JP5350017B2 - Plate for tube manufacturing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve excellent brazing even when heat exchange medium passages are narrow and replacement with brazing atmosphere is difficult, in manufacturing a flat multihole type tube for a heat exchanger made by bending a plate-shaped body. <P>SOLUTION: In the plate-shaped body (10) for brazing, partition wall forming parts (15) are swollen along the longitudinal direction on one face of a flat plate part (11), and the plate-shaped body (10) for brazing is bent to form the tube. The partition wall forming parts (15) are brazed to form the plurality of partitioned heat exchange medium passages, so as to manufacture the flat multihole type aluminum tube. The plate-shaped body (11) has brazing filler metal (10b) on one face of a core material (10a), and Mg concentration in aluminum constituting the core material (10a) is 0.01 mass% or less. The brazing filler metal (10b) comprises aluminum allow including 5-12 mass% of Si concentration, 0.003-0.03 mass% of Sr concentration, 0.005 mass% or less of Mg concentration, 0.002 mass% or less of Ca concentration and remaining comprising Al and unavoidable impurities. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a plate-like body that is a material for producing a flat multi-hole type heat exchanger tube, and a related technique.

  In the present specification and claims, the term “aluminum” is used to include both pure aluminum and aluminum alloys.

  As a method for manufacturing a flat multi-hole type heat exchanger tube, a plurality of partition wall forming portions are raised on one side of an aluminum plate by rolling with grooved rolls, die forming, roll forming, etc. This tube manufacturing plate-like body is bent into a hairpin shape and the edges are brazed to form a tube, and the partition wall forming portion that is abutted is brazed to form a plurality of heat exchange media in the tube. A method of partitioning into a passage is known. According to this manufacturing method, the tube can be thinned, and the heat exchanger can be reduced in size and weight (see Patent Documents 1 and 2).

JP-A-6-281373 JP 2006-78163 A

  In the manufacture of a flat multi-hole heat exchanger tube, brazing is performed in a non-oxidizing raw atmosphere such as nitrogen gas in order to achieve good brazing. However, since the heat exchange medium passage becomes narrower as the tube becomes thinner and thinner, it becomes difficult to replace the air in the passage with the brazing atmosphere. For this reason, the brazing material starts to melt while oxygen remains in the passage, and the oxide produced by oxidizing the constituent elements of the brazing material delays brazing, and it takes time to braze. was there.

  In view of the technical background described above, the present invention is good even when a flat multi-hole type heat exchanger tube manufactured by bending a plate-like body is manufactured and the heat exchange medium passage is narrow and difficult to replace with a brazing atmosphere. It aims at providing the plate-shaped object for tube manufacture which can be brazed, and its related technique.

  That is, the present invention has the configurations described in [1] to [9] below.

[1] A partition wall forming portion is raised along the longitudinal direction on one surface of the flat plate portion, and is bent to braze end portions in the width direction to form a tube and to braze the partition wall forming portion. By attaching, it is a plate member for brazing for producing a flat multi-hole aluminum tube in which the inside of the tube is partitioned into a plurality of heat exchange medium passages,
The plate-like body has a brazing material on the surface where the partition wall forming portion of the core material is raised,
Mg concentration in aluminum constituting the core material is 0.01% by mass or less,
The brazing filler metal is Si concentration: 5-12% by mass, Sr concentration: 0.003-0.03% by mass, Mg concentration: 0.005% by mass or less, Ca concentration: 0.002% by mass or less, and the balance Is made of an aluminum alloy composed of Al and inevitable impurities.

  [2] The plate-like body for manufacturing a tube according to item 1 above, wherein an average particle diameter of Si in the brazing material is 3.5 μm or less.

  [3] The plate-like body for producing a tube according to the above item 1 or 2, wherein the equivalent circle diameter of at least one heat exchange medium passage is 0.8 mm or less.

  [4] The plate-like body for manufacturing a tube according to any one of items 1 to 3, wherein the core material and the brazing material are clad.

[5] A method for producing a plate-like body for producing a tube according to item 4,
A tube manufacturing plate characterized in that a core material and a brazing material manufactured without homogenization are overlapped to produce a clad material, and a partition wall forming portion is raised on the brazing material side surface of the clad material A method of manufacturing a body.

  [6] The tube-forming plate according to any one of the preceding items 1 to 4 is bent with the brazing material side inward, the ends in the width direction are brought into contact with each other, and the tube is formed. A method for producing a heat exchanger tube, characterized in that a partition wall forming portion partitions the inside of the tube into a plurality of heat exchange medium passages to form a flat multi-hole heat exchanger tube and performs brazing addition heat.

  [7] The method for producing a heat exchanger tube as recited in the aforementioned Item 6, wherein the brazing heat is performed in an atmosphere having an oxygen concentration of 300 ppm or less.

  [8] The method for producing a heat exchanger tube as described in 6 or 7 above, wherein the rate of temperature rise at the start of brazing addition heat is 50 ° C./min or more.

[9] The tubes and fins are alternately stacked, and the core portion is temporarily assembled in a state where the header tank is connected to the tubes, and the temporarily assembled core portions are heated to form the tubes, fins, and tubes. In the method of manufacturing a heat exchanger for brazing the header tank,
As the tube, using a flat multi-hole type tube formed by bending the plate-like body for tube production according to any one of the preceding items 1 to 4,
A method of manufacturing a heat exchanger, comprising: melting a brazing material of a tube-made working plate-like body by the heating to braze the inside of a heat exchanger tube.

  According to the tube manufacturing plate-like body described in [1] above, since the Mg concentration in the core material, the Mg concentration in the brazing material, and the Ca concentration are regulated, the amounts of oxides of these elements generated during brazing Is suppressed. Further, since the Si particles are refined by Sr in the brazing material, the brazing material is melted in a short time, and the growth of the Al oxide film is suppressed, and a decrease in the fluidity of the brazing material can be suppressed. The oxides of Mg and Ca and the oxide film of Al both delay brazing and make brazing in a short time difficult. Brazing is achieved in a short time. Furthermore, by suppressing these generations, the allowable range of the oxygen concentration in the brazing atmosphere for achieving good brazing is relaxed, so that the inside of the passage is brazed because the heat exchange medium passage is small. Even in a tube that is difficult to be replaced by the atmosphere, good brazing can be achieved.

  In the tube-working plate according to the above [2], since the average particle diameter of Si in the brazing material is refined to 3.5 μm or less, the brazing material melts particularly quickly and is good. Brazing can be achieved.

  According to the tube manufacturing plate-like body described in [3] above, good brazing can be achieved even for a tube having a narrow heat exchange medium passage having an equivalent circle diameter of 0.8 mm or less.

  According to the tube-working plate-like body described in [4] above, good brazability can be achieved in a plate-like body manufactured from a core material and a clad material of brazing material.

  According to the method for producing a tube-working plate-like body described in [5] above, a tube-working plate-like body in which Si particles in the brazing material are miniaturized is produced using a clad material of a core material and a brazing material. can do.

  According to the method for manufacturing a heat exchanger tube as described in [6] above, the formation of Ca and Mg oxides that lower the brazing property is suppressed, and the growth of the Al oxide film is suppressed. The attached tube can be manufactured.

  According to the method for manufacturing a heat exchanger tube described in [7] and [8] above, generation of Ca and Mg oxides and growth of an Al oxide film are particularly suppressed.

  According to the heat exchanger manufacturing method of [9] above, brazing of the heat exchanger tube, brazing of the heat exchanger tube and the header, and brazing of the heat exchanger tube and the outer fin are simultaneously performed. Can do.

It is sectional drawing which shows an example of the tube for heat exchangers manufactured from the plate-shaped object for tube manufacture of this invention. It is sectional drawing which shows the process of bending the plate-shaped object for tube manufacture in the manufacturing method of the tube for heat exchangers of this invention. It is a figure which shows the manufacturing method of the plate-shaped object for tube manufacture of FIG. It is a front view of the heat exchanger using the tube for heat exchangers of FIG.

  FIG. 1 shows an example of a heat exchanger tube (1) produced from the tube production plate of the present invention. This heat exchanger tube (1) is formed into a tube shape by the opposed upper and lower flat walls (2) (3) and left and right side walls (4) (5), and the inside of the tube is divided into a plurality of heat by the partition wall (6). It is a flat multi-hole tube partitioned by an exchange medium passage (7). For convenience of explanation, the up and down direction and the left and right direction in the drawing are the up and down and left and right directions of the tube, but these directions do not limit the arrangement direction of the tube.

  As shown in FIG. 2, the heat exchanger tube (1) is manufactured by bending a belt-shaped tube manufacturing plate (10) and brazing the contact portion.

  The tube manufacturing plate-like body (10) is a substantially plate-like body having a plurality of types of raised portions along the longitudinal direction on one surface of the belt-like flat plate portion (11). A right side wall forming portion (14) serving as a right side wall (4) protrudes from a central portion of the flat plate portion (11), and left and right portions of the right side wall forming portion (14) are lower flat wall forming portions (12). And the upper flat wall forming portion (13), and the flat wall forming portions (12) and (13) are provided with partition wall forming portions (15) protruding at predetermined intervals. In addition, a first left side wall forming part (17) protrudes from an end of the lower flat wall forming part (12), and a second left side is formed in a portion retracted inward from the end of the upper flat wall forming part (13). A wall forming part (18) is projected. An end portion of the upper flat wall forming portion (13) is a side wall covering portion (19). That is, the tube manufacturing plate-like body (10) has a right side wall (14), a first left side wall forming part (17), and a second left side wall forming part (18) on one surface of the flat plate part (11). ), A plurality of partition wall forming portions (15) project, and the region where the partition wall forming portion (15) projects is substantially the upper and lower flat wall forming portions (12) (13). In the following description, when a plurality of types of portions protruding from the flat plate portion (11) are shown, they are referred to as “bumped portions”.

  As shown in the partially enlarged view in FIG. 2, the plate-like body for tube production (10) has a brazing material (10b) on one surface side of the core material (10a) and an outer skin material (10c) on the other surface side. It is manufactured by applying a process of raising the raised portions (14), (15), (17), and (18) on the brazing material (10b) side of this material.

  The raised portions (14), (15), (17), and (18) are raised by using a rolling machine in which a plurality of sets of upper and lower sets of rolling rolls are arranged in series, and rolling the material while raising the raised portions (14) (15 ) (17) A method for forming (18) can be exemplified.

  FIG. 3 schematically shows a state during forming by a pair of rolling rolls (30) and (31) in a rolling apparatus, and the horizontal direction of the drawing shows the width direction of the material (32). The clearance gap between each set of rolling rolls (30) and (31) is set to be narrower than the thickness of the material (32) from the insertion side to the exit side of the material (32). Each set of rolling rolls has a flat peripheral surface and a flat lower roll (30) that forms the outer surface side of the tube, whereas the upper roll (31) that forms the inner surface side of the tube has a raised portion. (14) (15) (17) (18) A plurality of kinds of annular grooves (33) (34) for forming are formed (only two annular grooves are shown). The shape of the annular groove (33) (34) varies depending on the raised portions (14) (15) (17) (18) to be formed. The plurality of upper rolls (31) arranged have a plurality of types of annular grooves corresponding to the ridges (14), (15), (17), and (18), and any of the annular grooves protrudes from the material (32) insertion side. Designed so that the groove width gradually becomes narrower and deeper toward the side, the groove shape of the last roll is the raised part (14) (15) (17) (18) shape of the plate for tube manufacturing (10) Corresponding to

  Then, by passing the material (32) through the rolling device having the above configuration, the thickness of the material (32) is gradually reduced by the rolling action, and the metal of the reduced thickness gradually becomes the annular groove (33) (34). The raised portions (14), (15), (17), and (18) are formed.

  According to the rolling by the grooved roll described above, a plurality of raised portions having different shapes can be raised simultaneously. In addition, the manufacturing method of the plate-shaped object for tube manufacture used for this invention is not limited to the rolling by a grooved roll. As other methods, uplift molding using a mold or uplift molding using a roll can be exemplified.

  The tube-made working plate (10) is formed into a flat multi-hole tube by bending, and the heat contact tube (1) is joined by brazing and joining the abutted portions by bending. Become.

  Molding of the tube manufacturing plate-like body (10) into the flat multi-hole type heat exchanger tube (1) is carried out in the following steps, as shown in FIGS.

  The tube-made working plate-like body (10) bends the lower flat wall forming portion (12) and the upper flat wall forming portion (13) around the right side wall forming portion (14), and finally bends into a hairpin shape. The right side wall forming part (14) becomes the right side wall (4) as it is. Further, when the first left side wall forming part (17) and the second left side wall forming part (18) are abutted, and the side wall covering part (19) is further bent and caulked, they are brought into close contact with each other and the left side wall (5) To form a tube with upper and lower flat walls (2) (3) and left and right side walls (4) (5). At the same time, the partition wall forming part (15) of the lower flat wall forming part (12) and the partition wall forming part (15) of the upper flat wall forming part (13) are brought into contact with each other to form a partition wall (6). Is partitioned into a plurality of heat exchange medium passages (7).

  The heat exchanger tube (1) formed into a flat multi-hole mold is heated to melt the brazing material (10b) and braze-join each contact portion. In the present invention, as described in detail below, since the core material (10a) and the brazing material (10b) are regulated to have a composition that suppresses the formation of a brazing retarding substance, the heat exchange medium passage (7) Even if the gas is narrow and the replacement with the non-oxidizing brazing atmosphere in the passage (7) is delayed, it is possible to achieve good brazing inside the tube.

  As the core material (10a), aluminum having an Mg concentration of 0.01% by mass or less is used. When the Mg concentration of the core material (10a) exceeds 0.01% by mass, it becomes easy to form an oxide by reacting with oxygen in a temperature rising process at the time of brazing, that is, in a state where the substitution to the brazing atmosphere is not sufficient, The generated oxide takes time to braze. Also, when a clad material having a skin material on the other surface side of the core material (10a) is used, Mg diffuses to the surface of the skin material and forms an oxide, which causes brazing delay. For this reason, it is necessary to regulate the Mg concentration to 0.01% by mass or less, and the preferable Mg concentration is 0.007% by mass or less. Moreover, although a lower limit is not prescribed | regulated, since the cost of the lump used as a mother alloy increases, 0.002 mass% or more is preferable.

  The balance composition of the core material (10a) is Al and inevitable impurities.

  The brazing filler metal has an Si concentration of 5 to 12 mass%, an Sr concentration of 0.003 to 0.03 mass, an Mg concentration of 0.005 mass% or less, a Ca concentration of 0.002 mass% or less, and the balance being Al. And an aluminum alloy composed of inevitable impurities.

  The Si concentration is 5 to 12% by mass in order to ensure the melting point of the desired brazing material, and the preferred range is 7 to 12% by mass.

  Sr is an element added to refine the Si particles and melt the brazing material in a short time during the temperature rise. By melting the brazing material near the eutectic temperature in a short time, a decrease in the fluidity of the brazing material due to the growth of the Al oxide film is suppressed, thereby achieving good brazing in a short time. If the Sr concentration is less than 0.003% by mass, the effect is poor, and if it exceeds 0.03% by mass, it is uneconomical. A preferable Sr concentration is 0.007 to 0.02 mass%.

  In Mg and Ca, these oxides are causative substances of brazing delay, so in order to suppress these oxides in the heat of brazing addition, the Mg concentration is 0.005% by mass or less and the Ca concentration is 0.002%. It is necessary to regulate to less than mass%. Further, the Mg concentration is preferably 0.004% by mass or less, and the Ca concentration is preferably 0.0015% by mass or less. Moreover, although a lower limit is not prescribed | regulated, since the cost of the lump used as a mother alloy goes up, the lower limit of Mg concentration is preferable 0.002 mass%, and the lower limit of Ca concentration is preferable 0.001 mass%.

  The “mother alloy” used in the description of the composition of the core material and the brazing material described above is an aluminum ingot as a material and a mother alloy when the alloy components are added in the mother alloy (adjusted to the desired composition) Alloy) and both.

  The average particle diameter of the Si particles in the brazing material is preferably refined to 3.5 μm or less. Since the brazing material is melted near the eutectic temperature due to the refinement of the Si particles, the brazing material is melted quickly and in a short time. For this reason, the fluidity | liquidity fall of the brazing material by the growth of the oxide film of Al is suppressed, and brazing property improves. When the average particle diameter of Si exceeds 3.5 μm, the effect of accelerating the melting timing is poor. A particularly preferable average particle diameter of Si is 3.0 μm or less. In the present invention, the Si particle diameter is measured by a cross section, and is expressed as a circle equivalent diameter of a particle cross section (a diameter of a circle having the same area as the particle cross sectional area). The average particle diameter is the average of the numbers (the sum of the particle diameters of n particles present in the observation field divided by n).

  The skin material (10c) is a layer for brazing the tube, the outer fin, and the header and imparting corrosion resistance to the tube by sacrificial corrosion, and is made of, for example, an aluminum alloy to which Si and Zn are added. Examples of the aluminum alloy include an Al—Si alloy, an Al—Zn alloy, and an Al—Si—Zn alloy, and the Si concentration in these alloys is preferably 5 to 12% by mass, and the Zn concentration is 0.5 to 4 Mass% is preferred.

  As described above, the plate manufacturing body (10) of the present embodiment is obtained by rolling the plate-shaped core material (10a), the brazing material (10b), and the outer skin material (10c) to a required thickness. Manufactured using clad material. The Si particle diameter in the brazing material can also be controlled in the brazing material manufacturing process, the cladding material manufacturing process, and the bulge forming process. That is, it is only necessary to prevent heat treatment at a high temperature in order to prevent Si particles from growing either in the single material before cladding or in the cladding material with the core material. Specifically, the growth of Si particles can be suppressed by not performing the homogenization treatment on the brazing material before cladding. Further, when hot rolling is performed at the time of producing a brazing material alone or at the time of producing a clad material, the growth of Si particles can be suppressed by rolling at a low temperature. Specifically, it is preferable to perform hot rolling at 500 ° C. or less.

  Furthermore, the brazing property can be improved by selecting conditions that can suppress the formation of Mg and Ca oxides and the growth of the Al oxide film during brazing heat.

  Needless to say, the lower the oxygen concentration in the brazing atmosphere is, the more the formation of oxides and oxide films is suppressed. However, the present invention defines the brazing material composition and the core material composition, and further oxidizes by miniaturizing the Si particles. Therefore, the allowable range of the oxygen concentration in the brazing atmosphere is relaxed. Specifically, good brazing can be achieved if the oxygen concentration in the brazing atmosphere is 300 ppm or less. A particularly preferable oxygen concentration is 100 ppm or less. Therefore, good brazing can be achieved even in a state where the heat exchange medium passage (7) is narrow, the substitution with a brazing atmosphere gas such as nitrogen gas is incomplete, and oxygen remains.

  Also, when the temperature is rapidly increased at the start of the brazing addition heat, the formation of Mg and Ca oxides and the growth of the Al oxide film are suppressed, and the brazing property is improved. Specifically, it is preferable to increase the temperature at 50 ° C./min or more, and it is particularly preferable to increase the temperature at 70 ° C./min or more.

  In the present invention, the dimensions of the heat exchanger tube are not limited at all. However, since the formation of oxide during brazing addition heat is suppressed, the air in the passage is brazed because the cross-sectional area of the heat exchange medium passage is small. Significantly applicable to tubes that are difficult to replace. It is suitable for manufacturing a tube having an equivalent circle diameter in the cross section of the heat exchange medium passage, that is, a circle equivalent diameter in a cross section perpendicular to the longitudinal direction of the passage of 0.8 mm or less, particularly for a tube having an equivalent circle diameter of 0.7 mm or less. Is preferred. The circle equivalent diameter is a diameter of a circle having the same area as the cross-sectional area of the passage. Moreover, although the heat exchanger tube of the present invention is a multi-hole type, if the equivalent circle diameter of at least one of the plurality of heat exchange medium passages is 0.8 mm or less, the application significance of the present invention is great. .

  In the above embodiment, the tube-made working plate and the heat exchanger tube made of the core material, the brazing material as the inner skin material, and the three-layer clad material of the outer skin material are exemplified, but the present invention is made of the three-layer clad material. It is not limited to that. The tube material according to the present invention only needs to have a brazing material on one side of the core material (the surface on the side where the raised portion is formed), and a two-layer clad material in which the brazing material is combined with the core material as an endothelium material is also included in the present invention. include. The presence or absence of the outer skin material is arbitrary, and even when the outer skin material is provided, the configuration (alloy composition, number of layers, thickness) is arbitrary, and the outer skin material is not limited to being a brazing material or a sacrificial corrosion material. Furthermore, what was manufactured with the clad material which has an intermediate material between a core material and a brazing material (endothelium material) is also contained in this invention. Furthermore, the present invention also relates to a tube working plate-like body manufactured by forming a raised portion on a flat plate as a core material and then attaching a brazing material to a portion to be brazed by coating or high-speed spraying method. include. Among the above-mentioned brazing material adhesion methods, the former is a method in which a powdery brazing material is mixed with a binder to form a liquid or a paste, and this brazing material mixture is applied to a portion to be brazed. The latter high-speed spraying method is a method in which a powder brazing material is sprayed at a high speed and particles are caused to collide with a portion to be brazed and adhered without using a binder. In any method, the flux can be attached simultaneously with the brazing material.

  In the present invention, the shape of the raised portion of the tube-made working plate is not limited to that illustrated. For example, the tube-shaped plate-like body (10) in the example shown in the figure increases the thickness of the side walls (4) and (5) by raising the side wall forming portions (14), (17) and (18) to increase the tube strength. However, the side wall can be formed only by bending the flat plate without raising the side wall forming portion. Further, the partition wall (6) may be brought into contact with the other flat wall forming portion by increasing the height of the partition wall forming portion (15). Furthermore, it is also optional to project an inner fin in the heat exchange medium passage (7).

  The heat addition heat of the heat exchanger tube may be performed by the tube alone, or may be performed in a state where the formed heat exchanger tube is temporarily assembled together with other members such as a header as shown in FIG.

  In the heat exchanger (20) shown in FIG. 4, a plurality of heat exchanger tubes (1) are laminated with outer fins (21) interposed therebetween, and both ends of the heat exchanger tube (1) are stacked. Is connected to the header (22) and has a core portion in which the heat exchanger tube (1), the outer fin (21), and the header (22) are joined and integrated by brazing. In the figure, (23) is a side plate.

  The heat exchanger tubes (1) formed by bending and outer fins (21) made of brazing sheets are alternately stacked, and the heat exchanger tubes (1) are flattened on the header (22) made of brazing sheets at both ends. Insert it into the hole and temporarily assemble it. A flux is applied to the temporary assembly and heated. As a result of this heating, the heat exchanger tube (1) melts the brazing filler metal and the flux adhered to the tube working plate (10), and the first left side wall forming part (17) and the second left side wall forming part (18 ), The butted partition wall moldings (15) and (15) are brazed to each other. The heat exchanger tube (1) and the header (22) are brazed and joined by the brazing material layer of the header (22), and the heat exchanger tube (1) and the outer fin ( 21) is brazed.

  A three-layer clad material in which a core material having a Mg concentration shown in Table 1 is clad with a brazing material having the composition shown in Table 1 as an endothelial material and an outer brazing material made of an Al-8 mass% Si-2 mass% Zn alloy as an outer skin material. Produced. The three-layer clad material has a clad rate of 7% for the endothelial material and 8% for the clad material. Table 1 shows whether or not the brazing material is homogenized in the production of the clad material.

  Using the clad material as a material (32), rolling is performed using the upper roll (31) having the annular grooves (33) and (34) for forming the raised portions shown in FIG. 3 and the flat lower roll (30). A tube working plate-like body (10) shown in Fig. 2 was produced. The tube working plate (10) is rolled so that the thickness of the thinnest part is 250 μm, and the equivalent circle diameter of the heat exchange medium passage (7) after the tube forming is 0.7 mm. Raised parts (14) (15) (17) (18) were formed.

KAlF ₄ flux is adhered to the surface of the manufactured tube plate (10) on the brazing material (10b) side, and each tube plate (10) is attached as shown in FIGS. It was bent into a flat multi-hole type heat exchanger tube (1). Then, as shown in FIG. 4, these heat exchanger tubes (1), together with a separately manufactured outer fin (21) and header (22), the core of the heat exchanger (20) shown in FIG. The parts were temporarily assembled and flux was applied, and the temperature was raised to 600 ° C. at a rate shown in Table 1 and brazed at 600 ° C. for 5 minutes in a nitrogen gas atmosphere containing oxygen at the concentrations shown in Table 1. .

  After brazing, the inner surface of the tube was observed with an SEM to examine the amounts of Mg and Ca oxides, and evaluated according to the following criteria based on the result of applying an internal pressure of 8 MPa into the core.

  (Double-circle): A partition wall and a side wall are brazed favorable and there are few amounts of the oxide of Mg and Ca. In addition, the tube does not swell or break even when internal pressure is applied.

  ○: The partition wall and the side wall are brazed well, and the tube does not swell or break even when an internal pressure is applied, but the amount of oxides of Mg and Ca is larger than “◎”.

  Δ: The amount of Mg and Ca oxide is larger than “◯”, but the tube does not swell or break even when an internal pressure is applied, and there is no problem in brazing.

  X: The amount of oxides of Mg and Ca is larger than “Δ”, the partition walls and the side walls are not brazed well, and the tube is swollen or broken when an internal pressure is applied.

  Table 1 shows an outline of the manufacturing conditions of the heat exchanger tube and the evaluation results.

  From Table 1, it was confirmed that favorable brazing could be achieved even in a heat exchanger tube having a heat exchange medium passage having a small cross-sectional area, by the alloy composition of the core material and the brazing material.

  INDUSTRIAL APPLICABILITY The present invention can be used for manufacturing a miniaturized flat multi-hole heat exchanger tube.

1… Tube for heat exchanger
2 ... Bottom flat wall
3… Upper flat wall
4 ... right side wall
5 ... Left wall
6 ... Partition wall
7… Heat exchange medium passage
10 ... Plate for tube manufacturing
11: Flat plate
12, 13 ... Flat wall forming part
14 ... Right side wall forming part (side wall forming part)
15 ... Partition wall forming part
17 ... 1st left side wall formation part (side wall formation part)
18 ... 2nd left side wall formation part (side wall formation part)
19 ... Side wall cover
20 ... Heat exchanger
21 ... Outer fin
22 ... Header

Claims (9)

A partition wall forming portion is raised along the longitudinal direction on one surface of the flat plate portion, bent to braze the end portions in the width direction to form a tube and braze the partition wall forming portion. Is a brazing plate for producing a flat multi-hole aluminum tube in which the inside of the tube is partitioned into a plurality of heat exchange medium passages,
The plate-like body has a brazing material on the surface where the partition wall forming portion of the core material is raised,
Mg concentration in aluminum constituting the core material is 0.01% by mass or less,
The brazing filler metal is Si concentration: 5-12% by mass, Sr concentration: 0.003-0.03% by mass, Mg concentration: 0.005% by mass or less, Ca concentration: 0.002% by mass or less, and the balance Is made of an aluminum alloy composed of Al and inevitable impurities.   The plate-like body for producing a tube according to claim 1, wherein an average particle diameter of Si in the brazing material is 3.5 µm or less.   The plate-like body for producing a tube according to claim 1 or 2, wherein the at least one heat exchange medium passage has a circle-equivalent diameter of 0.8 mm or less.   The plate-like body for manufacturing a tube according to any one of claims 1 to 3, wherein the core material and the brazing material are clad. A method for producing a plate-like body for producing a tube according to claim 4,
A tube manufacturing plate characterized in that a core material and a brazing material manufactured without homogenization are overlapped to produce a clad material, and a partition wall forming portion is raised on the brazing material side surface of the clad material A method of manufacturing a body.   The tube-shaped plate for manufacturing a tube according to any one of claims 1 to 4, wherein the tube is formed by bending the brazing material side inward to bring the end portions in the width direction into contact with each other, and the partition wall A method for producing a heat exchanger tube, characterized by forming a flat multi-hole type heat exchanger tube by partitioning the inside of the tube into a plurality of heat exchange medium passages by a forming portion, and performing brazing addition heat.   The manufacturing method of the tube for heat exchangers of Claim 6 which performs brazing addition heat in the atmosphere whose oxygen concentration is 300 ppm or less.   The manufacturing method of the tube for heat exchangers of Claim 6 or 7 which makes the temperature increase rate at the time of a brazing addition heat start 50 degreeC / min or more. The tubes and fins are alternately stacked and the core portion is temporarily assembled in a state where the header tank is connected to the tubes, and the temporarily assembled core portions are heated to connect the tubes and fins, and the tubes and header tanks. In the manufacturing method of the heat exchanger to be brazed,
As the tube, using a flat multi-hole tube formed by bending a plate-like body for producing a tube according to any one of claims 1 to 4,
A method of manufacturing a heat exchanger, comprising: melting a brazing material of a tube-made working plate-like body by the heating to braze the inside of a heat exchanger tube.

Images