KR20130127431A - Internally grooved aluminum alloy heat transfer pipe - Google Patents

Abstract

It is related with the heat exchanger tube which a pin crush is hard to generate | occur | produce, excellent in corrosion resistance, and thinning.
A plurality of protruding fins are formed on the inner surface, Mn: 0.8-1.8 mass% (hereinafter referred to as% by mass), Mg: 0.1-0.6%, and the balance is made of Al and unavoidable impurities. It provides a heat transfer pipe having an inner groove made of an aluminum alloy.

Description

Heat pipe with inner groove made of aluminum alloy {INTERNALLY GROOVED ALUMINUM ALLOY HEAT TRANSFER PIPE}

The present invention relates to a heat transfer tube having an inner groove made of aluminum, which is used as a heat transfer tube of a cross fin type heat exchanger that can be employed in a domestic air conditioner, a commercial air conditioner, a heat pump type water heater, and the like.

The heat exchanger (FIG. 1) of the general cross fin (also called fin and tube type) inserts a heat exchanger tube into the insertion hole opened to the aluminum heat radiating fin, and then expands a mandrel for expansion which has an outer diameter larger than the inner diameter inside the heat transfer tube. Insert a (mandrel) to expand the diameter of the heat transfer pipe, and closely contact the outer circumferential surface of the heat transfer tube with the insertion hole of the aluminum heat dissipation fin (expansion processing. Fig. 2). Thereafter, the heat transfer tube integrated with the aluminum heat dissipation fin is bent into a hairpin shape, and the heat transfer tube (U-shaped tube), which is separately bent in a U-shape, is joined by torch soldering (non-patent document 1).

The heat transfer tube used in the cross fin type heat exchanger is a heat transfer tube made of copper having a projecting fin having a trapezoidal or triangular cross section on the inner surface of the heat exchanger by flowing HFC or the like as a refrigerant in the tube. The method of increasing the efficiency of the heat exchanger and saving energy is being promoted by using a pipe having a diameter of the heat exchanger, and the depth of the grooves between the protrusion fins, the bottom thickness (the thickness of the base of the protrusion fin), and the fin Various heat transfer tubes which define the shape (vertical angle etc.) or the lead angle (arrangement angle of the pin with respect to the tube longitudinal direction) of the projection fin shown in FIG. 5 are proposed (for example, patent document 1). It is said that the heat transfer performance of a tube having an inner groove is excellent because the surface area inside the tube is increased compared to the smooth tube, and a uniform coolant liquid film is formed in the tube by the groove (non-patent). Document 2).

In the pipe | tube inner surface of the pipe | tube which has an inner surface groove | channel, generally, the projection pin arrange | positioned continuously in a spiral form is formed by rolling a smooth pipe. As a roll processing method, a plug having a groove that is freely rotated is inserted into a pipe, and a roll rolling method (see FIG. 3) which pulls out a pipe while pressing and rotating a planet freely rotated outside the pipe, or a ball pressing mechanism instead of a roll. One ball rolling method is known (nonpatent literature 1, patent document 2).

Although copper-based materials such as copper and copper alloys have been mainly used for tubes having inner grooves, aluminum-based materials such as aluminum and aluminum alloys (hereinafter referred to as aluminum alloys) in order to reduce the cost of materials and meet the demand of light weight. Is considered to be used.

However, when aluminum alloy is compared with a copper type material, corrosion resistance is anticipated to fall. Therefore, for example, in Patent Document 3, the heat transfer tube is referred to as a two-layer structure, the inner layer of the tube is made of Al-Mn-based alloy, and the outer surface layer is cladding the Al-Zn-based alloy as a sacrificial layer. The tube which has one inner groove is proposed.

Or, in patent document 4, Al-Mn type alloys, such as A3003, are used for the inner layer of a heat exchanger tube, and the outer surface layer has the inner surface groove which clad Al-Zn type alloys, such as A7072, as a sacrificial anticorrosive layer, and the said inner surface Heat exchangers using grooved tubes have been proposed.

On the other hand, in addition to the problem of corrosion resistance, when pipes having inner grooves made of these aluminum are expanded, so-called pin fin crushing occurs, in which the head part of the projection pin on the inner surface of the pipe is broken. Due to the collapse of the fin shape and insufficient adhesion to the aluminum heat dissipation fins, there is a problem that the expected heat transfer performance cannot be obtained. This is because the material strength of the tube having aluminum or aluminum alloy inner grooves is lower than that of copper.

In order to solve the pin dent at the time of expansion pipe processing, it is proposed by patent document 5 to form an oxide film with a thickness of 5 micrometers or more in the inner surface of an aluminum tube.

In addition, in Patent Document 6, the inner layer in which the protruding fin is formed is made of an aluminum alloy layer having a high mechanical strength, and an inner groove made of aluminum clad with an aluminum layer having a small mechanical strength on the outer layer of the aluminum alloy layer. Branch tubes are proposed. As a specific alloy, the example which used A3003 aluminum alloy as an inner layer and A1050 (pure aluminum) as an outer layer is shown. In this document, the outer circumferential tube bottom thickness portion made of A1050 is deformed preferentially and the outer diameter is expanded, and the inner circumferential tube bottom thickness portion made of A3003 is located on the inner surface even if expansion is performed because the deformation amount is small. It is demonstrated that the amount of crushing of the protrusion pin can be kept below the allowable range.

In addition, Patent Document 7 uses a high-strength alloy in which Zn is added to an outer layer material Al-Mn alloy (A3000 alloy) of an aluminum tube as a tube having an inner groove excellent in expansion pipe workability. Three-layer clad pipe using Al-Mg-Si alloy (A6000 alloy) or Al-Mg-based alloy (A5000 alloy) Proposed.

Japanese Patent Application Laid-Open No. 2003-287383 Japanese Patent Application Laid-Open No. 4-262818 Japanese Patent Application Laid-Open No. 2000-121270 Japanese Patent Publication No. 2009-250562 Japanese Patent Application Laid-Open No. 2000-205782 Japanese Patent Application Laid-Open No. 11-351791 Japanese Patent Application Laid-Open No. 2008-266738

Masaaki Ito: Heat, 42, 174 (2003), 3 Akio Isozaki Others: R & D Kobe Steel Making Announcement 50, 3 (2000), 66

However, the prior art described in the above documents has room for improvement in the following points.

First, in Patent Literature 1, Patent Literature 2, Non-Patent Literature 1, and Non-Patent Literature 2, problems of corrosion and pin crushing when the aluminum alloy was used in the heat transfer tube were not improved.

Second, Patent Document 3 and Patent Document 4 describe a method for improving the corrosion resistance of the heat transfer tube, but the pin crushing problem has not been improved.

Third, although patent document 5-patent document 7 describes the method for improving the fin crush of a heat exchanger tube, it has room for improvement at the following points. In other words, in Patent Document 5, in order to add anodizing treatment or the like as a step of forming an oxide film therein, a significant improvement in processing cost is invited, which is not practical. It is also very difficult to perform such a treatment on the inside of a generally long pipe.

In patent document 6, it is necessary to make thickness ratio of pure aluminum of an outer layer thicker than A3003 alloy of an inner layer. In the two examples disclosed in the embodiment of the document, the A3003 inner layer is 0.2 mm for the A1050 outer layer 0.8 mm, or the A3003 inner layer is 0.3 mm for the A1050 outer layer 0.7 mm, most of which are A1050. It is. However, since such structure is lowered in the strength of the tube itself, it is necessary to make the tube thicker in order to obtain a pressure resistance that withstands the internal pressure of the refrigerant, and the material cost is high and it is not economical.

In Patent Document 7, in order to use a three-layer cladding tube, the manufacturing process is complicated and the productivity and yield are also lowered, so that there is a problem that the processing cost increases.

The present invention has been made in view of the above, and an object thereof is to provide a heat transfer tube having an inner groove made of an aluminum alloy in which pin crushing is unlikely to occur even if the pipe is mechanically expanded by a mandrel. Another object of the present invention is to provide a heat exchanger tube having an inner groove made of an aluminum alloy capable of thinning, which has better corrosion resistance as a heat transfer tube that is hard to generate such pin crush.

MEANS TO SOLVE THE PROBLEM As a result of earnest examination, the present inventors discovered that the following heat exchanger solved the subject, and completed this invention.

That is, according to the present invention, a plurality of protruding fins are formed on the inner surface, and contain Mn: 0.8-1.8% by mass (hereinafter referred to as% by mass), Mg: 0.1-0.6%, and the balance is Al and A heat transfer tube having an inner groove made of an aluminum alloy characterized by inevitable impurities is provided.

According to this structure, a heat exchanger tube in which fin crushing hardly occurs can be obtained.

According to the present invention, a plurality of protruding fins are formed on the inner surface and contain Mn: 0.8-1.8%, Mg: 0.1-0.6%, and more Fe: 0.60% or less, Si: 0.60% or less and Cu: 0.30. % Or less, Zn: 0.30% or less, Cr: 0.20% or less, Ti: 0.20% or less, Zr: 0.20% or less, containing one or two or more, and the balance consists of Al and unavoidable impurities. A heat pipe having an inner groove made of an aluminum alloy is provided.

According to this structure, a heat exchanger tube in which fin crushing hardly occurs can be obtained.

Moreover, according to this invention, the heat exchanger provided with any one said heat exchanger tube is provided.

According to this structure, since the heat exchanger tube which a fin crush does not generate | occur | produce easily is provided, the heat exchanger excellent in heat transfer performance can be obtained.

Moreover, according to this invention, the air conditioner provided with any one said heat exchanger tube is provided.

According to this structure, since the heat exchanger tube which is hard to generate | occur | produce fin crushing is provided, the air conditioner excellent in heat transfer performance can be obtained.

The heat exchanger tube having an inner groove made of the aluminum alloy of the present invention has an effect that pin crushing is unlikely to occur even if the tube is mechanically expanded by a mandrel. Alternatively, pin crushing is unlikely to occur, it has good corrosion resistance, and thinning is possible, so that the material cost can be suppressed.

1 is a partially enlarged view of a cross fin type heat exchanger.
2 is a view showing a mandrel expansion method.
3 is an example of a roll rolling device.
4 is a schematic cross-sectional view of a tube having an inner groove.
It is a schematic diagram which shows the lead angle of an inner surface protruding pin.

EMBODIMENT OF THE INVENTION Below, embodiment of this invention is described in detail. In addition, about the same content, description is abbreviate | omitted suitably in order to avoid repetitive clutter.

Embodiment 1: Heat Transfer Tube

(1-1) Ingredients

The heat exchanger tube assumed in this embodiment is generally used for the heat exchanger for air conditioners for home use, The dimension is φ 4.0-φ 9.54 mm of outer diameter, 0.3- of bottom thickness, for example. It is 0.6mm in diameter and small in thickness. Therefore, among various aluminum alloys, Al-Mn system which has moderate strength and is relatively excellent in workability (extrusion property, PS property, rolling property) for obtaining a tube with a small diameter and a thin thickness. The aluminum alloy which prevents pin crushing by pipe expansion process is obtained by making the base material and raising strength, without damaging workability by element adjustment.

In the heat exchanger tube of the present embodiment, a plurality of protruding fins are formed on the inner surface, and contain Mn: 0.8-1.8% by mass (hereinafter, the% by mass), Mg: 0.1-0.6%, and the balance is Al. It is a heat transfer tube having an inner groove made of an aluminum alloy, characterized in that consisting of and unavoidable impurities. The heat transfer tube has an effect that pin crushing is unlikely to occur, as demonstrated in the examples described below. Since the heat-transfer tube has a high pressure resistance of the tube, the material cost can be reduced due to the thinning. Since the said heat exchanger tube does not necessarily require a complicated production process or a special structure, it is excellent in productivity, quality, etc.

The heat pipe, a plurality of protruding fins are formed on the inner surface, Mn: 0.8 ~ 1.8%, Mg: 0.1 ~ 0.6%, Fe: 0.60% or less, Si: 0.60% or less, Zn: 0.30% or less The inner groove made of an aluminum alloy containing at least one of Cr, 0.20% or less, Ti: 0.20% or less, Zr: 0.20% or less, and the balance consists of Al and unavoidable impurities. The branch may have the same effect even in the case of a heat transfer tube.

Here, an aluminum alloy is an alloy which has Al as a main component. Content of Al in an aluminum alloy is 90 to 99.9%, for example.

Next, the reason for component limitation of the heat exchanger tube in this embodiment is demonstrated.

Mn is a major addition element to increase the strength in the 3000-based alloy, and solid solution in aluminum, part of the precipitate precipitates to give strength, if the addition amount is less than 0.8%, the strength as a heat pipe is insufficient, If the amount is more than 1.8%, the strength-improving effect is saturated, and the amount of coarse and coarse intermetallic compound increases, so that a poor shape such as breaking in the tube manufacturing process tends to occur. Therefore, Mn addition amount is taken as 0.8 to 1.8% of range. More preferable range is 1.0 to 1.5%.

Mg is an element which is solid-dissolved in aluminum and has the effect of further improving strength, and does not impair workability. If the added amount is less than 0.1%, the strength is insufficient to prevent the groove from crushing in mechanical expansion, and if it is more than 0.6%, the extrudability and the drawing property deteriorate. Therefore, Mg addition amount is taken as 0.1 to 0.6% of range. The preferable range is still 0.2 to 0.5%.

Impurities include Fe, Si, Cu, Zn and the like, but these do not impair the effects of the present invention if Fe: 0.60% or less, Si: 0.60% or less, Cu: 0.30% or less, or Zn: 0.30% or less. It is more preferable that these content rates are small from a viewpoint which does not impair the effect of this invention. In addition, the lower limit of these content rates is not specifically limited, For example, 0.01, 0.001, 0.0001 or more, or 0% may be sufficient.

In addition, Ti, Cr, and Zr may be contained because of the effect of uniformly minimizing the ingot structure, but when it exceeds 0.2%, a large intermetallic compound is formed or the extrudability is lowered, so the content thereof is made 0.2% or less. Although the lower limit of these content rates is not specifically limited, For example, 0.01, 0.001, 0.0001 or more, or 0% may be sufficient.

(1-2) pin

In this embodiment, HV (Vickers hardness) may be 33 or more as the hardness of the protruding pin. This is to avoid pin crush in the expansion process. Specifically, in order to control the hardness, a specific process control such as the combination of the Mn and Mg addition amounts is appropriately optimized (basically, a higher combination within the component range) and not overheated during annealing. May be done. On the other hand, if the hardness of the protruding pin is HV of 33 or more before expansion, the protruding pin does not plastically deform at the time of expansion, so that the hardness after expansion is not changed to a value of HV lower than 33.

(1-3) Sacrifice anticorrosion layer

The heat transfer tube of the present embodiment is assumed to be used as a heat exchanger of an outdoor unit in a salt bath or the like on the shore, and a pure Al or Al-Zn alloy layer may be provided on the outer surface of the heat transfer tube as a sacrificial anticorrosive layer. . The heat exchanger tube of the present embodiment in which the sacrificial anticorrosive layer is formed has excellent quality on both sides of corrosion resistance and fin crushing, and thus becomes a high quality heat transfer tube.

As for the thickness of such a sacrificial anticorrosive layer, 5-30% is preferable with respect to whole thickness. If the thickness of the sacrificial anticorrosive layer is less than 5% of the total thickness, the service life of the sacrificial anticorrosive layer in use as a heat exchanger is insufficient, and if the sacrificial anticorrosive layer exceeds 30%, the strength of the heat transfer tube may be reduced, making it difficult to thin.

The component of the sacrificial anticorrosive layer may have a lower natural potential than that of the Al-Mn-Mg alloy of the core material. For example, pure aluminum such as A1050 or A7072 (Al-0.8 to 1.3% Zn alloy). Al-Zn alloys, such as), may be used as appropriate.

Next, an example of an embodiment of a method of forming a sacrificial anticorrosive layer will be described.

The combination billet which bend | folded the sacrificial-type alloy plate material (pure Al or Al-Zn type alloy) in the cylindrical shape at the outer side of the cylindrical billet of the Al-Mn-Mg type alloy in the heat exchanger tube of this embodiment was produced. This is heated to 350 to 600 ° C. in a heating furnace to perform a homogenization treatment. The combination billet is inserted between the extrusion die and the extruded ram nose and inserted into the container. In the state in which the extruded die and the extruded ram nose are fixed, a mandrel having an outer diameter larger than the core diameter is press-fitted, and the core is inserted into the container. Expand and exhale the air between the core and the shell. Next, the mandrel is fixed at a predetermined position, the extrusion hollow rod is advanced, and the combination billet is extruded through a die to obtain a two-layer clad extrusion tube. Next, the extruded tube is subjected to PS processing so as to have a predetermined outer diameter and thickness to obtain a smooth tube of a two-layer cladding. It is preferable to use the draw block type continuous drawing machine for the said drawing process with high productivity.

Alternatively, after the billet of the cylindrical sacrificial anticorrosive material is heated to 350 to 600 ° C., the two-layer hollow billet obtained by shrinkage-inserting the cylindrical core hollow billet inside is extruded, and then PS processing can be performed and the smooth pipe of a two-layer cladding can also be obtained.

In addition, a sacrificial anticorrosive material sheet is clad rolled on one side of the aluminum alloy core sheet to form a two-layer clad sheet, and the sheet is rolled into a tubular shape to weld a sheet bump surface to weld the two-layer cladding. It is good also as a sealing tube.

The above has described a method of forming a two-layer smooth tube in which a sacrificial anticorrosive layer is formed by clad extrusion, PS or clad rolling, but as another method, extrusion of Al-Mn-Mg-based alloy in the heat transfer tube of the present embodiment. After spraying Zn on a tube (by hot extrusion or conform extrusion) or a drawing tube, a method of forming an Al-Zn diffusion layer by performing Zn diffusion heating may be employed. In this case, it is preferable to set the temperature and time of a diffusion heating process suitably, and to make a Zn diffused layer into 5 to 30% of range with respect to the total thickness. It is industrially preferable that the temperature is made into about 2 to 8 hours at 400-500 degreeC in general. On the other hand, only in the case of employing the Zn spraying method, after performing the rolling process described later, the Zn spraying and the diffusion heat treatment may be performed.

On the other hand, it is preferable to perform a preliminary softening treatment in advance on the smooth pipe in which the sacrificial anticorrosive layer is formed in order to facilitate the roll processing of the next step. In that case, it is industrially preferable that annealing conditions are 300-400 degreeC, and time is about 2 to 8 hours.

In addition, the smooth pipe described above slightly decreases in outer diameter and thickness in the rolling process of the next step. Therefore, the size (outer diameter, thickness) of the smooth pipe is set larger than the pipe having the inner groove as the final product in consideration of the reduced portion.

Next, the smooth pipe is rolled by roll rolling, ball rolling, or the like to produce a pipe having an inner groove having a protruding pin.

(1-4) Structure and processing method

The pipe having the inner groove of the present embodiment can be manufactured in various dimensions depending on the use of the heat exchanger. However, when used in a domestic air conditioner, an outer diameter φ 4.0 mm or more is preferable from the viewpoint of productivity in manufacturing the pipe. From the viewpoint of miniaturization and weight reduction of the heat exchanger, the outer diameter? 9.54 mm or less is preferable.

In terms of bottom thickness, 0.3 mm or more is preferable from the viewpoint of the breakdown strength, and 0.6 mm or less is preferable from the viewpoint of miniaturization and weight reduction of the heat exchanger.

In addition, the height H of the inner protruding pin is 0.1 to 0.4 mm, the vertex angle α of the inner protruding pin is 10 to 40 °, and the number of the inner protruding pin is 40 or more, and the lead angle β (the inner protruding pin and the Angle of the tube in the longitudinal direction) is preferably 20 ° or more.

After carrying out a rolling process, you may perform an annealing softening process. This is to remove the dents in the processing introduced at the time of rolling and to facilitate the hairpin bending processing (meandering bending processing). What is necessary is just to perform an annealing at 300-400 degreeC for 2 to 8 hours by a regular method.

The pipe having the inner groove of the present embodiment thus manufactured is brought into close contact with the insertion hole of the aluminum heat dissipation fin by expanding tube processing. In order to achieve good adhesion, it is appropriate to set the clearance between the insertion hole and the heat transfer pipe so that the expansion rate (outer diameter increase rate) is about 4 to 6%. On the other hand, expansion of a pipe | tube process can improve production efficiency by the hydraulic pipe | tube expansion method which gives the internal pressure (??) to a pipe by hydraulic or hydraulic pressure instead of the mechanical expansion method using a mandrel.

Second Embodiment: Heat Exchanger

Another embodiment of the present invention is a heat exchanger provided with a heat transfer tube according to the above embodiment. Since the heat exchanger is provided with a heat exchanger tube which is hard to generate fin crushing, it is excellent in heat transfer performance and excellent in efficiency. Alternatively, the heat exchanger is excellent in heat transfer performance and durability because the heat exchanger is provided with a heat transfer tube which is hard to generate fin crush and excellent in corrosion resistance.

Embodiment 3: air conditioner

Another embodiment of the present invention is an air conditioner including the heat transfer tube according to the above embodiment. Since the air conditioner is provided with a heat transfer tube which is hard to generate pin crush, it is excellent in heat transfer performance and excellent in efficiency. The air conditioner is excellent in heat transfer performance and durability because the air conditioner is provided with a heat transfer tube that is hard to generate pin crush and has excellent corrosion resistance.

Although the embodiments of the present invention have been described above, they are examples of the present invention, and various configurations other than the above may be employed.

<Examples>

Next, the present invention will be described in more detail with reference to Examples.

The cylindrical billet of the aluminum alloy of the component composition shown in Table 1 was cast, and the extruded pipe of outer diameter (phi) 47 mm and thickness was 3.5 mm by the indirect extrusion method. Drawing processing was performed to the said extruded tube by the draw block type continuous drawing machine, and the drawing tube of outer diameter (phi) 10 mm and thickness was 0.45 mm was obtained.

For Nos. 8 to 14 and Nos. 22 to 28, where the sacrificial anticorrosive layer was formed, the cylindrical billet of the sacrificial anticorrosive material of A1050 or A7072 was heated to 450 ° C., and the cylindrical core billet of the sacrificial corrosion material was inserted thereinto. A layer hollow billet was obtained, this was indirectly extruded, and then the drawing process was carried out by a draw block type continuous drawing machine, and a drawing tube having an outer diameter φ 10 mm and a thickness of 0.48 mm was similarly obtained.

After performing the loosening softening treatment at 360 ° C. for 2 hours on the thus-obtained drawing tube, a plug having a floating plug, a rod, and a grooved plug was inserted, and the inner surface was passed through a floating die, a processing head, and a forming die. The inner surface is machined to have a groove in the outer diameter: φ7mm, bottom thickness: 0.35mm, height of projecting pin H: 0.22mm, number of projecting pins 50, vertex angle α: 15 °, lead angle β: 35 ° A tube with a groove was made. On the other hand, about No8-14 and No21-26, it adjusted to the billet thickness of the sacrificial anticorrosive material in an extrusion process so that the said sacrificial anticorrosive layer might be 0.035 mm (ratio of 10% with respect to bottom thickness). Furthermore, the annealing softening process was performed for 2 hours at 360 degreeC finally, and the tube which has an inner groove was completed.

In order to evaluate the characteristic of the pipe | tube which has the inner groove of this invention example and comparative example obtained in this way, the following test was done. The obtained results are shown in Table 2.

(a) Tensile test

In order to measure the strength of the tube having an inner groove, a tensile test based on JIS Z2241 was performed.

(b) Expandability

The pipe having the inner groove having the outer diameter φ 7 mm was expanded by using a forced mandrel such that the outer diameter was increased by 5%. Then, the cross section of the pipe was observed, and the amount of pin crushing was evaluated by measuring the decrease amount of the height H of the protruding pin. In order to obtain heat transfer characteristics as a heat exchanger, the fin crushing amount is preferably 0.01 mm or less. Moreover, the hardness of the center part of the protrusion pin cross section before and behind expansion pipe processing was measured with the micro Vickers hardness tester.

(c) corrosion resistance

In order to evaluate external corrosion resistance, the CASS test was performed for 1500 hours with respect to the pipe which has each inner groove based on JISZ8681. After the test, the surface corrosion products of the test tubes were removed, the corrosion state of the tubes was observed, and the external corrosion resistance was evaluated by the presence or absence of through holes.

As shown in Table 2, the pipes No1 to No14 having inner grooves made of aluminum of the present invention had a decrease in the height H of the protruding pins (pin distortion) of 0.01 mm or less, and the hardness of the protruding pin portions before expansion. The amount of pin distortion of No3 to No7 and No10 to No14 described above is 0, which is very good. Moreover, No8-No14 which provided the sacrificial anticorrosive layer does not show generation | occurrence | production of a through hole, and external corrosion resistance is favorable. Further, the tensile strength of the tube is 119 MPa or more, for example, the strength is higher than that of 91 MPa (corresponding to A3003) of Comparative Example No16, and thus the pressure resistance of the tube is also high, so that the material cost due to thinning can be reduced.

On the other hand, No15-No18 and No22-No25 with small amount of Mn and Mg have large distortion of the protruding pin at the time of expansion, and the intensity | strength of the pipe itself is also low. On the contrary, No19-No21 and No26-No28 having a large amount of Mn and Mg are broken in the drawing process or the rolling process, and a pipe having an inner groove could not be manufactured.

The present invention has been described above based on the embodiments. The above embodiments are only examples, and there may be various modified examples, and it should be understood by those skilled in the art that such modified examples fall within the scope of the present invention.

1: aluminum heat dissipation fin
2: Heat pipe (tube with inner groove)
3: louver
4: expansion plug (mandrel)
5: smooth pipe
6: rolling plug
7: rotary roll
8: tube with inner spiral groove
9: protrusion pin
10: victim anticorrosion floor

Claims (8)

A plurality of protruding fins are formed on the inner surface, Mn: 0.8-1.8 mass% (hereinafter referred to as% by mass), Mg: 0.1-0.6%, and the balance is made of Al and unavoidable impurities. Heat pipe having an inner groove made of an aluminum alloy. A plurality of protruding fins are formed on the inner surface, Mn: 0.8-1.8%, Mg: 0.1-0.6%, Fe: 0.60% or less, Si: 0.60% or less, Cu: 0.30% or less, Zn: 0.30 Inner surface made of aluminum alloy, containing one or two or more of% or less, Cr: 0.20% or less, Ti: 0.20% or less, Zr: 0.20% or less, and the balance consists of Al and unavoidable impurities Heat pipe with groove. The method according to claim 1 or 2,
Heat transfer tube having an inner groove made of an aluminum alloy, characterized in that the hardness of the protruding fin is HV33 or more. The method according to any one of claims 1 to 3,
A heat transfer tube having an inner groove made of an aluminum alloy, characterized in that a pure Al or Al-Zn alloy layer is formed on the outer surface as a sacrificial anticorrosive material. The method according to any one of claims 1 to 4,
Heat pipe having an inner groove made of an aluminum alloy, the outer diameter of the heat pipe, 4.0mm ~ 9.54mm. The method according to any one of claims 1 to 5,
Heat transfer tube having an inner groove made of an aluminum alloy, the bottom thickness of the heat transfer tube, 0.3mm ~ 0.6mm. The heat exchanger provided with the heat exchanger tube of any one of Claims 1-6. The air conditioner provided with the heat exchanger tube in any one of Claims 1-6.

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