JP5713451B2 - Aluminum alloy brazing sheet and manufacturing method thereof, and brazing method of aluminum heat exchanger - Google Patents

Description

  The present invention relates to an aluminum alloy brazing sheet, and more specifically, an aluminum alloy brazing sheet that can be brazed without applying a flux during brazing heating, a method for producing the same, and the aluminum alloy brazing sheet. The present invention relates to a brazing method for an aluminum heat exchanger.

  Currently, most automotive heat exchangers apply a fluoride flux to a brazing sheet made by cladding an Al-Mn core material with an Al-Si brazing material, and heat it in an inert gas atmosphere furnace such as nitrogen gas. It is brazed and joined. However, with the recent digitization of automobile parts, some heat exchangers have been pointed out with problems such as flux residue after brazing hindering surface treatment, and for higher performance. However, in the heat exchanger having a fine refrigerant passage, there is also a problem that the flux residue closes the refrigerant passage and the heat exchange performance is greatly reduced.

  In order to solve such a problem, a technique for brazing without applying flux is required. Conventionally, as a technique for brazing without applying flux, there is a vacuum brazing method in which an Al—Si—Mg brazing material is used and brazing is performed by heating in a vacuum furnace. Can be completely joined without flux, but brazing equipment costs are expensive, Mg cleaning and maintenance of pumps and instruments are expensive, and it is inactive because it relies on radiant heating There is a drawback that productivity is also inferior to brazing in a gas furnace.

For precision brazed parts with narrow electronic parts and refrigerant passages, in addition to completely joining without flux, it is possible to reduce the amount of flux used to a level where there is no problem. In a general brazing environment, when the amount of flux applied is less than 3 g / m ² , the brazing property is drastically lowered. This is thought to be due to the fact that the flux function deteriorates because the amount of oxygen contained in the atmosphere reacts with the flux and oxidizes during brazing heating, in addition to reducing the amount of flux. Yes. In addition, the deterioration of the flux function due to such oxidative deterioration becomes more remarkable particularly in a flux containing CsF that melts from a low temperature or a Cs-based flux, and a low melting point flux containing Cs is used for brazing in a furnace. There is a problem that it is difficult.

  In order not to cause deterioration due to oxidation of the flux during brazing heating, it has been attempted to enclose the flux in a brazing sheet. As a technique, a flux encapsulating member made of an aluminum alloy material encapsulating the flux is used as a brazing material and a core material. (Patent Document 1), a space portion defined by an aluminum alloy spacer is filled with powdered flux, and the whole is hot-rolled to form an aluminum alloy plate and A method (Patent Document 2) has been proposed in which a spacer is hot-pressed and, at the same time, the powder powder inside is pressed and solidified.

  However, in any of the methods, the flux becomes a barrier and hot rolling properties are hindered, and during hot rolling, the flux is scattered around the equipment and contaminates the equipment. This is industrially difficult to realize. Also, a method of manufacturing a brazing sheet for aluminum brazing by placing a flux-containing wire formed by wrapping a flux in an aluminum foil between layers of a core material and a brazing material and rolling the laminate (Patent Document 3) is also available. Although it has been proposed, the problems of ensuring hot rollability and flux scattering have not been solved.

JP 2001-259886 A JP 2002-361487 A JP 2007-260781 A

  The present invention was made as a result of various tests and examinations in order to eliminate the above-mentioned conventional problems in the method of enclosing flux in a brazing sheet, and its purpose is to inhibit hot rolling properties. Aluminum alloy brazing sheet and method for producing the same, and aluminum incorporating the brazing sheet, which can avoid the problem that the flux is scattered during hot rolling to contaminate the equipment or be mixed into other rolling materials. The object is to provide a method for brazing a heat exchanger.

  In order to achieve the above object, an aluminum alloy brazing sheet according to claim 1 is a brazing sheet used for a heat exchanger that is brazed and joined by heating without applying a flux in an inert gas atmosphere. Then, one or both surfaces of the core material are clad with an Al—Si based aluminum alloy brazing material (hereinafter referred to as a brazing material) containing Si: 6 to 13% (mass%, the same applies hereinafter), and the interface between the core material and the brazing material. Includes a mixture of a fluoride-based flux and a metal powder having a solidus temperature of 565 ° C. or lower, and a part or all of the mixture is solidified after melting. .

The aluminum alloy brazing sheet according to claim 2 is the aluminum alloy brazing sheet according to claim 1, wherein the Mg content of the brazing material and the core material is limited to 0.05% or less, and the amount of flux in the mixture contained in the interface is 2 0.0 g / m ² or less.

  The aluminum alloy brazing sheet according to claim 3 is the aluminum alloy brazing sheet according to claim 1 or 2, wherein the brazing material is further one or two of Zn: 0.5 to 10% and Cu: 0.2 to 3.0%. It is characterized by containing.

  An aluminum alloy brazing sheet according to claim 4 is a brazing sheet used for a heat exchanger that is brazed and joined by heating without applying a flux in an inert gas atmosphere, on one or both sides of a core material. , Si: Al-Si brazing material containing 6 to 13% is clad into two layers. At the interface between the brazing material and the brazing material clad into two layers, fluoride flux and solidus temperature are A mixture with metal powder of 565 ° C. or lower is included, and a part or all of the mixture is solidified after being melted.

  The aluminum alloy brazing sheet according to claim 5 is the metal powder having a flux of fluoride and a solidus temperature of 565 ° C. or less at the interface between the brazing material and the brazing material and the interface between the core material and the brazing material. And the mixture is solidified after melting part or all of the mixture.

The aluminum alloy brazing sheet according to claim 6 is the aluminum alloy brazing sheet according to claim 4 or 5, wherein the Mg content of the brazing material clad in the two layers is limited to 0.05% or less, and the Mg content of the core material is 0.00. It is limited to not more than 05%, and the amount of flux in the mixture included in the interface is 2.0 g / m ² or less.

  An aluminum alloy brazing sheet according to a seventh aspect of the present invention is the aluminum alloy brazing sheet according to any one of the fourth to sixth aspects, further comprising: Zn: 0.5 to 10%, Cu: 0. It contains 1 type or 2 types in 2-3.0%, It is characterized by the above-mentioned.

  An aluminum alloy brazing sheet according to claim 8 is a brazing sheet used in a heat exchanger that is brazed and joined by heating without applying a flux in an inert gas atmosphere, and is formed on one side of a core material with Si Clad Al: Si brazing material containing Si: 6-13% through an intermediate material of aluminum alloy containing less than 6%, and clad aluminum alloy skin on the other side of the core material, The interface between the aluminum alloy brazing material and the intermediate material contains a mixture of a fluoride-based flux and a metal powder having a solidus temperature of 565 ° C. or less, and a part or all of the mixture is solidified after being melted. It is characterized by that.

The aluminum alloy brazing sheet according to claim 9 is the aluminum alloy brazing sheet according to claim 8, wherein the Mg content of the brazing material, the intermediate material, the core material and the skin material is limited to 0.05% or less, and is included in the interface between the brazing material and the intermediate material. The amount of flux in the mixture is 2.0 g / m ² or less.

  The aluminum alloy brazing sheet according to claim 10 is any one of claims 8 to 9, further comprising Zn: 0.5 to 10%, Cu: 0.2 to It is characterized by containing one or two of 3.0%.

  A method for producing an aluminum alloy brazing sheet according to claim 11 is a method for producing an aluminum alloy brazing sheet according to any one of claims 1 to 10, wherein a core material and a brazing material are laminated as a clad constituent material, or A core material, an intermediate material, a brazing material and a skin material are laminated, and a mixture of fluoride-based flux and metal powder is included in the interface, and hot clad rolling (hereinafter, simply hot Prior to (rolling), the laminated clad components are heated and bonded while being pressed.

  A manufacturing method of an aluminum alloy brazing sheet according to claim 12 is the method according to claim 11, wherein the core material and the brazing material as the clad constituent material, or the core material, the intermediate material, the brazing material and the skin material are laminated at the interface. A mixture of a fluoride-based flux and a metal powder having a solidus temperature of 565 ° C. or lower is disposed at the interface, and the clad constituent material laminated with the mixture sandwiched is pressurized and heated. Thus, a part or all of the mixture is melted and joined, and then hot-rolled.

  According to a thirteenth aspect of the present invention, there is provided a method for producing an aluminum alloy brazing sheet according to the eleventh or twelfth aspect, wherein a mixture outflow prevention member is provided so as to surround a periphery of an interface for sandwiching the mixture.

A brazing method for an aluminum heat exchanger according to claim 14 is the aluminum alloy brazing sheet according to any one of claims 1 to 10, wherein a flux amount in the mixture included in the interface is 1.0 g / m. by assembling those with ² or less, without applying flux in an inert gas atmosphere, and performing heating to within 4 minutes heating-up period to 590 ° C. from 450 ° C..

  According to the present invention, it is possible to avoid a problem that the flux is scattered during hot rolling and contaminates the apparatus or is mixed into other rolling materials without impairing hot rolling properties. An aluminum alloy brazing sheet enclosing (including) a flux and a method for producing the same are provided, and further, a brazing method for an aluminum heat exchanger incorporating the brazing sheet is provided.

FIG. 5 is a schematic perspective view showing an example of a mixture outflow prevention member provided so as to surround the periphery of the interface when the mixture is sandwiched at the interface in order to enclose the mixture at the interface of the core material and the brazing material. It is a partial cross section figure showing other examples of a mixture outflow prevention member. It is a figure which shows the gap filling test piece used in an Example.

  The basic structure of the aluminum alloy brazing sheet of the present invention is that one side or both sides of a core material is clad with an Al—Si brazing material containing Si: 6 to 13%, and at the interface between the core material and the brazing material, A mixture of a fluoride flux and a metal powder having a solidus temperature of 565 ° C. or lower is included, and a part or all of the mixture is solidified after being melted (Claim 1). .

  One or both surfaces of the core material are clad with two layers of an Al—Si brazing material containing Si: 6 to 13%, and are clad into the interface between the brazing material and the brazing material clad into two layers or into two layers. The mixture may be included in the interface between the brazing material and the brazing material and the interface between the core material and the brazing material, and a part or all of the mixture may be melted and then solidified. Item 5).

  Also, an Al—Si brazing material containing Si: 6 to 13% is clad on one side of the core material through an aluminum alloy intermediate material containing Si: less than 6%, and the other side of the core material is made of aluminum alloy. The mixture is encapsulated in the interface between the aluminum alloy brazing material and the intermediate material, and a part or the whole of the mixture is melted and solidified after being melted. Claim 8).

  When the brazing material is clad on one side of the core material, nothing is clad on the other side of the core material, and depending on the application, a skin material such as a sacrificial anode material can also be clad. When clad with two layers of brazing material, the same is true when brazing the brazing material via an intermediate material.

Examples of the core material of the aluminum alloy brazing sheet according to the present invention include pure aluminum such as JIS-A1050 and A1100, and A3003, A3203, and A3004 in which Cu, Si, Fe, Cr, Zn, Ti, Zr, etc. are added to an Al-Mn alloy. Known aluminum alloys for heat exchangers such as Al-Mn aluminum alloys can be used. However, since Mg in the core material reacts with the flux to form an MgF ₂ compound and reduce the function as the flux, it is preferably limited to 0.05% or less.

  As the brazing material, a conventional Al—Si based aluminum alloy can be used. That is, an Al—Si alloy or an Al—Si alloy containing a small amount of additive components can be used. However, the Si content needs to be 6 to 13%. If the Si content is less than 6%, the fluidity of the wax is lowered, and sufficient bonding cannot be performed. If it exceeds 13%, coarse Si grains are formed, and the melted wax melts the core material and other members, which is not preferable.

  When the brazing material is clad into two layers, the brazing material of each layer may contain 6 to 13% of Si, and the Si content of the brazing material of each layer may be the same or different. The intermediate material containing Si: less than 6% may be an aluminum alloy containing less than 6% Si and the balance aluminum and unavoidable impurities, and an aluminum alloy added with Mn, Zn, and other alloy components. It can also be used. The intermediate material may have the same component as the core material.

  When the brazing material contains one or two of Zn: 0.5 to 10% and Cu: 0.2 to 3.0%, the melting point of the brazing material decreases, so heating before hot rolling It becomes easy to join the brazing material and the core material.

  The most characteristic feature of the present invention is that a mixture of a fluoride-based flux encapsulated in the brazing sheet of the present invention and a metal powder having a solidus temperature of 565 ° C. or lower is solidified after part or all of the mixture is melted. Is to do. As a method of encapsulating the solidified part or all of the mixture after melting, it is solidified after part or all of the mixture is melted directly at the interface between the core material and the brazing material, the brazing material and the brazing material, etc. Things may be arranged by an appropriate method and hot rolled to form a brazing sheet, but in actual production, in the process prior to hot rolling, the mixture is applied in powder form to the interface and once melted, It is preferable to hot-roll after cooling and solidifying after making it into a liquid state, and scattering of the mixture containing the flux in a rolling process can be prevented.

  By including the mixture containing the flux in the brazing sheet, the flux application step in the production of the heat exchanger becomes unnecessary. In addition, the flux is not exposed to the atmosphere until the solder is melted, so that oxidation deterioration of the flux during brazing heating can be prevented and the amount of flux used can be reduced.

  In the present invention, the clad constituent material laminated in the process prior to hot rolling by mixing the flux with a low melting point metal powder having a solidus temperature of 565 ° C. or lower, rather than enclosing only the flux. Since the constituent materials can be metallically bonded to each other at the interface, it is possible to improve the clad bonding property and to surely enclose the flux at the interface of the constituent materials.

  In order to melt part or all of the flux and the low melting point metal powder, a homogenization treatment step or a heat treatment step before hot rolling can be used. That is, a clad constituent material is laminated, a flux and a metal powder having a low melting point are arranged at the interface thereof, and homogenized, or the clad constituent material laminated before hot rolling is heated. As a result, the laminated materials are bonded to each other between metals, and rolling defects such as peeling during hot rolling are less likely to occur, and the clad rate and material strength are not limited, which is difficult in the past. It becomes possible to manufacture a material having a low cladding rate or a high cladding rate. Furthermore, the accuracy of the cladding rate can be stabilized.

  In the present invention, a clad structure laminated with a molten metal is applied to the interface of a clad constituent material for laminating a mixture of a flux and a metal powder having a low melting point, and heated to melt part or all of it. Since the materials are partially bonded to each other, the flux is confined at the interface of the clad constituent materials to be laminated. In addition, since part or all of the flux melts, even if part of it flows out to the side of the laminated clad constituent material, it solidifies and adheres closely to the clad constituent material. Will not scatter. Further, in the process of processing the brazing sheet into the shape of the heat exchanger member, even if the brazing material is torn, the flux is not scattered.

Fluoride flux (nocolok flux) containing KF and AlF ₃ as basic components, flux obtained by mixing CsF with the fluoride flux, Cs-Al-F flux, Cs-K-Al-F flux, etc. Is non-corrosive to aluminum and does not react with aluminum. In the present invention, since the flux is melted and solidified, each component of the brazing sheet is basically encapsulated between the core material and the brazing material. Then, there is no oxidative deterioration. Therefore, the temperature of the heat exchanger exceeds the melting point of the flux by brazing heating, the flux is remelted, and the function as the flux can be sufficiently achieved. Since the remelted flux has a lighter specific gravity than aluminum, when the brazing material starts to melt, it floats on the surface of the brazing material, destroys the oxide film, and contributes to peeling. Thereafter, when cooled, the amount of surplus flux remaining on the material surface becomes smaller than in the case of normal flux application. Therefore, even if the refrigerant passage is very small, it is difficult for the flux residue to block the refrigerant passage.

By remelting the flux without oxidative degradation, the amount of flux used can be reduced as compared with the case where the flux is applied to the surface of the material. In normal flux brazing, in the case of a Nocolok flux having KF-AlF ₃ as a basic component, it is necessary to apply 3 g / m ² or more on the outer surface side of the heat exchanger where the flux is oxidized and deteriorated during heating. In the present invention, since the flux is confined between the clad components without oxidative deterioration, the function can be achieved even at ² g / m ² or less. Moreover, in brazing heating, by heating from 450 ° C. to 590 ° C. within 4 minutes, good brazing properties can be obtained even if the amount of flux contained at the interface between the brazing materials is 1 g / m ² or less. It was confirmed.

The flux amount X (g / m ² ) contained in the brazing sheet is the flux amount A (g / m ² ) applied to the interface of the laminated cladding component and the total thickness t0 (mm) of the laminated cladding component. Further, from the thickness t (mm) of the rolled brazing sheet, it can be obtained by a calculation formula of X = A · (t / t0).

  In the present invention, as a means for encapsulating a mixture of flux and low melting point metal powder in the brazing sheet, the mixture is applied to the interface of the clad component laminated before hot rolling, and heated to a predetermined temperature to melt. It is desirable to apply a method in which the clad constituent materials are bonded to each other entirely or partially. The part in which the mixture is encapsulated is basically the interface between the brazing material and the core material, but it is more preferred to encapsulate in the part close to the surface of the brazing sheet, so that the brazing material is clad in two layers (Claim 4). ) Is included in the interface between the first layer brazing material and the second layer brazing material, and when the brazing material is clad through the intermediate material (Claim 8), it is included in the interface between the brazing material and the intermediate material. Since the flux is present at a position close to the surface, the effect of the flux can be further enhanced.

  When brazing a brazing material to two layers, when brazing the brazing material at the interface between the brazing material of the first layer (surface layer) and the second layer and via an intermediate material, the intermediate material and the brazing material It is preferable to encapsulate the mixture of flux and metal powder at the interface, but the mixture may or may not be applied to the interface between the brazing material and the core material of the second layer and the interface between the intermediate material and the core material. Even in this case, the object of the present invention can be achieved.

  In the present invention, before hot rolling, a clad constituent material in which a mixture of a flux and a metal powder having a low melting point is disposed or applied at a predetermined interface is clad-joined by hot rolling, and hot rolling and cold rolling. Therefore, the amount of flux applied per unit area is several hundred to 1,000 times or more the amount of flux that functions during brazing. As a means for uniformly arranging a large amount of flux, in the present invention, a method is used in which a metal powder having a solidus temperature lower than that of the Al—Si brazing material and a flux are mixed and arranged or applied.

The metal powder serves to prevent the uneven distribution of the flux and to disperse it evenly, and also functions as a bonding material in the bonding of the clad constituent material before hot rolling. The characteristics required for the metal powder are that the solidus temperature is lower than the Al—Si brazing material (solidus temperature 577 ° C.), function as a bonding material, and do not hinder the action of the flux. It is desirable that mass production is possible in terms of cost. As the metal powder, Zn powder having a low melting point, Al—Zn alloy powder, Al—Cu alloy, or Al—Zn—Cu alloy powder can be used. Si may be added to these alloys. In addition, a metal powder that causes eutectic melting with Al and has a eutectic temperature of 565 ° C. or lower, such as pure Cu powder, can also be applied. The amount of the metal powder applied or disposed is preferably 3 to 10 g / m ² .

When bonding the clad constituting material of the brazing sheet, it is effective to press the entire surface while heating the laminated clad constituting material in order to ensure the bonding. The entire surface can be pressurized by placing a plate-shaped jig with a heat-resistant spring on the surface of the laminated clad component, pressurizing it, fixing it with bolts, and aluminum made on the laminated clad component. There are a method of putting a heavy material such as a slab and a steel plate and pressurizing the clad constituting material by its own weight, and a method of heating while pressing in a press machine. The applied pressure is preferably 10 × 10 ⁻³ MPa or less. When the applied pressure exceeds 10 × 10 ⁻³ MPa, the melted flux tends to leak from the side surface of the laminated clad constituent material.

  In order to prevent the melted flux from leaking from the interface of the laminated clad constituent material to the side surface, as shown in FIG. 1, the surface on which the mixture 1 of the flux and metal powder is applied or arranged (in this case, the surface of the core material) It is preferable to install the mixture outflow prevention member 2 around. The thickness t and height h of the mixture outflow prevention member 2 are adjusted according to the amount of the mixture to be applied or arranged.

  As the mixture outflow prevention member 2, as shown in FIG. 2, an aluminum frame 4 made of an aluminum extruded shape provided with a wide portion 3 can also be used. In FIG. 2, the position when the mixture 1 of the flux and metal powder is arranged is indicated by a broken line X, and the position at the time of melting is indicated by a broken line Y. By disposing the mixture outflow prevention member 2, the melted flux and the metal powder can be strongly pressurized without flowing out around the laminated clad constituent material.

  Excess gas is discharged from the melted flux and metal powder by the strong pressurization at the time of joining, so that the blistering that occurs after hot rolling is prevented in advance and the flux is uniform if the metal powder is in a semi-molten state. Dispersibility is reliably maintained. Although the mixture outflow prevention member 2 is hot-rolled together with the laminated clad constituent material, the mixture outflow prevention member 2 is located only at the end portions in the width direction and the longitudinal direction of the clad constituent material, so that it is cut off during the rolling process. There is no loss of material quality or yield.

  Moreover, in order to hold | maintain a flux more reliably at the interface of the clad structure material laminated | stacked, a recessed part can also be shape | molded on the surface of the material of the side which applies a flux. A shape such as a triangle, a quadrangle, or a semicircle is suitable as the shape of the recess, but the shape is not limited to this. Moreover, even if it is a continuous linear recessed part, the recessed part independent in the dimple shape may be sufficient. It is preferable to form the recesses in a regular pattern such as a linear shape, a concentric circle shape, a spiral shape, or a lattice shape because the distribution of the contained flux becomes uniform. As a method for forming the concave portion, it is preferable to form the concave portion by a method such as cutting, press molding, or rolling down with a roll on which the convex portion is formed.

  As an effective means for further facilitating the joining of the laminated clad components, Zn and Cu can be added to the brazing material to lower the melting point of the brazing material, and further, Si and Cu can be used for the intermediate material and the core material. More reliable bonding can be performed by adding Zn or the like to lower the melting point of the intermediate material or the core material.

  Since the mixture of the flux and the metal powder is shielded from the atmosphere by the laminated clad constituent materials, the heating for joining the clad constituent materials before hot rolling to enclose the mixture in the brazing sheet is performed in the atmosphere. Since the flux is not oxidized and deteriorated even in the air, it can be carried out in the atmosphere. Of course, it may be performed in an inert gas atmosphere. The heating temperature is preferably 500 to 575 ° C. If the temperature exceeds 577 ° C., the brazing material will melt, making it impossible to produce a brazing sheet. Moreover, if it is less than 500 degreeC, a metal powder will not fully fuse | melt or a flux will not fully activate, and joining of each structural material of the interface which apply | coated the mixture of a flux and a metal powder will become inadequate.

  By the joining of the clad constituent material before hot rolling, the flux is included in the interface of the joining portion without being deteriorated by oxidation, and is remelted during brazing heating and functions again as the flux. Because there is almost no deterioration due to oxidation, the required amount of flux is reduced compared to normal coating, and no surplus residue remains on the surface of the brazing material. The surface becomes clean enough to have no adverse effects.

  The cost required to encapsulate the mixture containing the flux before hot rolling is smaller than the cost of applying the flux before brazing after assembling the heat exchanger, and the joining of the clad components before hot rolling is Since it can be carried out using the homogenization treatment or heating before hot rolling, which is generally performed, the increase in cost can be suppressed, and the total cost of brazed products can be reduced. This is an excellent advantage of the invention.

  Examples of the present invention will be described below in comparison with comparative examples to demonstrate the effects. These examples show one embodiment of the present invention, and the present invention is not limited thereto.

Example 1 and Comparative Example 1
The core material (C1-4, C11) having the composition shown in Table 1 and the brazing material (B1-13) having the composition shown in Table 2 are ingot-formed by continuous casting. It was chamfered to ˜27 mm (length 175 mm × width 175 mm), hot-rolled to a predetermined thickness of the brazing material, and cut into dimensions of length 175 mm × width 175 mm. In Tables 1 and 2, those outside the conditions of the present invention are underlined.

The core material is coated with a slurry of a mixture of nocollock flux (KF + AlF ₃ ) powder (partially powder consisting of 80% nocollock flux and 20% CsF) and metal powder in alcohol. The core material and the brazing material were laminated so that the mixture was sealed at the interface of the brazing material. The concave portion was formed by cutting a triangular groove having a width of 1.2 mm and a depth of 0.6 mm on the surface of the core material into a lattice shape with an interval of 2 mm. In addition, as shown in FIG. 2, about what installed the aluminum frame as a mixture outflow prevention member, the mixture was apply | coated as it was.

Prior to hot rolling the laminated core material and brazing material, the core material and the brazing material were heated to a temperature of 565 ° C. while being pressurized with a heat-resistant spring and a bolt. An atmospheric furnace was used for heating, and the temperature was raised to 540 ° C. at about 50 ° C./h. Thereafter, the temperature was raised to 120 ° C./h to a predetermined temperature and held for 30 minutes, and then the furnace was cooled to 300 ° C. The pressure applied by the heat-resistant spring was 6.5 × 10 ⁻³ MPa, and the pressure applied by fixing the bolt was 1.0 × 10 ⁻³ MPa or less.

  Subsequently, the laminated core material and brazing material are hot-rolled, then cold-rolled and finally softened to a brazing sheet having a thickness of 0.4 mm (the core material thickness of the single-sided clad: 360 μm, the core material thickness of the double-sided clad: 320 μm, brazing material thickness: 40 μm). It was confirmed that the interface of the brazing sheet contained a solidified product after the mixture of the fluoride flux and metal melted. The amount of the encapsulated mixture was calculated by the above formula.

  About the produced brazing sheet (test material) 1-26, the gap filling test was done with the following method. Tables 5 and 6 show the combinations of the clad components, the inclusion conditions of the flux and the metal powder, and the gap filling test results. In Table 6, those outside the conditions of the present invention are underlined.

Gap filling test: As shown in FIG. 3, a degreasing brazing sheet was used as a horizontal material, and a 3003 alloy plate (thickness 1 mm) was assembled as a vertical material to form a gap filling test piece. Using a nitrogen gas furnace consisting of a two-chamber furnace with a preheating chamber and a brazing chamber with an internal volume of 0.4 m ³ , the gap-filled test piece was charged into the brazing chamber and brazed at an ultimate temperature of 595 ° C. did. As brazing conditions, 20 m ³ / h nitrogen gas was fed into each chamber of the nitrogen gas furnace, and the temperature was increased from 450 ° C. to 590 ° C. under the conditions shown in Tables 5-6. The oxygen concentration in the brazing chamber at the end of heating was 16 to 24 ppm. When the temperature of the gap filling test piece reached 595 ° C. in the brazing chamber, the gap filling test piece was transferred to the preheating chamber, cooled to 550 ° C. in the preheating chamber, and then taken out and cooled in the atmosphere. The gap filling length was measured from the gap filling specimen after cooling to evaluate the fillet forming ability. Those having a gap filling length of 20 mm or more were evaluated as having good fillet forming ability.

As shown in Table 5, all of the test materials 1 to 26 according to the conditions of the present invention exhibited good fillet forming ability in the gap filling test without applying the flux. Even if the amount of flux contained in the brazing sheet is 1.33 to ² g / m ^2, it is brazed and joined, and the heating time at 450 to 590 ° C. is shortened to 4 minutes or less at the time of brazing. It was confirmed that even when the amount of the test material was as small as 0.53 g / m ² (test materials 1, 16, 20, 22, 26), a sound joint was obtained.

By installing an aluminum frame as a mixture outflow prevention member around the interface where the mixture was applied, the molten flux and the metal powder could be joined without flowing out even when a strong pressure was applied by a heat-resistant spring. About what used the flux which consists of 80% of nocollock flux and CsF20% by the molar ratio (test material 10), joining at 550 degreeC was possible. Further, when the amount of flux in the encapsulated mixture was less than 1 g / m ² , the flux residue after brazing was so small that it was difficult to observe with the naked eye.

On the other hand, as shown in Table 6, the test material 27 in which the mixture was not encapsulated and the flux (Nocolok flux, the same applies hereinafter) was not applied even during brazing, and the flux was applied at 1 g / m ² during brazing. Only the test material 28 was inferior in fillet forming ability in the gap filling test. In order to obtain a good fillet forming ability, it was necessary to apply a flux of ² to 3 g / m ² during brazing (test materials 29 and 30).

  Since the test material 31 has a large amount of Mg in the core material, the test material 32 has a large amount of Mg in the brazing material, and the test material 33 has a small amount of Si in the brazing material, both have poor fillet forming ability in the gap filling test. In No. 34, since the amount of Si in the brazing material was large, the core material was excessively melted in the gap filling test.

Example 2
Using the ingot of the core material and the brazing material in Example 1, the core material is face-cut to a thickness of 26 to 27 mm (175 mm length × 175 mm width) as in Example 1, and the brazing material has a predetermined thickness. It was hot-rolled and cut into dimensions of 175 mm long x 175 mm wide.

The clad component material is formed by laminating a two-layer brazing material comprising a first layer brazing material and a second layer brazing material on the core material, an interface between the first layer brazing material and the second layer brazing material, and a second layer brazing material and the core material. In order to enclose a mixture of a fluoride-based flux and a metal at the interface, nocollock flux (KF + AlF ₃ ) powder and Al-10% Si-35% Zn powder are formed on the surface of the second layer brazing material and the surface of the core material. A mixture of the mixture dissolved in alcohol to form a slurry was applied, and a core material and a brazing material (first layer brazing material and second layer brazing material) were laminated. In addition, about what installed the aluminum frame as a mixture outflow prevention member, the mixture was apply | coated as it was.

Prior to hot rolling the two-layer brazing material consisting of the first layer brazing material and the second layer brazing material on the core material, the laminated core material and brazing material are pressed by heat-resistant springs and bolts. While heating to a temperature of 565 ° C. As in Example 1, an atmospheric furnace was used for heating, and the temperature was raised to about 540 ° C. at about 50 ° C./h. Thereafter, the temperature was raised to 120 ° C./h to a predetermined temperature and held for 30 minutes, and then 300 ° C. The inside of the furnace was cooled. The pressure applied by the heat-resistant spring was 6.5 × 10 ⁻³ MPa, and the pressure applied by fixing the bolt was 1.0 × 10 ⁻³ MPa or less.

  Next, the laminated core material and brazing material (first layer brazing material and second layer brazing material) are hot-rolled, and then cold-rolled and finally softened to form a brazing sheet (core material thickness) of 0.4 mm. : 360 μm, first layer brazing material thickness: 12 μm, second layer brazing material thickness: 28 μm). It was confirmed that the interface of the brazing sheet contained a solidified product after the mixture of the fluoride flux and metal melted. The amount of the encapsulated mixture was calculated by the above formula.

  About the produced brazing sheet (test material) 35-41, the gap filling test was done by the same method as Example 1. Table 7 shows the combination of clad components, the inclusion conditions of flux and metal powder, and the gap filling test results.

  As shown in Table 7, all of the test materials 35 to 41 according to the conditions of the present invention exhibited good fillet forming ability in the gap filling test without applying flux.

Example 3
Ingot of core material ingot in Example 1, ingot of brazing material, intermediate material (A1) having composition shown in Table 3 ingot by continuous casting, and skin material (S1) having composition shown in Table 4 In the ingot, the core material is chamfered to a thickness of 26 to 27 mm (length 175 mm × width 175 mm), and the brazing material, intermediate material and skin material are hot-rolled to a predetermined thickness, and length 175 mm × width 175 mm. Cut to dimensions.

The clad constituent material shall be formed by laminating a brazing material on one side of the core material through an intermediate material, and laminating a skin material on the other side of the core material, the interface between the brazing material and the intermediate material, the interface between the intermediate material and the core material, In order to enclose a mixture of fluoride-based flux and metal at the interface between the base material and the skin material, nocollock flux (KF + AlF ₃ ) powder and Al-10% Si-35% Zn powder are formed on the surface of the intermediate material and both surfaces of the core material. A mixture obtained by dissolving the mixture in alcohol to form a slurry was applied to laminate a brazing material, an intermediate material, a core material, and a skin material.

Prior to hot rolling, the laminated core material, intermediate material and brazing material were heated to a temperature of 565 ° C. while being pressed by bolt fixing. As in Example 1, an atmospheric furnace was used for heating, and the temperature was raised to about 540 ° C. at about 50 ° C./h. Thereafter, the temperature was raised to 120 ° C./h to a predetermined temperature and held for 30 minutes, and then 300 ° C. The inside of the furnace was cooled. In addition, the applied pressure by bolt fixation was 1.0 * 10 < ^-3 > MPa or less.

  Subsequently, the laminated brazing material, intermediate material, core material and skin material are hot-rolled, and then cold-rolled and finally softened to a brazing sheet having a thickness of 0.4 mm (brazing material thickness: 12 μm, intermediate material thickness). (S: 28 μm, core material thickness: 320 μm, skin material thickness: 40 μm). It was confirmed that the interface of the brazing sheet contained a solidified product after the mixture of the fluoride flux and metal melted. The amount of the encapsulated mixture was calculated by the above formula.

  The produced brazing sheet (test material) 42 was subjected to a gap filling test by the same method as in Example 1. Table 8 shows the combination of the clad components, the inclusion conditions of the flux and the metal powder, and the gap filling test results.

  As shown in Table 8, the test material 42 according to the conditions of the present invention showed a good fillet forming ability in the gap filling test without applying flux.

DESCRIPTION OF SYMBOLS 1 Mixture (of flux and metal powder) 2 Mixture outflow prevention member 3 Wide part 4 Aluminum frame (made of aluminum extruded profile) t Thickness of mixture outflow prevention member 2 h Height of mixture outflow prevention member 2

Claims (14)

A brazing sheet used in a heat exchanger that is brazed and joined by heating without applying a flux in an inert gas atmosphere, and Si: 6 to 13% (mass%) on one or both sides of the core , The same shall apply hereinafter), and clad with an Al—Si aluminum alloy brazing material (hereinafter referred to as brazing material). At the interface between the core material and the brazing material, a fluoride flux and a solidus temperature of 565 ° C. or less. An aluminum alloy brazing sheet characterized in that a mixture with metal powder is contained, and a part or all of the mixture is melted and then solidified. The Mg content of the brazing material and the core material is limited to 0.05% or less, and the amount of flux in the mixture contained in the interface is 2.0 g / m ² or less. The aluminum alloy brazing sheet according to 1. 3. The aluminum alloy according to claim 1, wherein the brazing material further contains one or two of Zn: 0.5 to 10% and Cu: 0.2 to 3.0%. Brazing sheet. A brazing sheet used in a heat exchanger that is brazed and bonded by heating without applying a flux in an inert gas atmosphere, and Al containing Si: 6 to 13% on one or both sides of a core material A mixture of a fluoride flux and a metal powder having a solidus temperature of 565 ° C. or less is formed at the interface between the brazing material and the brazing material clad in two layers. An aluminum alloy brazing sheet which is encapsulated and part or all of the mixture is melted and then solidified. A mixture of a fluoride-based flux and a metal powder having a solidus temperature of 565 ° C. or less is contained in the interface between the brazing material and the brazing material and the interface between the core material and the brazing material, and a part of the mixture or The aluminum alloy brazing sheet according to claim 4, wherein the aluminum alloy brazing sheet is solidified after all is melted. The Mg content of the brazing material clad in the two layers is limited to 0.05% or less, the Mg content of the core material is limited to 0.05% or less, and the mixture contained in the interface The aluminum alloy brazing sheet according to claim 4 or 5, wherein the flux amount of the aluminum alloy is 2.0 g / m ² or less. Either or both of the brazing materials clad in the two layers further contain one or two of Zn: 0.5 to 10% and Cu: 0.2 to 3.0%. The aluminum alloy brazing sheet according to any one of claims 4 to 6. A brazing sheet used in a heat exchanger that is brazed and bonded by heating without applying a flux in an inert gas atmosphere, and an intermediate of an aluminum alloy containing Si: less than 6% on one side of a core material An Al—Si brazing material containing Si: 6 to 13% is clad through the material, and an aluminum alloy skin is clad on the other side of the core material, and at the interface between the aluminum alloy brazing material and the intermediate material. Is characterized in that it contains a mixture of a fluoride-based flux and a metal powder having a solidus temperature of 565 ° C. or less, and a part or all of the mixture is melted and solidified. Alloy brazing sheet. The Mg content of the brazing material, intermediate material, core material and skin material is limited to 0.05% or less, and the amount of flux in the mixture contained in the interface between the brazing material and the intermediate material is 2.0 g / m ^2. The aluminum alloy brazing sheet according to claim 8, wherein: One or both of the brazing material and the intermediate material further contain one or two of Zn: 0.5 to 10% and Cu: 0.2 to 3.0%. The aluminum alloy brazing sheet according to any one of claims 8 to 9. A method for producing an aluminum alloy brazing sheet according to any one of claims 1 to 10, wherein a core material and a brazing material are laminated as a clad constituent material, or a core material, an intermediate material, a brazing material and a skin material are laminated. In addition, a mixture of a fluoride-based flux and metal powder is included in the interface, and when performing hot clad rolling, prior to hot clad rolling, the laminated clad constituent material is heated and bonded while being pressed. A method for producing an aluminum alloy brazing sheet. When laminating the core material and the brazing material, or the core material, the intermediate material, the brazing material and the skin material as the clad constituent material, a recess is provided in the interface, and a fluoride flux and a solidus temperature are provided at the interface. A mixture with a metal powder of 565 ° C. or lower is placed, and the clad constituent material laminated in a state of sandwiching the mixture is pressurized and heated, so that a part or all of the mixture is melted and joined. The method for producing an aluminum alloy brazing sheet according to claim 11, wherein clad rolling is performed. The method for producing an aluminum alloy brazing sheet according to claim 11 or 12, wherein a mixture outflow prevention member is provided so as to surround a periphery of an interface for sandwiching the mixture. The aluminum alloy brazing sheet according to any one of claims 1 to 10, wherein a flux amount in the mixture included in the interface is set to 1.0 g / m ² or less, and is assembled in an inert gas atmosphere. A method for brazing an aluminum heat exchanger, wherein heating is performed with a temperature rising time from 450 ° C. to 590 ° C. within 4 minutes without applying a flux.

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