JPH09136128A - Stock for manufacturing heat transfer tube having inner circumferential groove and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stock for manufacturing a heat transfer tube having inner circumferential grooves and its manufacture method capable of preventing generation of collapse in manufacturing the heat transfer tube. SOLUTION: A stock 10 for manufacturing a heat transfer tube having inner circumferential grooves is provided with a metallic bar of fixed width, a non- form rolled part 18 formed on each end part in the width direction of one side of the metallic bar, and a large number of fins 12 formed in a fin forming region between the non-form rolled parts 18. The width Q1 of the non-form rolled part is 1-10% of the width of the bar, and the thickness t1 of the non- form rolled part 18 at each end of the bar is 102-146% of the thickness t0 at the center of the bar, and the thickness t2 of the non-form rolled part at the boundary with the fin forming region is 101-141% of the thickness t0 at the center of the bar.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a material for manufacturing an inner grooved heat transfer tube and a method for manufacturing an inner grooved heat transfer tube using the material.

[0002]

2. Description of the Related Art Inner grooved heat transfer tubes are mainly used as evaporation tubes or condensation tubes in heat exchangers such as air conditioners and refrigerators, and recently, spiral grooves are formed on the entire inner surface. A heat transfer tube having a spiral fin formed between the grooves by forming the heat transfer tube is widely commercially available.

The heat transfer tube, which is currently the mainstream, is a metal tube obtained by passing a floating plug having a spiral groove formed on the outer peripheral surface inside a seamless (seamless) tube obtained by drawing or extruding. It is manufactured by a method of rolling a spiral groove over the entire inner peripheral surface of the fin.However, this manufacturing method limits the shape and height of the fin due to the characteristics of the floating plug. There is a limit to improving the heat transfer efficiency by improving the heat transfer efficiency.

Therefore, the inventors of the present invention, instead of the seamless tube, roll the long metal plate material in the width direction and weld the abutted side edges to obtain a metal tube "Electrical resistance pipe method". We are considering to use in the production of heat transfer tubes. This is because, according to the electric resistance welded pipe method, the fins to be formed on the inner surface of the heat transfer tube can be rolled in the state of the flat metal sheet material, and the degree of freedom in designing the fin shape is high.

[0005]

FIG. 10 is an enlarged cross-sectional view showing an example of a material used in a method for manufacturing a heat transfer tube with an inner groove by an electric resistance welded pipe method. This raw material 1 for producing a heat transfer tube with an inner surface groove is obtained by rolling a long plate material having a constant width and made of copper or a copper alloy with a pair of fin forming rolls.
A pair of non-rolling portions 4 are formed on both ends of one surface of the strip material in the width direction, and a large number of fins 2 are provided between the non-rolling portions 4.
The groove portions 3 are formed between the fins 2.

Incidentally, the non-rolled portion 4 shown in FIG. 10 is conventionally formed so as to have a wall thickness equal to that of the spiral groove 3. This is because it was considered preferable that the thickness of the heat transfer tube was uniform over the entire circumference. For example, in the method for manufacturing the heat transfer tube with inner groove according to Japanese Patent Application No. 2-332659 previously filed by the present applicant, the thickness of the unrolled portion of the material is made equal to the tube wall thickness in the spiral groove. It is intended for.

Next, the raw material 1 is passed through a number of forming rolls to be rounded with the fin forming surface inside, and both side edges of the strip material are abutted and welded to each other to form an inner surface as shown in FIG. The grooved heat transfer tube 5 is manufactured. At this time, if the molding conditions and welding conditions are not appropriate, the welded portion 6 may protrude toward the inner peripheral side of the tube, and a depression 7 may occur on the outer peripheral surface of the heat transfer tube 5. It was If such a depression 7 occurs, a gap is not formed when the heat radiation fins are fixed to the outer circumference of the heat transfer tube 5, which is not preferable, and the reliability of the strength of the welded portion 6 decreases. Therefore, the occurrence of the depression 7 should be avoided as much as possible.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a material for manufacturing a heat transfer tube with an inner surface groove and a method for manufacturing the heat transfer tube with an inner surface groove, which can prevent a depression from occurring during the manufacture of the heat transfer tube. It is an issue.

[0009]

In order to solve the above problems, a material for manufacturing a heat transfer tube with an inner groove according to the present invention is a metal strip material having a constant width, and a width of one surface of the strip material. A pair of non-rolling parts having a constant width formed at both ends in the direction,
And a large number of fins formed in a fin forming region between these unrolled portions, and the width of the unrolled portion is 1 to 10% of the width of the sheet material, and The thickness of the non-rolled portion on both edges of the strip is 102 to 146% of the thickness not including fins in the central portion of the strip, and the non-rolled portion at the boundary with the fin formation region. The thickness of the manufacturing part is 101 to 141 which is the thickness not including the fin in the central part of the plate material.
It is characterized by being set to%.

On the other hand, according to the method of manufacturing the heat transfer tube with the inner surface groove of the present invention, the width of one surface of the sheet material is made by passing the sheet material made of metal through at least a pair of fin forming rolls. A pair of unrolled portions having a width of 1 to 10% of the width of the strip material is formed at both ends in the direction, and a large number of fins are formed in a fin formation region between these unrolled portions, The width of the non-rolled portion is set to 2 to 20% of the width of the strip material, and the thickness of the non-rolled portion at both edges of the strip material in the central portion of the strip material is 1 thickness without fins
A fin forming step of making the thickness of the non-rolled portion at the boundary with the fin forming region 101 to 141% of the thickness not including the fin at the central portion of the plate material. The sheet material on which the fins are formed is passed through a plurality of forming rolls to form a tube so that the fins are located on the inner peripheral side, and a tube forming step is performed to form both end edges of the sheet material formed in the tube shape. And a welding step of butt-welding after heating.

[0011]

1 and 2 are a sectional view and a plan view showing a tenth embodiment of a material for producing a heat transfer tube with an inner surface groove according to the present invention. This raw material 10 includes a pair of non-rolling parts 18 having a constant width from both ends in the width direction of the one surface of a metal plate material having a constant width, and a space between these non-rolling parts 18. A large number of fins 12 arranged parallel to each other in the fin formation region and a ridge 16 extending along the boundary line between the non-rolled portion 18 and the fin formation region are formed. A spiral groove 14 is provided between the fins 12.
Are formed.

The width W1 of the non-rolling portion 18 is set to 1 to 10% of the width of the material 10, and more preferably 1.5 to 7.0.
%. When the width W1 of the non-rolled portion 18 is less than 1% or more than 10% of the width of the material 10, it is difficult to prevent the occurrence of a depression and it becomes difficult to weld both side edges of the material 10.

As shown in FIG. 1, the thickness of the non-rolled portion 18 is formed so as to gradually increase from the boundary with the fin forming region, that is, the boundary with the welded portion 22 toward each edge of the material 10. The thickness t1 of the non-rolled portion 18 at both end edges of the material 10 is 102 to 146% of the thickness t0 at the center of the material 10 not including the fins 12, and is equal to the fin formation region. The thickness t2 of the non-rolled portion 18 at the boundary of
101 of thickness t0 not including fins 12 at the center of
It is set at 141%. That is, when these relationships are expressed as a ratio, they are as follows. t1: t2: t0 = 1.02 to 1.46: 1.01 to
1.41: 1 The following equation shows only the relationship between t1 and t2. t1: t2 = 1.00 to 1.10: 1

If the thickness t1 is less than 102% of the thickness t0,
It is not possible to prevent the outer peripheral surface of the heat transfer tube after welding from dropping, and if the thickness t1 is greater than 146% of the thickness t0, the protruding material of the welded part generated in the manufactured heat transfer tube becomes too large, When fixing the radiating fins to the outer circumference of the heat transfer tube, the pipe expansion plug may be galled at the weld. A more preferable range is that the thickness t1 is 106 to 132% of the thickness t0.
It is.

When the thickness t2 is less than 101% of the thickness t0,
In the process of rolling the material 10 into a tubular shape, the relatively thick unrolled portion 18 is likely to be bent from the boundary with the welded portion 22, and there is a possibility that welding failure may occur due to the bending. On the other hand, if the thickness t2 is greater than 141% of the thickness t0, it becomes difficult to roll the material 10 into a tubular shape. A more preferable range is 105 to 128 in which the thickness t1 is the thickness t0.
%.

In order to satisfy the above relation, in this embodiment, the material thickness in the groove portion 14 between the fins 12 is different from that of the welded portion 22 from a position separated from the edge of the material 10 by a certain distance W2. It is formed to gradually increase toward the boundary. Further, in the remaining region except the region of the distance W2 from both side edges of the material 10, the material thickness in the groove portion 14 is constant within the range of variation. The distance W2 is
The width is preferably 10 to 30% of the width of the material 10, and more preferably 15 to 25%.

In this way, with the structure in which the thickness gradually increases from the both end edges of the material 10 within the range of the constant distance W2, it is easy to roll the material 10 into a perfect tubular shape while preventing the material from falling. The advantage is obtained. When the distance W2 is less than 10% of the width of the material 10, the non-rolled portion 18 becomes the material 1
It easily bends when rounding 0, while the distance W2
Is more than 30% of the width of the raw material 10, the average thickness of the heat transfer tube becomes unnecessarily large, and the heat exchange performance deteriorates accordingly, which is not preferable.

As shown in FIG. 2, the fin 12 of this embodiment is formed so as to intersect the longitudinal direction of the material 10 at a constant angle (spiral angle) α. This allows
The manufactured heat transfer tube has a spiral shape around the tube axis. The spiral angle α is a value determined according to the characteristics required for the heat transfer tube, and is not particularly limited in the present invention, but is preferably 10 to 25 °, more preferably 15 to 20 °.

Further, in this embodiment, as shown in FIG. 2, both ends of each fin 12 are connected to the ridges 16, respectively. By forming the ridges 16 in this manner and further connecting the ends of the fins 12 to the ridges 16, when the fins 12 are rolled on the plate material B, both end edges of the plate material B are rolled. It is possible to obtain the effect that the wavy deformation is less likely to occur. However, in the present invention, it is also possible to implement a configuration in which the ends of the fins 12 are not connected to the ridges 16.

As shown in FIG. 3, the height H from the inner surface of the metal pipe of the portion of the fin 12 located within a certain distance W2 from both side edges of the material gradually decreases as it approaches the ridge 16. The ridge line of the fin 12 is continuous with the ridge line of the ridge portion 16 at substantially the same height as shown in FIG. ing.

The amount of protrusion of the protrusion 16 from the inner surface of the metal pipe is
The amount of protrusion of the fin 12 at the center of the material 10 is 10
It is preferably 80%, more preferably 15 to 7
It is set to 0%. If it is 10 to 80%, the ridge 16 is less likely to hit the pipe expansion plug during pipe expansion, and the ridge 16
The reinforcing effect can be sufficiently obtained.

Next, FIG. 3 shows a heat transfer tube 10 having the above structure.
It is a side view showing an example of the manufacturing apparatus of. In the figure, reference numeral 30 is an uncoiler that continuously feeds a metal strip material B having a constant width, and the fed strip material B is a pair of pressing rolls 3.
2 through, paired grooved roll 34 and smooth roll 3
6 (both collectively referred to as fin forming rolls),
By the grooved roll 34, the non-rolled portion 18, the fin 12 and the spiral groove 14 shown in FIGS. 1 and 2 are formed. In this embodiment, the fins 12 and the like are formed only on the front surface S1 of the strip material B, and the back surface S2 is kept smooth.

4 to 6 are detailed views of the grooved roll 34 and the smooth roll 36. These rolls 34 and 36 are rotatably supported by the frame 58 via shafts 54 and 56, respectively. As shown in FIGS. 5 and 6, the grooved roll 34 includes a grooved roll main body 34A having rolling grooves 62 formed on the outer peripheral surface thereof, and a pair of side rolls 34B fixed to both sides thereof. There is. The fins 12 are formed on the plate material B by the rolling grooves 62 of the grooved roll main body 34A, and the spiral grooves 14 are formed by the protrusions 64 between the rolling grooves 62.
Meanwhile, the non-rolled portion 18 is formed by the side rolls 34B.

The outer peripheral surface of the central portion of the grooved roll main body 34A (the end surface of the protrusion 64) is an accurate cylindrical surface. On the other hand, the outer peripheral surfaces (the tip surfaces of the protrusions 64) of the grooved roll main body 34A on both sides in the axial direction are conical surfaces whose outer diameter gradually decreases toward the side roll 34B side. As a result, as shown in FIG. 6, the thickness of the strip material B within the width W2 from the side edge of the material 10 is formed so as to gradually increase toward the protruding portion 16. In addition, the depths of the rolling grooves 62 are formed on both sides of the grooved roll main body 34A in the axial direction such that the depth gradually decreases toward both ends of the grooved roll main body 34A. This makes material 1
The height of the fin 12 formed at 0 is formed so as to decrease as it approaches the ridge portion 16.

The outer peripheral surface of the side roll 34B is a taper surface whose outer diameter decreases toward the outer side in the axial direction, and this outer peripheral surface increases the thickness of the raw material 10 toward the side edges of the unrolled portion 1.
8 is formed. The unrolled portion 18
May be formed in a state of being slightly curved toward the fin formation surface side. This is because such curving may occur, and even if such curving occurs, there is no problem in electric resistance sewing.

Grooved roll body 34A and side rolls 34
At the boundary with B, a ridge portion forming groove 60 extending over the entire circumference of the outer peripheral surface is formed, and the ridge portion forming groove 60 allows the raw material 10 to be fixed from both side edges thereof. A ridge portion 16 extending in the longitudinal direction of the plate material B is formed over the entire length at positions separated by a distance. In addition, in this embodiment, the cross-sectional shape of the ridge portion forming groove 60 is a gentle arc shape, but it may be a triangular shape in cross section.

The sheet material B grooved by the grooved rolls 34 and the smooth rolls 36 is gradually rolled into a tubular shape through a pair of rolls 38 and a plurality of forming rolls 40 arranged as shown in FIG. The rolling separator 41 keeps a constant gap between the opposite edges to be abutted, and then the induction heating coil 42 is passed through to heat both side edges. The plate material B formed into a tubular shape and heated is passed through a pair of squeeze rolls 44 and pressed from both sides so that the heated both side edges are abutted and welded. A bead cutter 46 for cutting the bead is provided on the outer peripheral surface of the heat transfer tube 10 welded in this way, because a bead is formed by the molten material protruding.

The heat transfer tube 10 with the bead cut is a cooling tank 4
After passing through 8 to be forcibly cooled, a plurality of pairs of sizing rolls 50 are passed through and the diameter is reduced to a predetermined outer diameter. Further, the heat transfer tube 10 having a reduced diameter
Is taken up by the rough coiler 52.

Next, an embodiment of a method of manufacturing a heat transfer tube with an inner groove using the above apparatus will be described. In the method of this embodiment, first, the strip material B having a constant width is continuously fed from the uncoiler 30, and the strip material B fed is passed between the grooved roll 34 and the receiving roll 36 via the pair of pressing rolls 32. The fins 12, the spiral grooves 14, the ridges 16, and the non-rolled portion 18 are formed through the gap and by the grooved roll 34 as shown in FIGS. 1 and 2.

As the material of the strip material B, any material can be used as long as it is copper or a copper alloy. Not only deoxidized copper (eg JIS 1220 alloy) which is generally used as a material for heat transfer tubes, but also oxygen-free copper. The same effect can be obtained when applied to copper alloy, aluminum, aluminum alloy, steel and the like.

In the present invention, the general outer diameter is 3 to 15 mm.
When applied to the production of a heat transfer tube of a certain degree, it is preferable that the thickness of the strip material B before groove formation is 0.3 to 1.2 mm, and the maximum of the spiral groove 14 formed in the strip material B. Depth (=
The maximum height of the fin 12) is 30 to 60 of the thickness of the plate material B.
%. When the height of the fins 12 is made higher than that of the conventional product, the drainage property of the fins 12 and the effect of generating turbulence are improved, and high heat exchange performance that cannot be obtained by the conventional seamless pipe is obtained.

Next, the grooved plate material B is applied to a pair of rolls 38 and a plurality of pairs of forming rolls 40.
Then, the rolling separator 41 is gradually rolled into a tubular shape, and the rolling separator 41 keeps a constant distance (gap amount) between the opposite edges. Then, it is passed through the induction heating coil 42 to heat both side edges, and the pair of squeeze rolls 4
By pushing from both sides through 4, both side edges are butted and welded. Since the molten material protruding to the outer peripheral surface of the heat transfer tube 10 becomes a bead, this bead is used as the bead cutter 4.
Cut with 6.

The heat transfer tube 10 with the bead cut is placed in the cooling tank 4.
8 through forcible cooling, and a plurality of pairs of sizing rolls 50 are passed through to reduce the diameter to a predetermined outer diameter. The heat transfer tube 20 thus reduced in diameter is wound by the rough coiler 52. However, this step is a case where the apparatus of FIG. 4 is used, and it goes without saying that it may be changed according to the configuration of the apparatus.

FIGS. 7 and 8 are a sectional view and a developed view of the inner surface showing an example of the inner surface grooved heat transfer tube 20 thus obtained. Non-rolling part 1 formed on both side edges of the material 10.
8 are butted against each other and welded to form a welded portion 22 that slightly protrudes inward, and groove portions 24 parallel to the welded portion 22 are formed on both sides thereof.

The welded portion 2 at the top of the welded portion 22
It is desirable that the thickness of the metal tube including the height of 2 is slightly smaller than the thickness of the metal tube including the height of the fin 12 at the portion having no taper. If the tip of the welded portion 22 projects inward from the fins 12, there is a risk of galling between the welded portion 22 and the pipe expanding plug when expanding the pipe to fix the heat radiation fins to the outer periphery of the heat transfer tube 10. is there. Further, if the tip of the welded portion 22 is located far outside the fins 12, a dent is formed on the outer peripheral surface of the pipe at the position corresponding to the welded portion 22 during the pipe expanding process, and the cylindricity of the heat transfer tube 20 is reduced. Then, the radiation fins may not be fixed sufficiently.

According to the material 10 for manufacturing a heat transfer tube with an inner surface groove and the method for manufacturing a heat transfer tube having the above-described structure, the thickness of the non-rolled portion 18 formed on both side edge portions and the vicinity thereof is determined by the material side edge. Since the forming roll 40 is formed in a tubular shape and the squeeze roll 44 abuts both side edges of the tube, even if some variation occurs in the electric sewing conditions, the both sides are formed. The edges do not bend excessively inward, and the outer peripheral surface of the manufactured heat transfer tube is unlikely to drop.

Therefore, it is possible to alleviate the problems such as the mounting of the radiation fins due to the depression and the galvanization of the manufactured heat transfer tube 20 when the expanded tube is welded and galling. It is possible to improve reliability in manufacturing.

Further, since the ridges 16 are formed at the boundary between the non-rolling portion 18 and the fin forming region, the effect of reinforcing these boundary portions can be obtained, and the non-rolling portion 18 bends from the boundary. Can be prevented. Therefore, also from this point, it is possible to obtain the effect of preventing the heat transfer tube from dropping.

When rolling the fin 12 and the spiral groove 14 on the plate material B, the non-rolled portion 1 is formed from the end of the spiral groove 14.
Even if a material flow occurs toward 8, the ridge portion 1 formed between the spiral groove 14 and the non-rolling portion 18 is formed by this material flow.
6, it is possible to prevent the formation of a wavy shape at the edge of the strip material B by blocking. Therefore, it is possible to prevent defects in the welded portion 22 caused by the generation of the corrugated shape, and also from this point, the reliability of the heat transfer tube 10 with the inner groove can be improved.

In the above embodiment, the ridges 16 are formed on both sides of the material 10, but the ridges 16 are not formed as shown in FIG. 9, and the distance W1 from the side edge of the material 10 is reduced. A structure in which the fins 12 extend to the respective positions is also possible. Further, in the above-described embodiment, the grooved roll 34
Although only one stage of fin rolling was performed by, the rolling was performed in two or more stages by using two or more grooved rolls, and the second rolling was performed on the fin formed by the first rolling. It is also possible to form a groove that intersects with the fin.

Further, although the fin 12 has a simple spiral shape in the above-mentioned embodiment, it is possible to form a fin other than the spiral shape in the present invention. For example, fins having a V shape or a W shape in plan view may be formed side by side in the circumferential direction. According to such a V-shaped fin 12,
The effect of making the heat medium flowing in the heat transfer tube turbulent becomes stronger, and the heat exchange efficiency can be improved. Of course, the planar shape of the fin is not limited to the V-shape or the W-shape, but various modifications such as a C-shape are possible.

Further, in the present invention, it is possible to implement a structure in which a large number of short fins divided in the longitudinal direction are formed in a zigzag shape or a spiral shape, and in any case, the excellent effect described above can be obtained. Furthermore, instead of forming the fins and the spiral grooves only on the inner surface of the heat transfer tube, the fins and grooves may be formed on the outer surface of the heat transfer tube.

[0043]

EXAMPLES Next, the effects of the present invention will be demonstrated with reference to examples. 1 shows a case where an inner grooved heat transfer tube is manufactured by using the grooved roll 34 having the cross-sectional shape shown in FIG.
As shown in 0, when the thickness of the non-rolled portion 4 is equal to the thickness not including fins in the fin formation region (comparative example), heat transfer tubes are manufactured and the heat transfer tubes are formed on the outer peripheral surface thereof. It was inspected whether a depression occurred. All conditions were common except the conditions for rolling fins.

Fin rolling conditions are as follows. [Common conditions] Initial thickness of strip B: 0.44 mm Material of strip B: Phosphorous deoxidized copper Maximum height of fin 12: 0.20 mm Pitch of fin 12: 0.44 mm Both sides of fin 12 Angle (vertical angle): 53 °

[Example] Thickness t0 at the center of the material 10: 0.30 mm Thickness t1: 0.37 mm at the end of the unrolled portion 18 = 123% of t0 Boundary with the ridge portion 16 Thickness t2 of the non-rolled portion 18 of: 0.3
6mm = 120% of t0 Width W1: 2.10 mm of non-rolled portion 18 Width W2 of the taper portion: 7.10 mm

[Comparative Example] Thickness t0 at the central part of the material 10: 0.30 mm Thickness t1: 0.30 mm at the end of the unrolled part 18 = 100% of t0 Boundary with the ridge 16. Thickness t2 of the non-rolled portion 18 of: 0.3
0 mm = 100% of t0 Width W1: 2.10 mm of the unrolled portion 18

When the heat transfer tube was manufactured 6 times under the above conditions, the heat transfer tube obtained by the method of the example did not cause any depression, whereas the method of the comparative example produced the heat transfer tube by 6 times. The outer peripheral surface of the was depressed.

[0048]

As described above, according to the material for manufacturing a heat transfer tube with an inner surface groove and the method for manufacturing a heat transfer tube with an inner surface groove according to the present invention, a non-rolled portion formed on both side edges of the material and the same Since the thickness of the vicinity part is formed so as to increase toward the side edge of the material by a predetermined ratio, when the material is formed into a tubular shape and both edges are abutted, there will be some variation in the electric sewing conditions. Even if it occurs, both side edges are less likely to be bent inward excessively, and the outer peripheral surface of the manufactured heat transfer tube is unlikely to drop. Therefore, it is possible to mitigate problems such as abnormal mounting of the heat dissipation fins due to the depression, and problems such as galling of the welded portion with the expansion plug when expanding the manufactured heat transfer tube, thus improving the reliability of the heat transfer tube with inner groove. It is possible to improve.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a material for producing a heat transfer tube with an inner groove according to the present invention.

FIG. 2 is a plan view of the same material for manufacturing a heat transfer tube with an inner groove.

FIG. 3 is a side view showing an example of a manufacturing apparatus used in the method for manufacturing a heat transfer tube with an inner groove according to the present invention.

FIG. 4 is a side view showing a fin forming roll of the manufacturing apparatus.

FIG. 5 is a front view of the fin forming roll.

FIG. 6 is an enlarged cross-sectional view of a state in which fins and the like are rolled on a plate material by the fin forming roll.

FIG. 7 is a cross-sectional view showing an example of an inner grooved heat transfer tube manufactured by the method of the same embodiment.

FIG. 8 is a development view of the inner surface of the heat transfer tube with the inner surface groove.

FIG. 9 is a cross-sectional view showing another embodiment of a material for manufacturing a heat transfer tube with an inner groove according to the present invention.

FIG. 10 is a cross-sectional view showing a conventional material for manufacturing a heat transfer tube with an inner groove.

FIG. 11 is an enlarged cross-sectional view showing a problem of a conventional material for manufacturing a heat transfer tube with an inner groove.

[Explanation of symbols]

 10 Material for manufacturing heat transfer tube with inner groove 12 Fin 14 Spiral groove 16 Ridge portion 18 Rollless portion W1 Width of unrolled portion W2 Width of region where material thickness is tapered t0 None in the center of material Thickness of rolled part t1 Thickness of unrolled part at side edge of material t2 Thickness of unrolled part at boundary with fin forming region 20 Heat transfer tube with internal groove 22 Welded portion B Plate strip 34 With groove Roll (fin forming roll) 36 Receiving roll (fin forming roll) 40 Forming roll 42 Induction heating coil 62 Rolling groove 64 Ridge portion

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshikatsu Arayama 128-7 Ogimachi, Aizuwakamatsu, Fukushima Prefecture 7-8 Mitsubishi Shindoh Co., Ltd. Wakamatsu Manufacturing (72) Inventor Kotaro Nagahara 128-7, Ogimachi, Aizuwakamatsu, Fukushima Prefecture Mitsubishi Shin Copper Wakamatsu Manufacturing Co., Ltd. (72) Inventor ▲ Sukumo ▼ Shun Tad ▲ Green ▼ 128-7 Ogimachi, Aizuwakamatsu City, Fukushima Prefecture Mitsubishi Shindoh Co., Ltd. Wakamatsu Manufacturing Co., Ltd.

Claims (4)

[Claims] 1. A metal strip material having a constant width, a pair of non-rolled portions having a constant width formed at both widthwise ends of one surface of the strip material, and these non-rolled portions. An inner surface grooved heat transfer tube manufacturing material comprising a large number of fins formed in the fin formation region between, wherein the width of the unrolled portion is 1 to 10% of the width of the plate material. At the same time, the thickness of the non-rolled portion at both edges of the plate material is 1 at a thickness not including fins at the central portion of the plate material.
02-146%, and the thickness of the non-rolled portion at the boundary with the fin formation region is 101-141% of the thickness not including fins in the central portion of the strip material. Material for manufacturing heat transfer tubes with internal grooves. 2. A pair of ridges is formed on one surface of the plate material along a boundary between the fin forming region and each unrolled portion. Material for manufacturing heat transfer tube with inner groove as described. 3. The inner grooved transmission according to claim 1, wherein the height of the fin from one surface of the plate member is decreased as it approaches the both end edges. Material for manufacturing heat tubes. 4. A sheet material made of metal is passed through at least a pair of fin-forming rolls while the sheet material is running, so that the width of the sheet material is 1 to 10 at both end portions in the width direction of one surface of the sheet material.
% Of the non-rolled portion and a large number of fins are formed in the fin forming region between the non-rolled portions, and the width of the non-rolled portion is set to the width of the plate material. 2 to 2
0%, and the thickness of the non-rolled portion at both edges of the strip is 102-146% of the thickness not including fins in the central portion of the strip, and the fin forming region The fin forming step of making the thickness of the non-rolled portion at the boundary of 101 to 141% of the thickness not including the fin in the central portion of the plate material, and the plate material on which the fin is formed. A tube forming step of forming a tubular shape so that the fins are located on the inner peripheral side through a plurality of forming rolls, and a welding step of heating both end edges of the tubular sheet material and then welding them by abutting. A method for manufacturing a heat transfer tube with an inner groove, comprising: