JP2013123749A - Fluxless brazing method for aluminum material and brazing sheet used for the same - Google Patents

Abstract

[Objective] This is a method of brazing aluminum material without using flux in an inert gas atmosphere furnace, brazing for automotive heat exchangers, etc. that have excellent bondability and require stable fillet forming ability An inexpensive brazing method that can be applied to brazing is provided.
[Structure] In a method of brazing an aluminum material without flux in an inert gas atmosphere, the aluminum material has Si: 6 to 13% on one side or both sides of a core material made of an Al-Mn aluminum alloy, Mg: 0.05 to 0.4%, Zr: 0.05 to 0.3%, Ce: 0.05 to 0.2%, Be: 0.01 to 0.04%, Ca: 0.005 A brazing sheet comprising one or more of ~ 0.03%, clad with an aluminum alloy brazing material consisting of the balance aluminum and inevitable impurities, and in the oxide film on the brazing material surface during brazing heating It is characterized by brazing while forming a spinel type compound to weaken the oxide film.
[Selection figure] None

Description

  The present invention relates to a brazing method for an aluminum material that does not use a flux, and a brazing sheet used in the brazing method.

  Brazing joining is widely used as a joining method for parts having many fine joints such as aluminum (including aluminum alloy) heat exchanger parts and machine parts. In order to braze and join an aluminum material, it is necessary to destroy the oxide film covering the surface of the aluminum material and bring the molten brazing material into contact with the base material or the molten brazing material.

  Even when a general Al—Si brazing material is heated to a melting temperature (577 ° C.) or higher in nitrogen gas, the surface of the brazing material is covered with a dense oxide film, and the base material or brazing material to be joined Also, the brazing filler metal cannot be wetted because it is covered with an oxide film. For example, even if the brazing filler metal surfaces are overlapped, firmly tightened and heated, the oxide film at the bonding interface is maintained without being destroyed, so it cannot be bonded at all, or a part is bonded in the form of dots. Just do.

  As a method of performing brazing joining by destroying an oxide film, there are roughly classified a flux brazing method using a flux and a vacuum brazing method of heating in a vacuum. The former is a method in which non-corrosive fluoride-based flux is used for joining by heating to about 600 ° C. in nitrogen gas, and most of recent automotive heat exchangers are brazed using fluoride-based flux. It is manufactured by the law.

  However, brazing using a fluoride-based flux has a problem in that it is difficult to apply brazed parts in food, medical, electronic equipment, and the like because flux residues remain after brazing. Further, when the refrigerant passage is very narrow, there is a problem that clogging occurs due to the residue of the flux, the refrigerant passage is blocked, and the heat exchange performance is deteriorated. The vacuum brazing method of heating in a vacuum furnace has a problem in productivity because the vacuum furnace equipment is expensive and the maintenance cost is high.

  As a method of brazing without using a flux in nitrogen gas without using a vacuum furnace, for example, adding a trace amount of elements such as Bi and Be into the brazing material, and adding a trace amount of Sb, Ba, Sr, etc. A method has been proposed in which brazing properties are improved and etching is performed with acid or alkali as a pretreatment before brazing and heating is performed in an inert gas such as nitrogen gas.

  However, there is a limit to the effect of improving the bondability by adding a small amount of Be or Mg. Even if surface bonding is possible, it is essential to damage the oxide film by etching with acid or alkali before brazing. Furthermore, very strict atmosphere management such as an oxygen concentration of 5 ppm or less and a dew point of −65 ° C. or less is also required. As a result, the fillet formation is not stable in actual production, and in particular, in a joint where the inner and outer surfaces of the heat exchanger communicate with each other, it is not possible to expect the effect of forming the fillet stably.

  Further, since the bonding property is not stable unless the oxide film is reduced by etching the brazing material before brazing heating, the application range is limited and the cost for the etching process becomes a problem. There has also been proposed a method in which a brazing material is subjected to Ni plating and bonded in an inert gas, but there is a problem that the cost for plating is high. It is also known that by adding Mg to the brazing material, it becomes possible to join to some extent even when heated in nitrogen gas, but there is a limit to the bondability because Mg does not actively evaporate. The fillet formation is also unstable and the gap filling ability is poor. Furthermore, although a method of adding Mg to the core material and the like instead of the brazing material has been proposed, there is no clear difference from the effect of adding Mg to the brazing material, and the effect of forming a fillet stably is not I can't show it.

Japanese Patent Laid-Open No. 50-19651 Special table 2003-500216 gazette

  As described above, any of the methods for brazing without using a flux in an inert gas atmosphere such as nitrogen gas has a problem in the fillet forming ability, so that the flux-less brazing performed in an inert gas atmosphere. Brazing is limited to brazing such as laminated heat exchangers that are all made of surface joints and given sufficient pressure, and have fins and headers, and a stable fillet forming ability Currently, it is hardly put to practical use for brazing of general automotive heat exchangers and the like that are required.

  The present invention has been made to solve the above-described conventional problems in the method of brazing an aluminum material without using a flux in an inert gas atmosphere, and its purpose is an inert gas atmosphere such as nitrogen gas. It is a method of brazing aluminum material without using flux in a furnace, and it can be applied to brazing of automotive heat exchangers that have excellent bondability and require stable fillet forming ability. It is to provide an inexpensive brazing method.

  A fluxless brazing method for an aluminum material according to claim 1 for achieving the above object is a method of brazing an aluminum material without flux in an inert gas atmosphere, wherein the aluminum material is Al-Mn. One side or both sides of the core material made of an aluminum alloy contains Si: 6 to 13% (mass%, the same shall apply hereinafter), Mg: 0.05 to 0.4%, and Zr: 0.05 to 0.3% , Ce: 0.05 to 0.2%, Be: 0.01 to 0.04%, Ca: 0.005 to 0.03%, including one or more, the balance aluminum and unavoidable A brazing sheet clad with an aluminum alloy brazing material made of impurities. During brazing heating, a spinel-type compound is formed in the oxide film on the surface of the brazing material to make the oxide film brittle And wherein the Kesuru.

  The fluxless brazing method for an aluminum material according to claim 2 is the aluminum alloy brazing material according to claim 1, wherein the core material is made of an Al-Mn aluminum alloy containing at least Mg: 0.2 to 1.0%. However, Si: 6-13%, Zr: 0.05-0.3%, Ce: 0.05-0.2%, Be: 0.01-0.04%, Ca: 0.005 It is characterized by comprising an aluminum alloy brazing material containing one or more of ˜0.03%, the balance being aluminum and unavoidable impurities, and limiting Mg to 0.2% or less.

  A fluxless brazing method for an aluminum material according to claim 3 is characterized in that, in claim 1, the brazing sheet contains Si: 6 to 13% on one or both sides of a core material made of an Al-Mn-based aluminum alloy. : 0.05 to 0.3%, Ce: 0.05 to 0.2%, Be: 0.01 to 0.04%, Ca: one or two of 0.005 to 0.03% An aluminum alloy brazing material including the above, the balance aluminum and unavoidable impurities, and limiting Mg to 0.2% or less, and sandwiching an intermediate material made of an aluminum alloy containing at least Mg: 0.2 to 1.0% It is characterized by being clad with.

  A fluxless brazing method of an aluminum material according to claim 4 is the method according to claim 1, wherein the brazing sheet is made of an Al-Mn aluminum alloy containing at least Mg: 0.2 to 1.0%. Further, Si: 6 to 13%, Zr: 0.05 to 0.3%, Ce: 0.05 to 0.2%, Be: 0.01 to 0.04%, Ca: 0.005 An aluminum alloy brazing material containing one or two or more of 0.03%, the balance being aluminum and inevitable impurities, and limiting Mg to 0.2% or less, and Mg to 0.2% or less It is characterized by being clad with an intermediate material made of a restricted aluminum alloy and having a thickness of 0.07 mm or less.

  A fluxless brazing method for an aluminum material according to claim 5 is the Mg-O-based compound present in an oxide film on the surface of the brazing material when brazed to 600 ° C in any one of claims 1 to 4. 70% or more is a spinel type compound.

  The brazing sheet according to claim 6 is used in the fluxless brazing method for an aluminum material according to any one of claims 1 to 4, and the core material and the aluminum alloy brazing material according to any one of claims 1 to 4, Or it consists of a combination of a core material, an aluminum alloy brazing material and an intermediate material.

  It is a method of brazing aluminum material without using flux in an inert gas atmosphere furnace such as nitrogen gas, and it has excellent bondability and stable heat fillet formation capability such as automotive heat exchanger An inexpensive brazing method that can be applied to brazing is provided.

It is a figure which shows the gap filling test piece used in an Example.

Preferred embodiments of the configuration of the brazing sheet used in the present invention are as follows.
(First embodiment: a brazing sheet according to claim 1)
Core material: Al-Mn alloy (hereinafter referred to as 1C). A preferable content of Mn is in the range of 1.0 to 1.5%, 0.3% or less of Cu, 0.4% or less of Cr, Zn, Zr, 0.2% or less of Ti, 0.05% or less. % B or less may be included.
Brazing material: Si: 6 to 13%, Mg: 0.05 to 0.4%, Zr: 0.05 to 0.3%, Ce: 0.05 to 0.2%, Be: 0. An aluminum alloy brazing material (hereinafter referred to as 1B) comprising one or more of 01 to 0.04%, Ca: 0.005 to 0.03%, and the balance aluminum and inevitable impurities.

(Second embodiment: the brazing sheet according to claim 2)
Core: Al—Mn alloy containing 0.2 to 1.0% of Mg (hereinafter referred to as 2C). A preferable content of Mn is in the range of 1.0 to 1.5%, 0.3% or less of Cu, 0.4% or less of Cr, Zn, Zr, 0.2% or less of Ti, 0.05% or less. % B or less may be included.
Brazing material: Si: 6 to 13%, Zr: 0.05 to 0.3%, Ce: 0.05 to 0.2%, Be: 0.01 to 0.04%, Ca: 0. An aluminum alloy brazing material (hereinafter referred to as 2B) containing one or more of 005 to 0.03%, consisting of the balance aluminum and unavoidable impurities, and limiting Mg to 0.2% or less.

(Third embodiment: the brazing sheet according to claim 3)
Core material: Al-Mn alloy (1C).
Intermediate material: Mg: An intermediate material (1 L) made of an aluminum alloy containing 0.2 to 1.0%.
Brazing material: Aluminum alloy brazing material (2B).

(Fourth embodiment: a brazing sheet according to claim 4)
Core: Al—Mn alloy containing 0.2 to 1.3% of Mg (hereinafter 3C). A preferable content of Mn is in the range of 1.0 to 1.5%, 0.3% or less of Cu, 0.4% or less of Cr, Zn, Zr, 0.2% or less of Ti, 0.05% or less. % B or less may be included.
Intermediate material: Intermediate material (2L) (thickness 0.07 mm or less) made of an aluminum alloy with Mg limited to 0.2% or less.
Brazing material: Aluminum alloy brazing material (2B).

  The significance of the components in the aluminum alloy brazing material and the reasons for its limitation will be described. Si is an essential component for imparting fluidity to the brazing material, and the preferred content is in the range of 6 to 13%. If it is less than 6%, the fluidity is lowered and the action as a brazing material is insufficient, and if it exceeds 13%, it is difficult to produce a sound material.

  When a small amount of Be or Mg is added to the brazing material, the oxide film is divided in some places and can be joined in a planar shape. Be and Mg are elements that are easier to oxidize than Al. When these elements form oxides on the surface of the brazing material, the uniformity of the oxide film of Al covering the brazing material surface disappears and occurs there. The molten solder comes into contact with and joins through the cracks in the oxidized film. The same applies to the case where the mating material to be joined is not a brazing material but an aluminum base material, and a brazing material to which Be or Mg is added is easily wetted with respect to the base material.

  If the amount of Be added to the brazing material exceeds 0.04%, the oxide of Be formed at the time of manufacturing the material becomes a barrier and the brazing joint property is deteriorated. Mg also forms an oxide on the surface of the brazing material during the material production, as with Be. However, when the amount of Mg added is up to 0.4%, the fillet forming ability is improved, and the amount of Mg added is further increased. However, the fillet-forming ability is not improved, and the fillet-forming ability gradually decreases when the addition amount exceeds 1.0%. The preferable addition ranges of Mg and Be to the brazing filler metal are Mg 0.05 to 0.4% and Be 0.01 to 0.04%, respectively.

Zr, Ce, and Ca are also elements that improve fillet forming ability by adding a small amount.
These elements, like Mg and Be described above, are both elements whose oxide free energy of formation is equal to or less than that of Al. When an element whose free energy of oxide formation is equal to or less than that of Al is added to the brazing material, oxides of Mg, Be, Zr, Ce, and Ca are formed in the aluminum oxide film formed on the surface of the aluminum alloy material. This promotes crushing of the aluminum oxide film during brazing heating. Fillet forming ability can be improved by containing Zr in the range of 0.05 to 0.3%, Ce in the range of 0.05 to 0.2%, and Ca in the range of 0.005 to 0.03%.

The inclusion of Mg alone does not improve the fillet forming ability to a practical level, but the inventors have found that Mg can exhibit an effect different from Be, Zr, Ce, and Ca. . According to the analysis results, it is recognized that a large amount of spinel-type Al ₂ MgO ₄ is formed in the oxide film on the material surface when the amount of Mg added to the brazing material is in the range of 0.05 to 0.4%. The Al ₂ MgO ₄ is considered to impair the homogeneity of the oxide film.

The formation of Al ₂ MgO ₄ increases even if the Mg content exceeds 0.4%, and the uniformity of the oxide film is lost, but if the Mg content exceeds 0.4%, the oxide film The formation of MgO becomes conspicuous in the outermost layer portion. MgO is presumed to inhibit the melting of the brazing filler metal. When the Mg content exceeds 0.4%, MgO formation increases with the content, and when the content exceeds 1.0%, fillet formation occurs. Cause a decrease in performance.

  Thus, it was confirmed that Mg forms two types of oxides having different forms depending on the content in the oxide film and on the surface layer of the oxide film, and that they have an effect on the fillet forming ability. That is, when the Mg content is in the range of 0.4 to 1.0%, the fillet forming ability is almost constant due to the formation of oxides that have two conflicting effects. In order to improve to a possible level, it is indispensable that the molten wax pushes up the oxide film during the fillet formation as well as creating a starting point where the molten wax wets the counterpart material. For this purpose, it is necessary to sufficiently crush the oxide film covering the surface of the brazing material when the brazing material is melted.

In order to realize this, in the present invention, the effects of the above additive elements are combined as follows.
(1) By adding a trace amount of an element having an oxide generation free energy equal to or less than that of Al to the brazing material, an oxide that is a starting point for crushing the oxide film is formed in the oxide film (wedge effect).
(2) In the range in which the formation of MgO on the oxide film surface is suppressed, a spinel type compound (Al ₂ MgO ₄ ) is formed in the oxide film during material production and during brazing heating (substitution effect) ).

The oxide formation free energy at 600 ° C. is −952 kJ / mol for Al (Al ₂ O ₃ ), whereas −945 kJ / mol for Zr (ZrO ₂ ) and − (Ce ₂ O ₃ ) is − 1033 kJ / mol, Be (BeO) is -1041 kJ / mol, and Ca (CaO) is -1106 kJ / mol, which is equal to or less than Al. Even if any element is contained, it effectively acts as a wedge effect for crushing the oxide film, but the appropriate content range tends to decrease as the oxide free energy for formation decreases.

Although the free energy of oxide formation of Mg (MgO) at 600 ° C. is also as low as −1062 kJ / mol, a spinel-type oxide (Al ₂ MgO ₄ ) is preferentially formed in the Al oxide film, so Zr, Behaves differently from Ce, Be, and Ca. Further, when the amount of Mg increases, MgO is formed on the surface layer portion of the oxide film to inhibit the wetting of the wax. Therefore, it is necessary to suppress the formation of MgO while forming Al ₂ MgO ₄ . In particular, regarding the generation of MgO, it is important to suppress the generation of MgO in order to lose the effect of adding Zr, Ce, Be, and Ca (wedge effect).

Since the formation ratio of Al ₂ MgO ₄ and MgO is determined by the amount of Mg in the vicinity of the oxide film, Mg is contained in either the brazing material, the intermediate material, or the core material. From the results of diffusion simulation and experimental confirmation, the Mg content is 0.05 to 0.4% for the brazing material, 0.2 to 1.0% for the core material or intermediate material, as shown in the above embodiment. The core material combined with the intermediate material having a thickness of 0.07 mm or less and the Mg content limited to less than 0.2% is in the range of 0.2 to 1.3%.

  The intermediate material is interposed between the core material and the brazing material for the purpose of giving a sacrificial anode effect, and as described above, the intermediate material made of an aluminum alloy containing Mg: 0.2 to 1.0% ( 1L), or an intermediate material (2L) (thickness of 0.07 mm or less) made of an aluminum alloy with Mg limited to less than 0.2% is applied.

  In order to give a sacrificial anode effect, the intermediate material preferably contains 0.8 to 1.8% of Zn, and in addition, 0.3 to 0.8% of Mn can also be contained.

  In the brazing method of the present invention, when brazing is performed at a temperature of 600 ° C., it is preferable that 70% or more of the Al—Mg compound existing in the oxide film on the surface of the brazing material is a spinel type compound. In order to make 70% or more of the Mg-O-based compound present in the oxide film on the surface of the brazing material into a spinel type compound, as described above, a predetermined amount of Zr, Ce, Be, Ca is used alone in the brazing material. Alternatively, the brazing sheet including the combination shown in the first to fourth embodiments, in which Mg is contained in any of the brazing material, the intermediate material, and the core material, and the Mg content is in an appropriate range, while being combined and contained. It is important to use and braze by controlling the amount of Mg acting on the surface.

  Hereinafter, examples of the present invention will be described and the effects thereof will be demonstrated. These examples show one embodiment of the present invention, and the present invention is not limited thereto.

Example 1
Brazing sheets 1 to 18 having a thickness of 0.4 mm with one side of the core material clad with brazing material, and brazing sheets 19 to 24 having a thickness of 0.4 mm with one side of the core material clad with the brazing material via an intermediate material are always used. Prepared according to the method. Table 1 shows the alloy compositions of the core material, the brazing material, and the intermediate material. The thickness of each brazing material was 0.04 mm, and the thickness of the intermediate layer was 0.05 mm.

  The brazing sheets 1 to 15 correspond to the first embodiment among the preferred embodiments of the configuration of the brazing sheet, the brazing sheets 16 to 18 correspond to the second embodiment, and the brazing sheets 19 to 21 are the first. 3 corresponds to the third embodiment, and the brazing sheets 22 to 24 correspond to the fourth embodiment. About the obtained brazing sheets 1-24, the gap filling test was done with the following method.

Gap filling test: As shown in FIG. 1, 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 of nitrogen gas was fed into each chamber of the nitrogen gas furnace, and the temperature was raised from 450 ° C. to 595 ° C. in about 12 minutes. The oxygen concentration in the brazing chamber at the end of heating was 10 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 test piece after cooling to evaluate the fillet forming ability, and the gap filling length of 20 mm or more was regarded as acceptable as described later. The evaluation results are shown in Table 1. As can be seen from Table 1, all the brazing sheets 1 to 24 according to the present invention were formed with fillets having a gap filling length of 21 to 34 mm in the gap filling test, and sufficiently exhibited a fillet forming ability at a practical level.

For brazing sheets 1 to 24, the surface of the brazing material after brazing and joining was observed with a transmission electron microscope, and the Mg—O compound in the oxide film was examined by electron diffraction. The ratio of the spinel type compound (Al ₂ MgO ₄ ) in the compound exceeded 70%.

REFERENCE EXAMPLE As a reference, as shown in Table 2, 10 g / m ² fluoride flux is applied to a brazing sheet 47 of a general component in which an Al-10% Si alloy brazing material is clad on an Al-1.2% Mn alloy core. When a gap filling test was conducted, a fillet with a gap filling length of 38 mm was formed. Further, a brazing sheet 48 in which an Al-10% Si-1.6% Mg alloy brazing material is clad with an Al-1.2% Mn alloy core is heated and bonded in a vacuum furnace depressurized to 2.0 × 10 ⁻³ Pa. When a gap filling test was performed, a fillet having a gap filling length of 20 mm was formed. A test piece (brazing sheet) obtained by this vacuum brazing method that gave a gap filling length of 20 mm or more was judged to be a practical level.

  Further, as a reference, brazing sheets 49 and 50 in which an Al-10% Si-0.02% Bi-0.01% Be alloy brazing material is clad with an Al-1.2% Mn alloy core material are produced. For the brazing sheet 50, both the horizontal material and the vertical material were immersed in a mixed solution of 2% nitric acid and 1% hydrofluoric acid for 90 seconds and etched. As a result of assembling and performing a gap filling test, the gap filling length of the brazing sheet 49 with only the degreasing treatment was as small as 6 mm, but the gap filling length of the etched brazing sheet 50 was 26 mm.

For the brazing sheet shown as the reference example, the surface of the brazing material after brazing and joining was observed with a transmission electron microscope, and the Mg—O-based compound in the oxide film was examined by electron diffraction. In the brazing sheet having a thickness of 20 mm or more, the ratio of the spinel type compound (Al ₂ MgO ₄ ) in the Mg—O-based compound formed on the surface was 70% or more.

Comparative Example 1
Brazing sheets 25 to 43 having a thickness of 0.4 mm each having a brazing material clad on one side of the core material, and brazing sheets 44 to 46 having a thickness of 0.4 mm having a brazing material clad on one side of the core material via an intermediate material are always used. Prepared according to the method. Table 3 shows the alloy compositions of the core material, the brazing material, and the intermediate material. The thickness of each brazing material was 0.04 mm, and the thickness of the intermediate layer was 0.05 mm.

  About the obtained brazing sheets 25-46, the gap filling test was done by the method similar to an Example, the gap filling length was measured, and the fillet formation ability was evaluated. The evaluation results are shown in Table 3.

  In Table 3, brazing sheets 1 to 35 are brazing sheets corresponding to those deviating from the configuration of the first embodiment. As shown in Table 3, since the brazing sheets 25 and 28 have Zr and Ca in the brazing material exceeding the upper limit values, cracks occur during the production of the brazing sheet (during rolling), and a test material can be obtained. There wasn't. In the brazing sheets 26 and 27, Ce and Be in the brazing material exceeded the upper limit value, and therefore the gap filling length was small and sufficient fillet forming ability was not obtained.

  Since the brazing sheet 29 has a small amount of Mg in the brazing material, and the brazing sheet 30 has a large amount of Mg in the brazing material, the gap filling length is small and sufficient fillet forming ability cannot be obtained. Since the brazing sheet 31 contained neither Mg nor Zr, Ce, Be, or Ca in the brazing material, and the brazing sheets 32 to 35 each contained only Mg, the gap filling length was all. Small and sufficient fillet forming ability could not be obtained.

  The brazing sheets 36 to 43 are brazing sheets corresponding to those that deviate from the configuration of the second embodiment. Since the brazing sheet 36 did not contain Zr, Ce, Be, and Ca in the brazing material, and the brazing sheets 37 to 41 were those in which the core material did not contain Mg, the gap filling length was small enough. Fillet forming ability was not obtained.

  Since the brazing sheet 42 has a small amount of Mg in the core material and the brazing sheet 43 has a large amount of Mg in the core material, the gap filling length is small and sufficient fillet forming ability cannot be obtained.

  The brazing sheet 44 is a brazing sheet corresponding to the one out of the configuration of the third embodiment, and the brazing sheets 45 to 46 are brazing sheets corresponding to the one out of the configuration of the fourth embodiment. . Since the brazing sheet 44 has a small amount of Mg in the intermediate material, the gap filling length is small and sufficient fillet forming ability was not obtained. Since the brazing sheet 45 has a large amount of Mg in the core material, and the brazing sheet 46 has a small amount of Mg in the core material, the gap filling length was small and sufficient fillet forming ability was not obtained.

Claims (6)

A method of brazing an aluminum material without flux in an inert gas atmosphere, wherein the aluminum material has Si: 6 to 13% (mass%, on one side or both sides of a core material made of an Al-Mn based aluminum alloy. The same shall apply hereinafter), Mg: 0.05 to 0.4%, Zr: 0.05 to 0.3%, Ce: 0.05 to 0.2%, Be: 0.01 to 0.04% , Ca: a brazing sheet containing one or more of 0.005 to 0.03%, clad with an aluminum alloy brazing material consisting of the balance aluminum and inevitable impurities, and brazing during brazing heating A fluxless brazing method for an aluminum material, characterized by forming a spinel-type compound in a surface oxide film and brazing while weakening the oxide film. The core material is made of an Al—Mn-based aluminum alloy containing at least Mg: 0.2 to 1.0%, the aluminum alloy brazing material contains Si: 6 to 13%, and Zr: 0.05 to 0 3%, Ce: 0.05 to 0.2%, Be: 0.01 to 0.04%, Ca: 0.005 to 0.03%, including one or more, and the balance aluminum 2. The fluxless brazing method for an aluminum material according to claim 1, wherein the fluxless brazing method is made of an aluminum alloy brazing material made of unavoidable impurities and Mg limited to 0.2% or less. The brazing sheet contains Si: 6 to 13% on one side or both sides of a core material made of an Al—Mn-based aluminum alloy, Zr: 0.05 to 0.3%, and Ce: 0.05 to 0.2. %, Be: 0.01 to 0.04%, Ca: 0.005 to 0.03%, or one or more of the remaining aluminum and the inevitable impurities, Mg is 0.2% The flux of aluminum material according to claim 1, wherein the aluminum alloy brazing material limited to the following is clad with an intermediate material made of an aluminum alloy containing at least Mg: 0.2 to 1.0% interposed therebetween. Less brazing method. The brazing sheet contains Si: 6-13% on one or both sides of a core material made of an Al—Mn aluminum alloy containing at least Mg: 0.2-1.0%, and Zr: 0.05-0. 3%, Ce: 0.05 to 0.2%, Be: 0.01 to 0.04%, Ca: 0.005 to 0.03%, including one or more, and the balance aluminum And an aluminum alloy brazing material made of unavoidable impurities, with Mg limited to 0.2% or less, and an intermediate material made of aluminum alloy with Mg limited to 0.2% or less and having a thickness of 0.07 mm or less The fluxless brazing method for an aluminum material according to claim 1, wherein: When brazing and heating to a temperature of 600 ° C, 70% or more of the Mg-O-based compound existing in the oxide film on the surface of the brazing material is a spinel type compound. The fluxless brazing method of aluminum material as described in 1. The core material and the aluminum alloy brazing material according to any one of claims 1 to 4, or the core material and the aluminum alloy brazing material, which are used in the fluxless brazing method for an aluminum material according to any one of claims 1 to 4. A brazing sheet comprising a combination of intermediate materials.

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