JP2009264711A - Member for heat exchanger and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To form a thin and uniform zinc welding part having a high area coverage ratio, in the manufacturing members for a heat exchanger. <P>SOLUTION: The heat exchanger member has the zinc welding part, formed by welding particles comprising zinc or alloy containing zinc on the surface of a base material comprising aluminum or aluminum alloy. In the zinc welding part, the area coverage ratio of a portion where the base material is covered with the welding particles exceeds 30%, the average particle size of the welding particles is 150 μm or smaller, and the standard deviation of the particle size is 70 μm or smaller. The zinc welding part is formed, by performing electric arc spraying onto a wire with 0.8-1.3 mm of wire diameter on the surface of the base material. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a heat exchanger component manufactured by brazing, and relates to a heat exchanger member having a surface on which a zinc adhesion portion is formed, and a method for manufacturing the same.

  In order to improve the corrosion resistance of the aluminum heat exchanger, a technique for forming a sacrificial corrosion layer (zinc adhesion portion) by spraying zinc or a zinc-containing alloy on the surface of the tube to deposit zinc is already known ( Patent Document 1).

  With such a zinc spray tube, stable spraying is difficult with a low deposition amount, and zinc cannot be deposited uniformly and thinly. Further, even if a low adhesion amount is achieved, the tube surface is not uniformly adhered, and there are problems with the perforated corrosion resistance of the tube because the adhering part and the non-adhering part coexist. Further, when the amount of zinc adhesion was increased in order to eliminate the non-adhered portion, the zinc was concentrated in the fillet at the fin / tube junction, and the phenomenon that the fillet was preferentially corroded occurred, and the fin peeling occurred.

For this reason, as a method of depositing zinc thinly and uniformly, the A1-Zn alloy is sprayed to reduce the substantial amount of zinc deposited, or by using a zinc substitution flux, zinc is deposited thinly and evenly to prevent fin peeling. A method for preventing this has been proposed (see Patent Document 2).
Japanese Patent Laid-Open No. 04-15496 JP 2003-225760 A

  However, in the method using a flux exhibiting a zinc substitution reaction, it is necessary to decompose the resin component by heating at the time of brazing and the coating process for applying the resin as a binder, and a large equipment change is necessary in the heating process. there were.

  For this reason, there is a need for a technique for forming a thin and uniform zinc adhering portion with few unattached portions by thermal spraying at a relatively low equipment cost.

  In view of the technical background described above, the present invention provides a heat exchanger member having a thin and uniform zinc adhering portion with a high coverage area ratio, a method for producing a heat exchanger member that forms such a zinc adhering portion by thermal spraying, and It aims at providing the manufacturing method of the heat exchanger using the member for heat exchangers.

  That is, the heat exchanger member of the present invention has a configuration described in [1] to [5] below.

[1] A heat exchanger member having a zinc adhesion part formed by welding particles made of zinc or a zinc-containing alloy on the surface of a base material made of aluminum or an aluminum alloy,
In the zinc adhesion part, the covering area ratio of the portion where the base material is coated with the welding particles is 30% or more, the average particle size of the welding particles is 150 μm or less, and the standard deviation of the particle size is 70 μm or less. The member for heat exchangers characterized by the above-mentioned.

[2] The heat exchanger member as recited in the aforementioned Item 1, wherein the zinc adhesion amount in the zinc adhesion part is 0.3 to 10 g / m ² .

  [3] The heat exchanger member according to item 1 or 2, wherein the covering area ratio is 50% or more.

  [4] The heat exchanger member according to any one of items 1 to 3, wherein an average particle size of the welding particles is 140 μm or less.

  [5] The heat exchanger member according to any one of items 1 to 4, wherein a standard deviation of the particle size of the weld particles is 60 μm or less.

  Moreover, the manufacturing method of the member for heat exchangers of this invention has the structure as described in following [6]-[8].

  [6] A wire made of zinc or a zinc-containing alloy and having a wire diameter of 0.8 to 1.3 mm is arc sprayed on the surface of a base material made of aluminum or an aluminum alloy, and melted metal particles are adhered to the surface of the zinc adhering portion. The manufacturing method of the member for heat exchangers characterized by forming.

  [7] The method for producing a member for a heat exchanger as recited in the aforementioned Item 6, wherein the wire has a wire diameter of 0.8 to 1.1 mm.

  [8] The method for producing a heat exchanger member as recited in the aforementioned Item 6 or 7, wherein the substrate is an extruded material.

  Furthermore, the manufacturing method of the heat exchanger of this invention has the structure as described in following [9].

[9] Tubes and fins are alternately stacked to form a core, and the heat exchanger is temporarily assembled by connecting the tube of the core to the header tank in a communicating state, and the temporarily assembled heat exchanger is heated. In the heat exchanger manufacturing method for brazing the tube and the header tank, and the tube and the fin,
The heat exchanger member according to any one of claims 1 to 5 is used as at least one of the tube, the header tank, and the fin, and the zinc in the zinc adhering portion is diffused into the base material by heating during brazing and sacrificed. A method for producing a heat exchanger, wherein a corrosive layer is formed.

  The invention described in [1] has a zinc adhering portion formed by welding particles made of zinc or a zinc-containing alloy on the surface of a base material. In this zinc adhesion part, since the covering area ratio of the part where the base material is coated with the welding particles is high and the welding particles are miniaturized, the zinc adhesion part is thin and uniform. For this reason, the zinc of the zinc adhering portion diffuses by heating to form a uniform sacrificial corrosion layer, and excellent corrosion resistance can be obtained.

  Each invention described in the above [2] to [5] has a particularly thin and uniform zinc adhering portion.

  In the invention described in [6] above, since a wire having a wire diameter of 0.8 to 1.3 mm is used as a thermal spraying material for arc spraying, particles deposited on the surface of the base material are fine and thin. A uniform zinc adhesion part can be formed and a high coverage area ratio can be obtained. For this reason, a uniform heat sacrificial corrosion layer can be formed by the zinc diffusion of the zinc adhesion part by heating, and the member for heat exchangers which has excellent corrosion resistance can be manufactured.

  According to the invention described in [7] above, a particularly thin and uniform zinc adhesion portion can be formed.

  According to the invention described in [8] above, a member for a heat exchanger can be efficiently manufactured.

  The invention described in [9] above uses the heat exchanger member according to any one of [1] to [5] as at least one of a tube, a header tank, and a fin. Zinc diffuses by heating to form a sacrificial corrosion layer, and a heat exchanger having excellent corrosion resistance can be manufactured.

  The member for a heat exchanger of the present invention has a zinc adhesion part formed by welding particles made of zinc or a zinc-containing alloy on the surface of a base material made of aluminum or an aluminum alloy. In such a heat exchanger member, zinc adhered by heating, for example, heating at the time of brazing diffuses into the surface layer portion of the base material, and a sacrificial corrosion layer is formed.

  In the present invention, the type of the heat exchanger member is not limited. For example, in the heat exchanger (1) shown in FIG. 1, the tubes (2) and the fins (3) are alternately stacked, and the ends of the tubes (2) are connected to the header tank (4). The core portion is formed by brazing the tube (2) and the fin (3) and the tube (2) and the header tank (4). The heat exchanger member of the present invention can be applied to any of the tube (2), the fin (3), and the header tank (4). In the heat exchanger (1) of FIG. 1, the side plate (5) is brazed to the outermost fin (3). The production method of the present invention can be applied before the heat exchanger member is brazed, and can be applied to each heat exchanger member before brazing, as well as for heat exchangers such as fins, tubes, and header tanks. You may apply this invention to materials, such as a board | plate material and a pipe material, before manufacturing a member.

  FIG. 2 shows a flat multi-hole heat exchanger tube (2) as an example of the heat exchanger member of the present invention. The heat exchanger tube (2) has zinc adhering portions (2b) on two opposing flat walls of the substrate (2a).

  The zinc adhering portion (2b) is formed by thermal spraying, which will be described later, and is composed of welding particles (20) made of innumerable zinc or a zinc-containing alloy as shown in FIG. In the zinc adhering portion (2b), the surface of the base material (2a) does not need to be covered with the welding particles (20), and the non-adhering portion not covered with the welding particles (20) as in the illustrated example ( 21) is also present. In the present invention, since the weld particles (20) are fine, a thin and uniform zinc adhering portion (2b) is obtained, and a higher coating area ratio is obtained. Specifically, the covering area ratio of the portion where the base material (2a) is coated with the welding particles (20) is 30% or more, the average particle size of the welding particles is 150 μm or less, and the standard deviation of the particle size is 70 μm. Must be:

  When the covering area ratio is less than 30%, there are too many unattached portions (21), and the corrosion resistance is deteriorated. A particularly preferable covering area ratio is 50% or more. The present invention does not define the upper limit value of the covering area ratio, and the present invention also applies when the base material (2a) is completely covered with the weld particles (20) at the covering area ratio of 100% and there is no unattached portion (21). However, even if the covering area ratio is less than 100%, sufficient corrosion resistance required for the heat exchanger can be obtained.

  In addition, the weld particles (20) having a smaller particle size and less variation form a thinner and uniform zinc adhesion portion, thereby achieving a high coverage area ratio. If the average particle size exceeds 150 μm or the standard deviation exceeds 70 μm and the variation becomes large, it becomes difficult to form a thin and uniform zinc adhering portion (2b). A preferable average particle diameter of the weld particles is 140 μm or less, and a preferable standard deviation of the particle diameter is 60 μm or less.

  The weld particles (20) are not necessarily perfect circles. When the weld particle (20) is not a perfect circle, the particle diameter is the equivalent circle diameter of the same area, and the average particle diameter and the standard deviation are calculated based on the equivalent circle diameter. Further, when the weld particles (20) are overlapped, the contour shape of the weld particles (20) is measured based on the unevenness of each particle of the overlapped portion, and the equivalent circle diameter of the same area is calculated from the contour shape. calculate.

The welding particles (20), that is, the wire for thermal spraying to be described later, may be zinc alone or a zinc-containing alloy. The zinc adhesion amount per unit surface area in the zinc adhesion part (2b) is preferably 0.3 to 10 g / m ² as a substantial amount of zinc. If it is less than 0.3 g / m ² , the sacrificial corrosion effect becomes small, and there is a concern that the pitting corrosion resistance is lowered. On the other hand, if it exceeds 10 g / m ² , it will be difficult to obtain long-term corrosion resistance. Moreover, since excellent corrosion resistance is obtained at 10 g / m ² or less, it is economically disadvantageous to deposit an amount of zinc exceeding that. A particularly preferable zinc adhesion amount is 0.5 to 8 g / m ² .

  The material of the base material (2a) of the heat exchanger member is not limited as long as it is aluminum or an alloy thereof, and known materials can be used as appropriate. As the tube material, a JIS 1000 series aluminum alloy, an aluminum alloy added with a trace amount of Cu and Mn, and a JIS 3000 series aluminum alloy can be recommended. As the fin material, an aluminum alloy obtained by adding Zn to JIS 3203 can be recommended, and as the header tank material, JIS 3003 alloy can be recommended.

  The structure of the thermal spray gun that performs thermal spraying is not limited at all. For example, an arc is generated between two wires that are thermal spray materials (zinc or zinc-containing alloy) to melt the wire, and compressed air is supplied from the rear to make the molten metal into particles and blown forward. Thus, what is welded to the surface of the substrate (2a) can be listed.

  In the manufacture of the heat exchanger member described above, the refinement of the weld particles (20) can be achieved by using a wire having a thin wire diameter to be supplied to the spray gun. In the present invention, the wire diameter is 0. • Use 8-1.3 mm wire. If the wire diameter exceeds 1.3 mm, the particle size of the weld particles increases and the coverage area ratio decreases. On the other hand, since a wire having a thin wire diameter is expensive, it is economically disadvantageous to use a thin wire having a wire diameter of less than 0.8 mm. A particularly preferable wire diameter is 0.8 to 1.1 mm.

  FIG. 4 shows an apparatus configuration example for manufacturing the heat exchanger tube (2). In this figure, spray guns (11) and (11) are arranged above and below the exit side of the extruder (10), and are sequentially pushed out of the extruder (10) to move the two flat walls of the moving base material (2a). It is configured to spray continuously. In this way, by continuously forming and spraying the base material (2a) by extrusion, the formation of the zinc adhering portion (2b) can be performed efficiently, and thus the heat exchanger member (2) can be efficiently manufactured. Can do.

  In addition, the manufacturing method of the member for heat exchangers of this invention is not limited to performing a base material, shaping | molding, and thermal spraying continuously, It can also implement by the process independent of manufacture and thermal spraying of a base material. For example, a base material manufactured in a separate process can be wound around a coil and sprayed while unwinding the base material of the coil. Since the heat exchanger member manufactured by these methods is a long material, it is used by appropriately cutting to a required length. Further, the thermal spraying can be performed not only on a long base material but also after the base material is cut into a predetermined length.

  As described above, according to the present invention, in the formation of the zinc adhering portion by thermal spraying on the surface of the base material, the weld particles can be made fine and the zinc can be adhered uniformly and thinly. Since the formed zinc adhesion portion is a thin and uniform layer, the zinc diffuses into the surface layer portion of the base material by heating to form a uniform sacrificial corrosion layer, and excellent corrosion resistance is obtained. Moreover, since the excellent corrosion resistance is obtained with a small amount of zinc adhesion, the consumption of zinc can be reduced.

<Production of heat exchanger tubes>
The base material (2a) of the heat exchanger tube (2) uses a JIS 1000 series aluminum alloy (Cu: 0.4% by mass, Mn: 0.2% by mass, with the balance consisting of Al and inevitable impurities). A multi-hole flat tube (2a) having a width of 16 mm, a height of 3 mm, and a thickness of 0.5 mm shown in FIG. As shown in Fig. 4, the heat exchanger tube (2) is manufactured by placing an arc spray gun (11) loaded with zinc wire with the wire diameter shown in Table 1 above and below the outlet of the extruder (10). Then, the multi-hole flat tube (2a) is extruded from the extruder (10), and is successively sprayed onto the two flat walls of the multi-hole flat tube (2a) which is being pushed out and moved, and the zinc adhering portion (2b ). The manufactured heat exchanger tube (2) was wound around a coil, and then cut into a required length while unwinding the coil.

  The following items were evaluated for the manufactured heat exchanger tubes.

<Zinc adhesion part>
In the zinc adhering portion (2b), the particle size of the weld particles (20) having a diameter of 30 μm or more was measured, and the average particle size and the standard deviation were obtained. In addition, the area ratio is determined by measuring the area ratio of the area where the weld particles (20) cover the base material (2a) in a 10 mm × 10 mm area, and calculating the average value of the five measured areas. Rate. The reason why the weld particles having a diameter of less than 30 μm are excluded is that they are too fine, so that there is almost no influence on the amount of adhesion and no influence on the corrosion resistance. These results are also shown in Table 1.

<Corrosion resistance>
Each of the manufactured heat exchanger tubes (2), brazing fins (3), and header tank (4) was temporarily assembled and brazed to prepare a front heat exchanger (1) shown in FIG. The brazing heat was 600 ° C. × 10 min. By this heating, zinc was diffused in the surface layer portion of the heat exchanger tube (2) to form a sacrificial corrosion layer.

  For each brazed heat exchanger, the SWAAT test specified in ASTM-G85-A3 was performed. As the corrosion test solution, an artificial seawater according to ASTM D1141 was prepared, and a corrosion test solution prepared by adding acetic acid to the artificial seawater to a pH of 3 was used. Further, the test conditions were 0.5 hour spray-wet 1.5 hour as one cycle, and this cycle was carried out for 480 hours. Furthermore, for those that obtained good results in the 480 hour corrosion test, a further 480 hours were extended and a total 960 hour corrosion test was performed.

  Corrosion resistance was evaluated according to the following criteria after the corrosion test. Table 1 also shows the evaluation results.

○: No fillet preferential corrosion and good in the 960 hour corrosion test Δ: Maximum corrosion depth is equivalent to ○ and good in the 480 hour corrosion test ×: Corrosion depth is 200 μm Any of the above or pitting corrosion

  From the results shown in Table 1, in each example, by using a wire having a thin wire diameter, the weld particles can be miniaturized and the variation in the particle diameter can be reduced, and the coating area ratio is high with a small amount of zinc adhesion. A uniform zinc deposit could be formed. And the corrosion resistance excellent in the long term was able to be obtained by this zinc adhesion part. On the other hand, in the comparative example using a wire with a large wire diameter, the particle size of the weld particles was large, and even with the same amount of zinc adhesion as in the example, the coating area ratio was small, so the corrosion resistance was poor.

  According to the present invention, zinc can be deposited thinly and uniformly on the surface of the base material of the heat exchanger member. For this reason, it can utilize for manufacture of the various heat exchangers which require long-term corrosion resistance.

It is a front view which shows an example of a heat exchanger. It is sectional drawing which shows an example of the member for heat exchangers. FIG. 3 is a partially enlarged view of FIG. 2. It is a schematic diagram which shows the manufacturing process of the member for heat exchangers.

Explanation of symbols

1… Heat exchanger
2 ... Tube (heat exchanger component)
2a… Base material
2b… Zinc adhesion part
10 ... Extruder
11 ... Thermal spray gun
20 ... welded particles
21… Unattached part

Claims (9)

A heat exchanger member having a zinc adhesion part formed by welding particles made of zinc or a zinc-containing alloy on the surface of a base material made of aluminum or an aluminum alloy,
In the zinc adhesion part, the covering area ratio of the portion where the base material is coated with the welding particles is 30% or more, the average particle size of the welding particles is 150 μm or less, and the standard deviation of the particle size is 70 μm or less. The member for heat exchangers characterized by the above-mentioned. The member for heat exchangers of Claim 1 whose zinc adhesion amount in the said zinc adhesion part is 0.3-10 g / m < ² >.   The heat exchanger member according to claim 1 or 2, wherein the covering area ratio is 50% or more.   The member for a heat exchanger according to any one of claims 1 to 3, wherein an average particle size of the welding particles is 140 µm or less.   The heat exchanger member according to any one of claims 1 to 4, wherein a standard deviation of the particle size of the weld particles is 60 µm or less.   A wire made of zinc or a zinc-containing alloy and having a wire diameter of 0.8 to 1.3 mm is arc sprayed on the surface of a base material made of aluminum or an aluminum alloy, and molten metal particles are adhered to form a zinc adhesion portion. The manufacturing method of the member for heat exchangers characterized by the above-mentioned.   The manufacturing method of the member for heat exchangers of Claim 6 whose wire diameter of the said wire is 0.8-1.1 mm.   The said base material is an extrusion material, The manufacturing method of the member for heat exchangers of Claim 6 or 7. Tubing and fins are alternately stacked to form a core part, and the heat exchanger is temporarily assembled by connecting the tube of the core part to the header tank in a communicating state, and the temporarily assembled heat exchanger is heated to In a method of manufacturing a heat exchanger for brazing a tube and a header tank and a tube and a fin,
The heat exchanger member according to any one of claims 1 to 5 is used as at least one of the tube, the header tank, and the fin, and the zinc in the zinc adhering portion is diffused into the base material by heating during brazing and sacrificed. A method for producing a heat exchanger, wherein a corrosive layer is formed.

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