JP5490603B2 - Brazing method of aluminum member - Google Patents

Description

  The present invention relates to a method for brazing an aluminum alloy that does not use a flux, and in particular, relates to a method for producing a brazed product with high hermeticity using a brazing wax.

  Aluminum materials are frequently used in heat exchangers such as automobiles because of their high thermal conductivity and light weight. With regard to heat exchangers that allow heat exchange to function by flowing a coolant such as water, there are many heat exchangers composed of tanks, tubes, and fins. The refrigerant is sent from the tank to the tube, and releases heat to the outside of the heat exchanger through fins that come into contact with the tube. The heat exchanger that flows the refrigerant does not perform its function when the refrigerant leaks from the heat exchanger, and therefore needs to have a sealed structure. For this reason, the tank, tubes and fins constituting the heat exchanger are joined metallically by brazing, and the gap is completely filled with the brazing material at the part where each member contacts.

  As the aluminum material constituting the heat exchanger manufactured by brazing, a brazing sheet in which a brazing material or the like is clad on one side or both sides of a core material is used. Generally, an aluminum alloy having a solidus temperature of 600 ° C. or more is used as the core material alloy of the brazing sheet, and an Al—Si alloy having a liquidus temperature of 600 ° C. or less as the brazing filler metal alloy to be clad. Is used. By producing and combining the members of the heat exchanger with this brazing sheet and heating to a temperature around 600 ° C., only the brazing filler metal part of the brazing sheet is melted and brazed to other members, and between each member By filling the gap with the brazing material, a heat exchanger having a hermetic structure can be manufactured.

  Brazing methods that are mainly put to practical use include vacuum brazing and noclock brazing. The vacuum brazing method uses a brazing material made of an Al-Si-Mg alloy. When heated in a vacuum, Mg in the brazing material evaporates from the material, and at that time, the oxide film on the surface of the material is destroyed. It is possible to braze. However, the vacuum brazing method has a drawback of requiring an expensive vacuum heating device.

  On the other hand, the Nocolok brazing method uses a brazing material made of an Al-Si alloy. By applying the flux and heating it in an inert gas, the oxide film on the surface of the material is destroyed by the flux and brazing is possible. It is to make. In the Nocolok brazing method, the wettability of the brazing material is good due to the action of the flux, and the filling property of the gap is excellent due to the brazing material. However, if flux coating unevenness occurs in the flux application process, it causes brazing failure, and it is indispensable to uniformly apply the flux to the necessary portions.

  For these methods, a brazing method has been proposed that enables brazing by heating in an inert gas without using a flux. Patent Document 1 describes a method in which a brazing product containing Mg is covered with a carbonaceous cover, heated, and brazed without using a flux. This method enables brazing by reducing the oxygen concentration in the carbonaceous cover with Mg and preventing oxidation. Patent Document 2 describes a method in which a heat exchanger is configured using a clad material containing Mg as a brazing material, and brazing is performed without using a flux. This method enables brazing by removing the oxide film on the surface with Mg in the brazing material.

JP 2007-044713 A JP 2007-190574 A

  For example, in a heat exchanger that has a structure in which a tube is inserted into a tank, a hole for inserting the tube is provided in the tank, and the tube is inserted into the hole to form a heat exchanger. A heat exchanger is manufactured by filling with wood. When the gap between the tank and the tube is as small as possible, high sealing performance by the brazing material can be obtained. However, when manufacturing a heat exchanger industrially, there is a limit to reducing the gap, and it is necessary to seal a gap of a certain size with a brazing material. However, in both methods of Patent Documents 1 and 2, the destructive force of the oxide film is weak, the fluidity of the brazing material is low, and it is difficult to fill the gaps with wax. For this reason, voids are easily generated in the gap, and there is a possibility that the sealing performance is impaired.

  In order to ensure the filling property of the brazing material in the gap, a method of reducing the gap of the joint portion or a method of increasing the brazing material amount of the brazing sheet is generally effective. However, the joint gap cannot be completely eliminated due to the processing limit of the material. Further, if the clad rate of the brazing material is increased in order to increase the brazing material amount of the brazing sheet, it becomes difficult to press the brazing material and the brazing material, so there is a limit to the increase in the brazing material amount of the brazing sheet.

  In order to use the brazing material clad on the brazing sheet for brazing as effectively as possible, there is also a method of suppressing the diffusion of the brazing material into the core material in the brazing sheet and increasing the amount of the brazing material flowing. For this purpose, it is necessary to control the strain amount of the core material, but it is difficult to stably control the strain amount in the brazing sheet processed into various shapes.

  When filling the gap with brazing material and securing the sealing performance like the joint between tank and tube described above, if the brazing amount of brazing sheet alone is insufficient, place the brazing on the brazing part. There is a way to increase the amount of brazing material. However, in the brazing method using a brazing sheet containing Mg and not using a flux, it was difficult to fill the gap portion by placing it.

  An object of the present invention is to provide a brazing method having a high hermeticity by improving the filler filling property of the gap in the joint in brazing in an inert gas without using a flux.

  As a result of intensive studies in view of the above problems, the present inventors have conducted brazing without using a flux using a brazing sheet containing Mg. It has been found that by controlling the Mg content of the brazing filler to be filled, when the Mg content in the gap after the brazing addition heat becomes a specified amount, the filling property of the brazing material in the gap is improved.

  The present invention is the method according to claim 1, wherein the first member composed of an aluminum alloy brazing sheet and the second member composed of aluminum or an aluminum alloy (hereinafter referred to as "aluminum material") are brazed. And at least one portion constituting the brazing sheet made of aluminum alloy contains Mg, and an Al-Si based aluminum alloy placing wax is disposed in the gap between the first member and the second member. Heating in an inert gas without applying flux, brazing both members, and after brazing, the Mg content of the brazing material filled in the gap is 75% or less of the Mg content of the brazing material other than the gap It was set as the brazing method of the aluminum member characterized by becoming.

  The present invention is the method of brazing the first member composed of the aluminum alloy brazing sheet and the second member composed of the aluminum material according to claim 2, wherein the aluminum alloy brazing sheet comprises: Mg: 0.2 to 1.0 mass% and the balance Al and an inevitable impurity Al-Mn based aluminum alloy is used as a core, Si: 5 to 13 mass%, Mg: 0.05 mass on one or both sides of the core %, And the balance between the first member and the second member is Si: 5 to 5%. Al-Si-based aluminum alloy containing 13 mass%, Mg: 0.2 mass% or less, the balance being Al and inevitable impurities It is placed and heated in an inert gas without applying flux, and both members are brazed, and after brazing, the Mg content of the brazing filler filled in the gap is 75 of the Mg content of the brazing filler other than the gap. % Or less, a brazing method for an aluminum member.

  The present invention is the method of brazing the first member composed of the aluminum alloy brazing sheet and the second member composed of the aluminum material according to claim 3, wherein the aluminum alloy brazing sheet is made of Al. -An Al-Si-based aluminum alloy comprising a Mn-based aluminum alloy as a core material and containing Si: 5 to 13 mass%, Mg: 0.2 to 1.5 mass% on one or both surfaces of the core material, and the balance Al and inevitable impurities The brazing material is clad, and the surface of the brazing material is further clad with an aluminum alloy skin material containing Mg: 0.05 mass% or less and the balance Al and unavoidable impurities. The gap between the member and the second member contains Si: 5 to 13 mass%, Mg: 0.2 mass% or less, and the balance Al and non Place an Al-Si-based aluminum alloy brazing filler made of evasive impurities, heat in an inert gas without applying flux, braze both members, and braze filler filled in the gap after brazing A method for brazing an aluminum member, characterized in that the Mg content is 75% or less of the Mg content of the brazing material other than the gap.

  Here, the brazing material other than the gap refers to the brazing material that does not flow into the gap and remains on the surface of the brazing sheet. That is, it is a brazing material in a portion where the brazing material thickness after brazing is not increased more than the brazing material thickness before brazing, and is a brazing material that is hardly mixed with the brazing.

  By performing the brazing method according to the present invention, it is possible to produce a brazed product without using a flux. In producing a brazed product in which a gap at a joint is filled with a brazing material and sealed, It is possible to increase production efficiency and secure stable brazing.

It is explanatory drawing which shows the brazing method which concerns on this invention. It is explanatory drawing which shows the state after brazing.

The present invention is described in detail below.
For brazing aluminum according to the present invention, a first member made of a brazing sheet provided with a brazing material that is a bonding material, and a second member made of an aluminum material that is a member to be bonded to be brazed thereto In addition, a brazed assembly comprising a placing brace disposed in the gap between the two is used. Then, the oxide film present on the surfaces of the first member, the second member, and the placing brazing is destroyed by some method, and the brazing material of the first member and the second member are brazed to be joined metallically. To do. In conventional brazing in an inert gas, a flux is used to break the oxide film. The flux destroys the oxide film by a chemical reaction. On the other hand, the brazing method of the present invention performs brazing by heating in an inert gas using the first member containing Mg without applying flux. Mg contained in the first member reduces the oxide film existing on the surface of the brazing material and the brazing filler metal of the first member and the surface of the second member into brazing addition heat and destroys it. . As a result, the first member and the second member can be metallically joined by brazing. In the present invention, the content of Mg contained in the first member is 0.001% or more, preferably 0.1% or more.

A. Function and filling performance of brazing When there is a gap in the brazing part, the brazing sheet's oxide film is sufficiently destroyed, the brazing material has sufficient fluidity, and the brazing material is supplied from the part away from the gap If possible, the gap can be filled with wax. However, there is a case where a brazing material sufficient to fill a large gap cannot be supplied only by the action of only the oxide film destruction by Mg contained in the brazing sheet. In that case, it is necessary to supply an additional brazing material for filling the gap, and in the present invention, the brazing material is supplied by brazing.

  When the brazing filler fills the gaps of the gap constituent members and is metallically joined, the oxide film present on the brazing filler metal surface needs to be destroyed. The oxide film of the placing wax is reduced and destroyed by Mg in the brazing sheet. In the present invention, the presence of Mg is indispensable, but if excessive Mg is present in the wax to be placed, the brazeability is lowered. This is because a strong oxide film of magnesium is formed on the surface of the brazing before brazing or during brazing temperature rising. Once formed, the magnesium oxide film can no longer be reduced and destroyed by Mg in the material. The magnesium oxide film remaining in the brazing addition heat hinders the fluidity of the molten brazing filler and often causes voids in the gap. Therefore, it is necessary to make the Mg content of the brazing filler filled in the gap smaller than the Mg content of the brazing material of the brazing sheet other than the gap.

  Therefore, as a result of investigating the Mg content after brazing in the gap in various joining states, the inventors have found that if the Mg content of the brazing material other than the gap is 75% or less, the fluidity of the brazing filler is hindered. It was found that good gap filling properties can be achieved without being formed and without voids occurring in the gap. When the Mg content of the brazing filler metal in the gap exceeds 75% of the Mg content of the brazing filler metal other than the gap, oxidation of Mg contained in the brazing filler metal proceeds. As a result, the flowability of the brazing filler is hindered, voids are generated in the gap, and the filling performance of the wax in the gap is lowered.

B. Two-layer or three-layer brazing sheet The aluminum alloy brazing sheet, which is the first member used in the present invention, is a two-layer brazing sheet in which a core material containing Mg and a brazing material are clad on one side in the first embodiment. Or a three-layer brazing sheet clad with a brazing material on both sides. Mg contained in the core material has an important influence on the brazing property. That is, Mg contained in the core material diffuses into the brazing material during the brazing heat, and reduces and destroys the oxide film on the brazing material surface and the aluminum oxide film on the brazing filler metal while evaporating from the brazing material surface when the brazing material melts. Thus, brazing with the second member is achieved. Further, Mg diffuses during placing, so that brazing between the placing member and the second member can be promoted. The clad rate of the brazing material is 2.5 to 30% on one side, and the thickness of the brazing sheet is 0.4 to 3.5 mm. Such a brazing sheet can be used for the tank wall of a heat exchanger, for example.
The brazing sheet is produced by the following method. After the core material and the brazing material alloy are subjected to normal DC casting, the brazing material is rolled to a predetermined thickness by hot rolling. The core material and the brazing material are superposed and pressure-bonded by hot rolling, and further rolled to a predetermined thickness by cold rolling.

B-1. Core Material In the first embodiment of the present invention, the core material contains Mg: 0.2 to 1.0 mass% (hereinafter, simply referred to as “%” in the components), and the balance Al and Al composed of inevitable impurities. -A Mn alloy is used. If the Mg content of the core material is less than 0.2%, the Mg content diffusing into the brazing material will be insufficient. As a result, the brazing material and the oxide film of the brazing filler metal cannot be sufficiently reduced and destroyed, and the brazing property is lowered. On the other hand, if the Mg content exceeds 1.0%, the amount of Mg diffused from the core material to the brazing filler metal or the brazing filler will be excessive, and magnesium oxide will be formed on the brazing filler metal or the brazing filler metal surface, thereby reducing the brazeability. . Further, the Mn content of the core material is preferably 0.2 to 1.6%. If the content is less than 0.2%, the strength is insufficient, and if it exceeds 1.6%, the moldability is lowered.

B-2. Brazing material In the first embodiment of the present invention, the brazing material is an Al—Si alloy containing Mg: 0.05% or less, Si: 5-13, and the balance being Al and inevitable impurities. By making Mg 0.05% or less, there is almost no Mg oxide on the brazing filler metal surface during the temperature rise of brazing, so there is almost no production of magnesium oxide, and the brazing filler metal surface is almost an aluminum oxide film. Occupied. Therefore, the aluminum oxide film is reduced and broken by Mg diffused from the core material when the brazing material is melted, and brazing becomes possible. On the other hand, if the Mg content exceeds 0.05%, magnesium oxide is generated on the surface of the brazing material during the temperature rise during the brazing addition heat. This magnesium oxide becomes a thick oxide film when it reaches a temperature at which the brazing material melts and cannot be brazed. Further, when the Si content is less than 5%, a sufficient amount of the molten brazing material is not generated, and when it exceeds 13%, the erosion of the core material becomes remarkable and the brazing property is lowered.

  Even if the core material and brazing material contain 0.05% or less of each component as an unavoidable impurity and 0.15% or less of Fe, Cu, Ti or the like as a total amount, the performance is not hindered. .

C. Three-layer or five-layer brazing sheet The aluminum alloy brazing sheet, which is the first member used in the present invention, is clad with a core material and a brazing material containing Mg on one or both sides thereof in the second embodiment, It is a three-layer or five-layer brazing sheet in which a skin material is clad on the surface of a brazing material. That is, it is a brazing sheet of 3 layers of skin material / brazing material / heart material or 5 layers of skin material / brazing material / heart material / brazing material / skin material. In this embodiment, the Mg source that contributes to brazing is not the core material of the brazing sheet but the brazing material. Therefore, compared with the first embodiment, the Mg content in the core material is small, and the Mg content in the brazing material is increased. The clad rate of the brazing material is 2.5 to 30% on one side, and the clad rate of the skin material is 0.1 to 10% on one side. The thickness of the brazing sheet is 0.4 to 3.5 mm. The brazing sheet is produced by the following method. After the core material, the brazing material and the skin alloy are subjected to normal DC casting, the brazing material and the skin material are rolled to a predetermined thickness by hot rolling. Manufactured by superposing core material, brazing material and skin material, pressing them by hot rolling, and rolling them to a predetermined thickness by cold rolling.

C-1. Core Material In the second embodiment of the present invention, an Al—Mn alloy is used as the core material. The Mn content of the core material is preferably 0.2 to 1.6%. If the Mn content is less than 0.2%, the strength is insufficient, and if it exceeds 1.6%, the moldability is lowered.

C-2. Brazing material In the second embodiment of the present invention, the brazing material contains Mg: 0.2 to 1.5%, Si: 5 to 13, and an Al—Si alloy composed of the balance Al and inevitable impurities is used. It is done. If the Mg content is less than 0.2%, the brazing material and the oxide film on the brazing filler metal surface cannot be sufficiently reduced and destroyed, and the brazing property is lowered. On the other hand, if the Mg content exceeds 1.5%, magnesium oxide is generated on the surface of the brazing material during the temperature rise when the brazing sheet is subjected to brazing addition heat. This magnesium oxide becomes a thick oxide film when it reaches a temperature at which the brazing material melts and cannot be brazed. Further, the amount of Mg diffused from the brazing material to the placing wax becomes excessive, and magnesium oxide is formed on the surface of the placing wax, so that the brazing property is lowered. Further, when the Si content is less than 5%, a sufficient amount of the brazing filler metal is not generated, and when it exceeds 13%, the erosion of the core material becomes remarkable and the brazing property is lowered.

C-3. Skin Material In the second embodiment of the present invention, the skin material functions as an antioxidant layer on the surface of the brazing material during the temperature rise until the brazing material is melted. That is, when the brazing material is melted by the brazing heat, the brazing material is broken and the brazing material is exposed, so that brazing can be performed without using the flux. Mg contained in the brazing material reduces and destroys the oxide film of the second member, and also enables brazing for destroying the oxide film of the placing braze and metallically joining. Furthermore, Mg diffuses during placing, and brazing of the second member can be promoted. The skin material is made of an aluminum alloy containing 0.05% or less of Mg. If it exceeds 0.05%, magnesium oxide is formed on the surface of the skin material, so that the brazing property is lowered.

  In addition, the core material, the brazing material, and the skin material have performance of 0.05% or less as each component and 0.15% or less as a total amount as an unavoidable impurity. Will not be disturbed.

  The skin material thickness is preferably 5 to 50 μm. When the thickness is less than 5 μm, Mg in the brazing material diffuses in the skin material in a short time, and magnesium oxide is formed on the surface of the skin material before the brazing material melts, which may reduce brazing. When the thickness of the skin material exceeds 50 μm, even if the brazing material melts, the skin material is broken and the brazing material becomes difficult to be exposed, and the brazing property may be lowered.

D. The brazing filler used in the present invention is an Al-Si based aluminum alloy in which the Mg content is limited to 0.2 mass% or less, the Si content is 5 to 13 mass%, and the balance is Al and inevitable impurities. it can. Furthermore, the Mg content is more preferably 0.05 mass% or less. In order for the molten brazing filler material to fill the gap, it is necessary to destroy the oxide film of the second member with Mg. In the present invention, Mg is supplied from the brazing sheet during brazing addition heat, so the Mg content in the brazing filler is 0.2% or less. If it exceeds 0.2%, the formation of magnesium oxide on the surface of the brazing will become remarkable, and the brazing property will deteriorate. The Si content in the placing wax is 5 to 13%. If the Si content is less than 5%, a sufficient amount of molten brazing material will not be produced, and if it exceeds 13 mass%, Si erosion from the placed solder to the member will be remarkable and good brazing will not be obtained, and the manufacturability will also be improved. descend.

  To put it, Fe, Cu, Zn or the like may be added in which each component is 6% or less as an additive component other than Mg and Si. Furthermore, even if it contains 0.05% or less of each component as an inevitable impurity and 0.15% or less of Ti, Bi or the like as a total amount, the performance is not hindered. The placing wax can take the form of a wire, foil, etc., which are processed into a necessary shape and installed in the joint. In the manufacturing method, after casting the brazing alloy, the brazing wire is drawn by drawing, and the brazing foil is produced by rolling to a predetermined size.

E. 2nd member comprised from aluminum material The 2nd member comprised from the aluminum material used for this invention is filled with the brazing sheet made from the aluminum alloy which is the above-mentioned 1st member, and the clearance gap with a brazing material. So that it is brazed. The material of the second member is a pure aluminum material or an aluminum alloy such as an Al—Mn alloy or an Al—Zn alloy. Such a 2nd member is used as a tube material of a heat exchanger, for example. In the present invention, the third member may be brazed to at least one of the first member and the second member simultaneously with the brazing of the first member and the second member. For example, the first member is a heat exchanger tank material, the second member is a heat exchanger tube material, the third member is a corrugated fin material, and the first and second members are brazed. Then, the assembly for brazing is produced by sandwiching the corrugated fin material between the tubes and brazing the tube, and then the heat exchanger is produced by brazing the assembly. Is.

F. Brazing Brazing may be performed by heating to a temperature equal to or higher than the melting temperature of the brazing material. In the present invention, brazing can be performed by heating to 590 to 610 ° C. A holding time of 3 to 10 minutes is appropriate. An inert gas is used as the atmosphere for brazing addition heat. Examples of the inert gas include industrially used nitrogen gas and argon gas. In order to enable brazing, it is appropriate that the oxygen concentration in the atmosphere is 250 ppm or less, and stable brazing is possible when the oxygen concentration is lower. Also in the present invention, it is necessary to reduce the oxygen concentration in the atmosphere as much as possible and to suppress the oxidation of Mg as much as possible to improve the brazing property.

  In order to obtain a low oxygen atmosphere, it is desirable to use a brazing additive heating furnace using a carbon material as a constituent member of the furnace that comes into contact with the inert gas in the brazing furnace. Examples of such components include a furnace inner wall, a baffle, a mesh belt for conveying a brazing object, and the like. Since the carbon material reacts with a small amount of oxygen in the non-oxidizing gas to generate CO, the oxygen concentration in the furnace can be lowered. When brazing with an existing brazing furnace, a method of separately installing a carbon material in the furnace is also possible.

  Further, a small amount of oxygen mixed into the furnace is often taken in mainly by the brazing material. In particular, when the brazed object has a hollow structure like a heat exchanger, oxygen existing inside is not sufficiently replaced, which hinders reduction of the oxygen concentration in the furnace atmosphere. Therefore, a low oxygen atmosphere can be achieved during brazing heating by using a brazing furnace including a plurality of furnace chambers including a preheating chamber and a brazing additional heat chamber and sufficiently reducing the oxygen concentration during preheating. In addition, after inserting the brazing object, the inside of the furnace is evacuated and then a non-oxidizing gas is blown to prevent an increase in the oxygen concentration in the furnace. Furthermore, by using a brazing furnace equipped with an atmospheric gas replacement device, industrially more stable brazing properties can be obtained.

  Next, the present invention will be described in detail based on examples and comparative examples.

  An alloy of brazing sheet core material, brazing material, and skin material component was manufactured by die casting, and the surface was chamfered to a thickness of 50 mm. The brazing material and the skin material were preheated at 510 ° C. for 1 hour, and then hot-rolled to a predetermined thickness. Prepare two-layer brazing sheet clad with cast core material and brazing material, or three-layer brazing sheet with clad core material, brazing material and skin material, preheat at 480 ° C for 1 hour, hot rolling To 3 mm. Furthermore, after performing cold rolling to 1 mm, annealing was performed at 380 ° C. for 3 hours to produce a brazing sheet made of aluminum alloy having a plate thickness of 1 mm. Tables 1 and 2 show the composition of the brazing sheet, the clad rate, the alloy composition of the core material, the brazing material, and the skin material.

  The brazing sheet produced as described above was cut into 50 mm squares. As shown in FIG. 1, the cut brazing sheet 1 was imitated on a tank wall of a heat exchanger (first member). In the example shown in FIG. 1, the brazing sheet 1 is a two-layer brazing sheet in which a brazing material 2 is clad on one side of a core material 3. A hole 10 having a diameter of 10.2 mm is provided in the center of the brazing sheet 1. A JIS A3003 pipe having a diameter of 10 mm and a wall thickness of 1 mm was prepared and imitated as a tube 4 of a heat exchanger (second member). The tube 4 was inserted into the hole 10 of the brazing sheet 1 and a wax 5 was placed in the gap. As the placing wax 5, a brazing wire was used. For the brazing wire, an alloy having the components shown in Table 3 was cast to prepare an inch bar, which was drawn to φ1.0 mm, and further annealed at 380 ° C. for 3 hours to obtain a brazing wire. The brazing material 2 was placed on the brazing material 2 surface, which is the inner surface of the brazing sheet 1, along the outer circumferential surface of the tube 4, and the brazing material 5 was wound once around. In this way, a sample simulating the tank of the heat exchanger and the brazed part of the tube was produced.

  The prepared sample was brazed without applying flux. Brazing was performed by heating in a furnace in which nitrogen gas was passed as an inert gas in the furnace and the oxygen concentration in the furnace was adjusted to 30 ppm or less. The temperature of the sample was measured. After the sample temperature reached 600 ° C., this temperature was maintained for 5 minutes, and then cooled and taken out of the furnace.

The following evaluation was performed on the sample after brazing.
(1) Fillet formation state As shown in FIG. 2, the fillet formation state was observed from the appearance. A case where a fillet 6 having a stable size was formed over the entire circumference was marked with (◯), and a fillet was formed over the whole circumference but the size of the fillet was small (Δ), and a brazed piece was generated. The thing was set as (x). ○ and Δ were accepted and x was rejected.

(2) Fillet length As shown in FIG. 2, the cross section of the brazing part was observed about the sample whose fillet formation state passed. The fillet length 7 in the fillet 6 was a distance at which the wax wetted and spread on the tube 4 on the basis of the brazing sheet surface after brazing.

(3) Mg content As shown in FIG. 2, the Mg content in the brazing material inside 8 at the flat part of the brazing sheet (Mg content in the brazing material other than the gap) and the Mg content in the brazing material inside 9 of the fillet 6. (Mg content of brazing filler filled in gap) was measured by EPMA.

  Brazing sheets and brazing sheets shown in Tables 1 to 3, fillet formation state, fillet length, Mg content (A) inside brazing material of brazing sheet flat part, Mg content (B) inside brazing material of fillet, B / A (%) is shown in Tables 4 and 5.

  In Examples 1 to 33, there are no occurrences of brazing in the fillet, and the Mg content of the brazing material filled in the gap after brazing is 75% or less of the Mg content of the brazing material other than the gap (B / A was 75% or less) and good brazing was obtained.

(Comparative Example 34 to Comparative Example 37)
In these comparative examples, the brazing filler does not contain Mg, and shows the influence of the Mg amount of the core material of the brazing sheet or the Si amount and Mg amount of the brazing material.
In Comparative Example 34, since the Mg content in the core material and the brazing material of the two-layer brazing sheet was too small, no fillet was formed and brazing could not be performed even when the brazing was placed.
A pad was not formed and could not be brazed.
In Comparative Example 35, since the Si content of the brazing material of the two-layer brazing sheet was too large, no fillet was formed and brazing could not be performed.
In Comparative Example 36, since the brazing material of the three-layer brazing sheet contained too much Si, no fillet was formed and brazing could not be performed.
In Comparative Example 37, since the Mg content of the brazing material of the three-layer brazing sheet was too low, no fillet was formed and brazing could not be performed.

(Comparative Example 38 to Comparative Example 42)
These comparative examples show the influence of the amount of Mg and the amount of Si in the two-layer brazing sheet.
In Comparative Example 38, the fillet was not formed because the Si content of the brazing filler was too low, and the B / A exceeded 75 and the brazing property was poor.
In Comparative Example 39, since the Si content of the brazing filler was too much, fillets were not formed, and B / A exceeded 75 and the brazing property was poor.
In Comparative Example 40, since the Mg content in the brazing filler was too much, fillets were not formed, and B / A exceeded 75 and the brazing property was poor.
In Comparative Example 41, since the Mg content of the brazing filler was too much, no fillet was formed, and B / A exceeded 75 and the brazing property was poor.
In Comparative Example 42, no placer was installed, so no fillet was formed, and B / A exceeded 75 and the brazeability was poor.

(Comparative Example 43 to Comparative Example 45)
These comparative examples show the influence of the amount of Mg in the three-layer brazing sheet.
In Comparative Example 43, there was too much Mg content in the wax so that no fillet was formed, and B / A exceeded 75 and the brazing property was poor.
In Comparative Example 44, the fillet was not formed because the Mg content of the brazing filler was too much, and the B / A exceeded 75 and the brazing property was poor.
In Comparative Example 45, no placer was installed, so no fillet was formed, and B / A exceeded 75 and the brazeability was poor.

  According to the brazing method of the present invention and the brazed assembly used therefor, it is possible to manufacture a brazed product without using a flux, and the gap between the joints is filled with a brazing material and sealed. In producing a brazed product, it is possible to ensure stable brazing with high production efficiency.

DESCRIPTION OF SYMBOLS 1 Brazing sheet 2 Brazing sheet brazing material 3 Brazing sheet core material 4 Tube material 5 Place brazing 6 Fillet 7 Fillet length 8 Mg content analysis position inside brazing material of brazing sheet flat part 9 Mg content inside brazing material of fillet Quantitative analysis position 10 Blazing sheet hole

Claims (3)

  A method of brazing a first member composed of an aluminum alloy brazing sheet and a second member composed of aluminum or an aluminum alloy, wherein at least one portion constituting the aluminum alloy brazing sheet An Al—Si-based aluminum alloy brazing filler is placed in the gap between the first member and the second member containing Mg, and both members are brazed by heating in an inert gas without applying flux. A method for brazing an aluminum member, characterized in that the Mg content of the brazing filler metal filled in the gap after brazing is 75% or less of the Mg content of the brazing filler metal other than the gap.   A method of brazing a first member composed of an aluminum alloy brazing sheet and a second member composed of aluminum or an aluminum alloy, wherein the aluminum alloy brazing sheet comprises Mg: 0.2 to An Al-Mn-based aluminum alloy containing 1.0 mass% and comprising the balance Al and unavoidable impurities is used as a core material, and Si: 5 to 13 mass%, Mg: 0.05 mass% or less is contained on one or both sides of the core material. An Al—Si-based aluminum alloy brazing material composed of Al and inevitable impurities is clad, and Si: 5 to 13 mass%, Mg: 0 in the gap between the first member and the second member. An Al—Si based aluminum alloy brazing filler containing less than 2 mass% and comprising the balance Al and inevitable impurities is disposed. Then, both members are brazed by heating in an inert gas without applying flux, and the Mg content of the brazing filler material filled in the gap after brazing is 75% of the Mg content of the brazing filler other than the gap. A method for brazing an aluminum member, characterized by:   A method of brazing a first member composed of an aluminum alloy brazing sheet and a second member composed of aluminum or an aluminum alloy, wherein the aluminum alloy brazing sheet comprises an Al-Mn aluminum alloy. The core material is clad with a brazing material of an Al—Si based aluminum alloy containing Si: 5 to 13 mass%, Mg: 0.2 to 1.5 mass%, and the balance Al and inevitable impurities on one or both surfaces of the core material. The first member and the second member have a structure in which the surface of the brazing material is further clad with an aluminum alloy skin material containing 0.05% by mass or less of Mg and the balance Al and inevitable impurities. And Si: 5 to 13 mass%, Mg: 0.2 mass% or less, the balance Al and unavoidable Place an Al-Si aluminum alloy brazing filler made of impurities, heat it in an inert gas without applying flux, braze both members, and contain Mg in the brazing material filled in the gap after brazing The method for brazing an aluminum member, wherein the amount is 75% or less of the Mg content of the brazing material other than the gap.

Images