch rolls arranged on the downstream side of the press roll, and is characterized in that a means for making the diameter of the pinch roll larger than the diameter of the press roll or for increasing the rotation speed is used. The set of tubular body pressing rolls has a structure of three, and 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 tubular body. Further, at least one of immediately before and after the transfer speed changing means is further provided with means for pressing the multi-winding tube substantially uniformly from the outside, and the pressing means is one or more sets of press rolls or It is characterized by consisting of dice.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION According to the present invention, when at least the outer peripheral side of the diffusion metal between the walls of the tube formed into multiple turns is diffusible into the tube body and the temperature is below the melting point, one or more pairs of The transfer speed of the tube body is changed by a transfer speed varying means including a tube body pressing roll and a pair of pinch rolls arranged on the downstream side of the pressing roller to apply a tensile force in the tube axis direction to the tube body. Due to this, a reducing force is generated in the pipe body, and the walls are pressed against each other when the diffusion metal begins to diffuse into the pipe body, so the diffusion metal and the pipe body are mutually diffusion-bonded between the walls. The voids where there are no layers are reduced. Further, since one end side of the outermost wall of the multi-winding metal tube is pressed, it is preferably forcibly pressed from the outside. As a result, even if each dimension of the long hoop material varies, the inner wall and Familiarity prevents peeling of the outer seam portion and improves the adhesion of the portion. It is sufficient that the diffusion metal is capable of diffusing into the pipe body at a position where the pipe body abuts at least the pinch roll and is in a state of lower than the melting point, and it is not always possible to diffuse when passing through the pipe body pressing roll. It need not be below the melting point. In other words, the tube body pressing roll can be arranged at a position before heating.

Immediately after the transfer speed varying means, a cooling medium injection nozzle may be arranged so as to cool the outer peripheral surface of the multi-winding tube to serve as a cooling means. Since the diffusion metal in is cooled to below the diffusible temperature of the diffusion metal, the pressure contact state between the walls can be maintained, excessive diffusion of the diffusion metal into the tube body can be prevented, and the crystal of the base material can be prevented. Grain growth can also be suppressed.

The diffusion metal applied to one or both sides in the present invention includes, for example, copper or copper alloy type, nickel type, aluminum type, etc., and their melting points are 1083 ° C. or lower for copper, and nickel type. If it is, it is 890 ° C or lower, and if it is aluminum, it is 590 ° C or lower.

The hoop material is iron (SPCC).
Etc.), stainless steel (SUS304, SUS316, etc.),
There are copper (C1220R, C2600R, NCuR, etc.), aluminum (A3003, A5052, etc.), and the like.

In the present invention, the reason for limiting the temperature condition of the diffusion metal when applying the tensile force in the axial direction to the pipe body is that the diffusion metal can be diffused and the temperature is lower than the melting point. This is because, when the plating film is applied, the plating film applied to the hoop material melts down at a temperature equal to or higher than the melting point, the surface quality of the tubular body deteriorates, and the commercial value decreases. That is, when the temperature is lower than the melting point, the plating film applied to the hoop material hardly burns down, 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 coupling of copper is slow and weak at temperatures lower than 800 ° C., the mechanical strength as a multi-winding 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., copper may flow, and copper may accumulate in the inner and outer surfaces of the multi-winding metal tube to deteriorate the surface properties. Therefore, in the case of copper, it is necessary to set the diffusible temperature 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, a method of providing a diffusion metal on one or both sides of the hoop material and bringing the diffusion metal into contact with the tube body to diffuse the metal is that the heating temperature in the heating step is relatively low and The influence of heat is particularly small, and in order to apply a tensile force in the tube axis direction to the tube body by changing the transfer speed of the tube body, the walls are pressed against each other in the radial direction so that the multiple winding walls are in close contact with each other. This is because the amount of the diffusion metal used can be kept to a minimum, and therefore, when the diffusion metal is diffused into the tubular body, the diffusion amount of the diffusion metal into the base material is reduced and the embrittlement of the base material is prevented. . 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. ,
Since the diffusion metal is diffused into the base material by the pressure welding, and the diffusion metals are also diffusion-bonded to each other, the bonding force 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.

In the present invention, the multi-winding metal pipe can be cooled by being pressed in the radial direction and being diffused at the same time or as quickly as possible. With this structure, the pressed state between the walls is maintained, and 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 walls are pressed against each other 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 condition of close contact between the walls of the multi-winding tube is good, and a high-quality multi-winding tube can be manufactured.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic view showing an apparatus according to an embodiment of the present invention,
FIG. 2 is an enlarged schematic view showing three tubular body pressing rolls in the same apparatus. 1 is a multi-winding forming apparatus, 2 is a tube body transfer roller, 3 is a heating apparatus, 4 is a cooling apparatus, 5 Is an energizing roll (rotating electrode), 6 is a DC power supply, 7 is a tube body pressing roll, 8 is a pinch roll, 9 is a refrigerant injection nozzle, 10 is a hoop material (metal strip steel) having one or both surfaces plated with a diffusion metal. , 11 are multi-winding tubes.

Here, the multi-winding forming apparatus 1 is composed of, for example, a multi-stage forming roll 1-1, and continuously forms the hoop material 10 rewound from an uncoiler (not shown) into a cylindrical shape. It has a structure. Also, the heating device 3
For example, a resistance heating method using a plurality of pairs of energizing rolls (rotating electrodes) 5 arranged at appropriate intervals in the line direction is adopted. The inside of the heating device is in a non-oxidizing atmosphere or a reducing gas atmosphere.

Tube pressing roll 7 and pinch roll 8
Is a means for changing the transfer speed of the pipe body. Among them, the pipe body pressing roll 7 is, for example, as shown in FIG. The outer peripheral surface of the formed multi-winding tube body 11 is pressed substantially uniformly from the outside in the radial direction. The curvature of the groove of the tubular body pressing roll 7 is set to be equal to or slightly smaller than the curvature of the outer circumference of the multiple winding tubular body, that is, the final roll of the multiple winding forming apparatus 1. This is to apply a pressing force uniformly to the multiple winding tube. On the other hand, the pinch rolls 8 are installed at appropriate intervals on the downstream side of the tube body pressing roll 7,
By making this roll diameter larger than the tube body pressing roll 7 or changing the rotation speed, a tensile force in the tube axis direction acts on the tube body with the tube body pressing roll 7. . It is preferable that the pinch roll 8 is also a three roll type like the tubular body pressing roll 7. In this way, the diffusion metal is heated and a tensile force in the tube axis direction acts on the tube body, so that a reducing force is generated in the tube body. At this time, since the diffusion metal between the walls is beginning to diffuse into the base material of the multi-winding tube body 12, the walls are brought into close contact with each other by the pressing action by the tensile force of the pressure contact in the tube axis direction, and the diffusion metal and the tube body The voids that do not have mutual diffusion bonding layers with the 12 substrates are reduced. Further, one end side (seam side) of the outermost wall of the multi-rolled metal tube is adapted to be intimately adhered to the inner wall by pressure contact in the radial direction, and peeling of the outer seam portion is prevented.

Regarding the installation positions of the tube body pressing roll 7 and the pinch roll 8, the walls of the multi-winding tube must be pressed in the radial direction while the diffusion metal between the walls of the multi-winding tube is in a heated state. Therefore, the heating device 3 is provided in the heating device 3. However, the heating device 3 does not necessarily have to be immediately after the final energizing roll 5 as shown in FIG. The effect is obtained.

As a cooling means for cooling the multi-winding tube as quickly as possible after pressure contact in the radial direction, a nozzle 9 is provided immediately after the pinch roll 8 and a refrigerant is jetted from this nozzle to spray the outer periphery of the multi-winding tube. It is possible to cool the surface, and this nozzle cools the diffusible metal that is diffusible and has a temperature below the melting point to a temperature below the diffusible temperature of the diffusive metal to maintain the pressure contact state between the walls and Excessive diffusion into the tubular body can be prevented, and the growth of crystal grains can be suppressed.

The cooling device 3 is installed on the downstream side of the tube pressing roll 7 or the pinch roll 8 and cools the diffused metal in a heated state, and a large number of refrigerants so as to uniformly cool the outer periphery of the multi-winding tube. It has a structure in which an injection nozzle (not shown) is 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 tube manufacturing apparatus having the above-mentioned structure, a hoop material (SPCC) 10 having copper as a diffusion metal plated on one side or both sides is unwound from an uncoiler (not shown) and is then wound in the multi-winding forming apparatus 1. For example, it is formed into a tube having a double wall, and is introduced into the heating device 3 while being transferred at a predetermined speed by the tube transfer roller 2. In the heating device 3, the direct current power supply 6 energizes the tube through a plurality of pairs of energizing rolls 5, and the diffusion metal existing between the walls is diffused to the base material of the tube 12 by resistance heating of the tube. Heat until it is The temperature at this time is 800 ° C. or higher and lower than 1083 ° C. because the diffusion metal is copper.

Then, the diffusion metal applies a tensile force in the axial direction of the pipe between the pipe pressing roll 7 and the pinch roll 8 in a state where the copper between the walls begins to diffuse into the pipe base. Give. As a result, the walls of the multi-winding tube are pressed against each other in the radial direction. At this time, since the diffusion metal between the walls is starting to diffuse into the tubular body, the number of voids where there is no mutual diffusion bonding layer between the diffusion metal and the tubular body is reduced, and One end side of outermost wall (seam side)
Is adapted to be adhered to the inner wall by pressure contact in the radial direction, and peeling of the outer seam portion is prevented.

Further, the multi-winding tube body 11 can be cooled by the refrigerant injection nozzle 9 arranged immediately after the pinch roll 8. In this case, the diffusion metal in the heated state is cooled to a temperature lower than the diffusion temperature of the diffusion metal. To be done. By such cooling, the pressure contact 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. On the other hand, the heating pipe 11 that has exited the heating device is cooled by the cooling device 4 arranged on the downstream side of the pinch roll 8, so that the outer peripheral surface of the multi-winding pipe is cooled and the diffusion metal diffuses between the walls. Joining is completed.

The multi-winding tube of the present invention manufactured by the above-described multi-winding tube manufacturing apparatus has a good adhesion property without voids in which there is no mutual diffusion bonding layer between the diffusion metal and the tube body between the respective walls. A diffusion bonding layer is obtained.

As another embodiment, in the present invention, FIG.
As shown in FIG. 5, immediately before or after the tube body transfer speed varying means including the tube body pressing roll 7 and the pinch roll 8, that is, immediately before the tube body pressing roll 7 or immediately after the pinch roll 8, for example, the tube body pressing roll. The same 3-roll type presser roll 12 as that of No. 7 or the die 15 shown in FIG.
And other pressing means are provided. By doing so, it is possible to further reduce the gaps between the respective walls in which there is no mutual diffusion bonding layer between the diffusion metal and the tubular body, and it is possible to further eliminate the steps in the outer seam portion. Further, by making the press roll 12 or the die 15 have a water cooling structure, this pressing means can be used as a cooling means.

As the heating means for the multi-winding tube, a high frequency heating coil 13 may be employed as shown in FIG. 5, instead of the resistance heating method. In this case, since the energizing roll is not necessary, the guide roll 1 is provided at the inlet of the heating device.
It is only necessary to provide 4. Further, as a heating means for the multi-winding tube body, a general heating furnace known from Japanese Patent Publication No. 29-4613 may be used.

Further, the above-described 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 10. However, as shown in FIG. 6, after forming the multi-rolled tubular body 11, it is cut to a fixed length, and the fixed-length cut tubular member is fed to the heating device 3 by the feeding roll 16 to heat the diffusion metal. Then, cool the diffusion metal heated by the cooling device 4,
It can also be configured to solidify. In the embodiment according to FIG. 6, a multi-winding metal pipe manufacturing apparatus according to the present invention, which is provided with a plurality of pipe bodies, which are formed at high speed and efficiently and are cut to a predetermined length by using the conventional multi-winding pipe forming apparatus, is used in large quantities. Since it can be produced, it is possible to significantly improve productivity.

Further, in each of the above-mentioned embodiments, after the diffused metal is able to diffuse into the base material of the tubular body 12 and is below the melting point, the tubular body pressing roll 7 and the pinch roll 8 exert a tensile force on the tubular body in the axial direction of the tubular body. Although the example in which the wall of the multi-winding tubular body is pressed against the wall in the radial direction is shown by the above, the tubular body pressing roll 7 is arranged at a position before heating the tubular body 11 as shown in FIG. It is also possible to provide a pinch roll 8 at a position where the diffusion metal can be diffused into the tube body and has a temperature below the melting point so that the pinch roll 8 is brought into contact with the tube body. That is, as shown in FIG. 7, the tubular body pressing roll 7 is provided on the upstream side of the high frequency heating coil 13, while the pinch roll 8 is provided on the downstream side of the coil.
Place. Therefore, the diffusion metal is in a substantially solid state when passing through the tube body pressing roll, but can pass through the high-frequency heating coil 13 to diffuse into the base material of the tube body 12 and become a state below the melting point so that the pinch roll 8 exerts a tensile force. Will be granted. In this way, when the diffused metal is diffusible in the tubular body and is below the melting point, it is important to contact at least the pinch roll 8.

[0030]

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) Even if a gap is created between the multiple winding walls due to wear of the forming tool in the forming device, variations in the mechanical properties and dimensions of the hoop material in the multiple winding forming process, peeling between the inner and outer seam portions is prevented. (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 molding is released by heating, or because the walls are pressed against each other again while releasing the residual stress, the mechanical properties such as springback and the variation of each dimension of the hoop material are taken into consideration. It is not necessary to select the material, 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 three tubular body pressing rolls in the same apparatus.

FIG. 3 is a schematic view showing another embodiment of the tubular body pressure contact portion in the same apparatus.

FIG. 4 is a vertical sectional side view showing a die as a tubular body pressing means in the same apparatus.

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

FIG. 6 is a schematic view showing a main part of another embodiment of the device of the present invention.

FIG. 7 is a schematic view showing a main part of still another embodiment of the device of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Multiple winding forming apparatus 2 Roll for transferring tube 3 Heating device 4 Cooling device 5 Energizing roll (rotating electrode) 6 DC power source 7 Tube holding roll 8 Pinch roll 9 Refrigerant injection nozzle 10 Hoop material 11 Multiple winding tube 12 Holding roll 13 high-frequency heating coil 14 guide roll 15 die 16 feed roll

Claims (9)

[Claims] 1. A transfer speed of a pipe when at least the outer peripheral side of the diffusion metal between the walls of the pipe which is formed into multiple turns and is transferred is at a temperature below the melting point capable of diffusing into the pipe body by heating. By applying a tensile force in the tube axis direction to the tube body while changing the temperature of the tube body to press the walls in a radial direction with each other and diffusing the diffusion metal in the tube body, and then cooling. Manufacturing method of metal tube. 2. The diffusible metal in the diffusible state and below the melting point is cooled to a temperature lower than the diffusible temperature of the diffusive metal by cooling that is performed at the same time or as soon as possible when the diffusive metal is pressed into the radial direction and diffused. The method for manufacturing a multi-winding metal tube according to claim 1, wherein. 3. The multiple winding according to claim 1, wherein the outer peripheral surface of the tubular body is further pressed substantially uniformly from the outer side in the radial direction at least immediately before or after the pulling in the axial direction of the tube. Manufacturing method of metal tube. 4. A molding device for molding a hoop material having a diffusion metal applied on at least one surface 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 a multi-winding metal pipe manufacturing apparatus equipped with a cooling device for cooling the heated diffusion metal and a means for transferring the pipe to the heating device and the cooling device, the diffusion metal is capable of diffusing into the pipe body. And a temperature lower than the melting point, the transfer speed varying means of the transfer device is provided in the heating device so that the pipe is pulled in the pipe axial direction and the walls are pressed against each other in the radial direction. Multi-winding metal pipe manufacturing equipment. 5. The transfer speed varying means comprises one or more sets of tube pressing rolls and one set of pinch rolls arranged on the downstream side of the pressing rolls. 5. The apparatus for producing a multi-winding metal tube according to claim 4, wherein means for increasing the diameter or increasing the rotation speed is used. 6. The manufacturing apparatus for a multi-winding tube according to claim 5, wherein said one set of tube body pressing rolls or pinch rolls has a three-piece construction. 7. The apparatus for manufacturing a multiple winding tube according to claim 5, wherein the curvature of the groove of the tubular body pressing roll is equal to or slightly smaller than the curvature of the outer diameter of the multiple winding tubular body. 8. The multi-winding tube according to claim 5, further comprising a pressing means for pressing the multi-winding tube substantially uniformly from the outside of the multi-winding tube body at least immediately before or after the transfer speed varying means. Manufacturing equipment. 9. The manufacturing apparatus for a multi-winding tube according to claim 8, wherein the pressing means comprises one or more sets of pressing rolls or dies.