JP2010247209A - Fluxless brazing method for aluminum material and aluminum cladding material for fluxless brazing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable fluxless brazing under atmospheric pressure without necessity of flux and vacuum equipment. <P>SOLUTION: An aluminum cladding material includes Al-Si-based brazing material containing 0.1-5.0 mass% Mg and 3-13 mass% Si on the top surface thereof. A tight joining part abutting with a work to be brazed is joined by the Al-Si based brazing material at a heating temperature of 559-620°C in the non-oxidizing atmosphere without vacuuming. Thus, the fluxless brazing under atmospheric pressure without requiring the flux and the vacuum equipment is made possible so that Mg addition to a component member to be brazed other than the brazing material cannot be an impediment factor for the brazing. Further, heating in the atmosphere without vacuuming can hardly cause contamination on the inside wall of furnace etc. due to evaporation of Mg and Zn. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an aluminum clad material that can be brazed without using a flux in a non-oxidizing atmosphere, and a brazing method thereof.

Heat exchangers for automobiles, such as radiators and condensers, intercoolers, etc., and other heat exchangers and radiators manufactured from aluminum alloys, now use non-corrosive fluoride fluxes. The mainstream is a method of brazing or brazing under vacuum by adding about 0.5 to 1.5% by mass of Mg to the brazing material.
In the case of using the above-mentioned flux, most of the members to be brazed are processed by press molding or the like, and then put into a desired assembled state, and a turbid liquid in which flux powder is dissolved in a solvent is applied to the assembled body and dried, and a high-purity nitrogen gas atmosphere Heat brazing in a non-oxidizing atmosphere such as In this case, there is a problem that the use of the flux itself, or the cost of installation and management of the coating process is required. In addition, it is known that a part of the flux evaporates during the brazing heating process and adheres to and accumulates on the inner wall of the furnace, and periodic furnace maintenance for removing the deposits also occurs as a necessary cost. . In recent years, with the promotion of weight reduction of automobiles, the heat exchangers for automobiles are also required to increase the thickness and strength of materials, and it is common to add Mg to aluminum alloys to increase the strength of aluminum materials. However, when brazing using a flux, Mg and the flux react to produce high melting point MgF ₂ , which may cause brazing inhibition or consume Mg in the material. However, there is a problem that the added Mg is not very useful for increasing the strength. That is, in flux brazing, there are limitations on the sites and amounts of Mg added in the product, and the current situation is that they cannot be actively used as a method for increasing the strength of materials.

  On the other hand, in vacuum brazing, Mg added to the brazing material evaporates from the material during the brazing temperature rising process, and at that time, the oxide film on the surface of the aluminum material, which is a brazing inhibition factor, is destroyed. The atmosphere inside the furnace can be brazed by the getter action combined with oxygen and oxygen. Although this method does not require the flux process control, there are problems that the vacuum furnace is an expensive facility and that the corresponding cost is required for the airtightness management of the furnace. In addition, in heat exchangers for automobiles, Zn is added for the purpose of ensuring the corrosion resistance of the product. However, there is a demerit that Zn is evaporated under vacuum heating, and sufficient Zn cannot be left in the product material. is there. Furthermore, since evaporated Mg and Zn accumulate on the inner wall of the furnace, periodic cleaning of the furnace is also required.

  On the other hand, fluxless brazing under atmospheric pressure has recently been proposed to solve the above problems. For example, Patent Document 1 proposes flux-less brazing under a non-oxidizing atmosphere and atmospheric pressure by placing an Mg-containing material on a brazed member or other part and covering the brazed material. is doing. However, in this technology, it is essential to cover, and it is necessary to prepare covers for each product size, it is necessary to prepare the number of pieces used in mass production, and further maintenance of the cover is required. There is a problem that it takes time and cost in mass production. Moreover, there is also a problem that the temperature rise rate of the brazed object is lowered by covering, and the productivity is lowered.

  To solve the above problem, Patent Document 2 proposes a mechanism in which a brazing member (cover) heated in the brazing furnace in advance is used to cover the brazed member in the furnace, thereby improving the decrease in the heating rate. Yes. However, in this method, it is necessary to provide a mechanism for controlling the operation of the windbreaker in the furnace, and there is a problem that it takes cost and labor to introduce and maintain equipment.

  On the other hand, as a fluxless brazing that does not require a cover, in Patent Document 3, Mg is added to a brazing material of a clad material, and the inside of the heat exchanger tube formed by the clad material is set to atmospheric pressure in an inert atmosphere. A fluxless brazing method has been proposed below.

  Similarly, as a method that does not require a cover, Patent Document 4 proposes a method in which a brazing material surface is clad with an antioxidant layer and the clad material is laminated to enable brazing in an air atmosphere. is there.

  In Patent Document 5, if the surface of the core material is clad with a brazing material made of an Al—Si—Mg alloy, and the material surface is acid-washed before brazing to reduce the thickness of the oxide film to 20 mm or less, There is a proposal that enables fluxless brazing in an oxidizing atmosphere.

JP-A-9-85433 JP 2006-175500 A Japanese Patent No. 4037477 Japanese Patent No. 3701847 Japanese Patent Laid-Open No. 10-180489

However, Patent Documents 3 to 5 that enable brazing under atmospheric pressure without requiring a cover also have the following problems.
In the method proposed in Patent Document 3, a flux is used to join the outer surface of the tube and the fin, and there is a problem that the disadvantages of using the flux are not completely eliminated.
Further, in the technique proposed in Patent Document 4, it is necessary to prepare a clad material in which an anti-oxidation layer is provided on the surface of the brazing material with respect to the material used for the conventional vacuum brazing or nocolok brazing, and the material cost is low. There is a problem that it becomes high, and there is a problem of versatility that the core is limited to a laminated structure.
Furthermore, the method disclosed in Patent Document 5 has a problem that the process management of the acid cleaning becomes complicated and the cost for the acid cleaning process increases.

  In view of such problems, the present invention does not generate new operation costs such as introduction and operation costs such as flux application process and vacuum equipment, sub-material costs such as a cover used at the time of brazing, and material acid cleaning, and It was developed for the purpose of finding a general-purpose fluxless brazing method under atmospheric pressure that does not depend on the shape of a heat exchanger or the like.

  In order to achieve the above object, the present inventors have conducted intensive research, and as a result, by keeping the amount of Mg added to the brazing material of the clad material within an appropriate range, the closely joined joint joint can be removed without depressurization. It has been found that a good brazing state can be obtained without using a cover for preventing Mg vapor from escaping in an oxidizing atmosphere. At this time, it is not necessary to dare to remove the initial oxide film on the surface of the material before brazing, and a commonly produced aluminum material can be used.

  That is, in the fluxless brazing method of the aluminum material of the present invention, the first present invention is an Al—Si system containing, by mass%, 0.1 to 5.0% Mg and 3 to 13% Si. A brazing method using an aluminum clad material in which the brazing material is located on the outermost surface, and a brazing target member by the Al-Si brazing material at a heating temperature of 559 to 620 ° C. in a non-oxidizing atmosphere without decompression. It is characterized in that the contact close contact portion is joined.

  The fluxless brazing method for an aluminum material according to the second aspect of the present invention is the method according to the first aspect, wherein the Si particles contained in the Al—Si brazing material have an equivalent circle diameter of 0.8 μm or more. Among them, the number of those having a diameter of 1.75 μm or more is 25% or more.

  In the fluxless brazing method for an aluminum material according to the third aspect of the present invention, in the first or second aspect of the present invention, the surface roughness of at least the contact adhesion portion surface of the aluminum clad material and the member to be brazed is Ra is 0.3 μm or less.

  A fluxless brazing method for an aluminum material according to a fourth aspect of the present invention is the method according to any one of the first to third aspects, wherein the Al-Si brazing material is 0.01% to 1.0% by mass. Bi is contained.

  In the fluxless brazing method of the aluminum material of the fifth invention, the core material in which the Al-Si brazing material is clad in any one of the first to fourth inventions is in mass%, It contains Si: 0.1 to 1.2%, Mg: 0.01 to 2.0%, and has a composition composed of the balance Al and inevitable impurities.

  In the fluxless brazing method of the aluminum material of the sixth aspect of the present invention, in any one of the first to fourth aspects of the present invention, the core material on which the Al-Si brazing material is clad is in mass%, Mn: 0.2-2.5%, Cu: 0.05-1.0%, Si: 0.1-1.2%, Fe: 0.1-1.0%, the balance Al And a composition comprising inevitable impurities.

  In the fluxless brazing method of the aluminum material of the seventh aspect of the present invention, in any one of the first to fourth aspects of the present invention, the core material on which the Al—Si based brazing material is clad is in mass%, Si: 0.1 to 1.2%, Mg: 0.01 to 2.0%, Mn: 0.2 to 2.5%, Cu: 0.05 to 1.0%, Fe: It is characterized by containing one or more of 0.1 to 1.0% and having a composition composed of the balance Al and inevitable impurities.

  The fluxless brazing method of the aluminum material according to the eighth aspect of the present invention, in any one of the first to fourth aspects of the present invention, the core material clad with the Al-Si brazing material is in mass%, Si: 0.1 to 1.2%, Mg: 0.01 to 2.0%, Mn: 0.2 to 2.5%, Cu: 0.05 to 1.0%, Fe: It contains one or more of 0.1 to 1.0%, Zr: 0.01 to 0.3%, Ti: 0.01 to 0.3%, Cr: 0.01 to 0 0.5%, Bi: 0.01 to 1.0% of one or more of them, and having a composition composed of the balance Al and inevitable impurities.

  An aluminum clad material for fluxless brazing according to a ninth aspect of the present invention is an Al-Si based brazing material obtained by cladding the Al-Si based brazing material according to any one of the first to fourth aspects of the present invention on a core material. The material is located on the outermost surface and is subjected to fluxless brazing in a non-oxidizing atmosphere without decompression.

  The aluminum clad material for fluxless brazing according to a tenth aspect of the present invention is characterized in that, in the ninth aspect, the core material has the composition described in any one of the fifth to eighth aspects. To do.

  Below, the reason for limitation of the component etc. which are prescribed | regulated by this invention is demonstrated below. In addition, each component amount is shown by mass%.

1. Brazing material In the aluminum clad material used in the present invention, a brazing material based on an Al-Si alloy and added with Mg is used.

  Although content of Si is not specifically limited, About 3 to 13% generally used as a brazing material is suitable, and 6 to 12% is more suitable. If it is less than 6%, the amount of liquid phase at the time of brazing tends to be insufficient, and if it exceeds 12%, it becomes a hypereutectic Si region of an Al—Si based alloy, and the workability at the time of producing an aluminum plate tends to deteriorate. Because.

  The content of Mg is preferably 0.1 to 5.0%. If it is less than 0.1%, the effect of the present invention, which is the effect of the present invention, cannot be obtained by the effect of preventing reoxidation of the joint surface at the time of brazing. Saturates and causes difficulty in workability of the aluminum material. In the present invention, brazing properties can be secured only by the oxide film destruction activity in the above Mg component range, but further, the Mg content is optimized and the effect of lowering the solidus temperature of the Al—Si—Mg brazing material is utilized. If this is the case, excellent brazing properties can be exhibited. The optimum Mg content in this case varies depending on the Si content. For example, when the Si content is 6 to 12%, the Mg content is preferably 0.75 to 1.5%. If it is this range, the melting | fusing point fall of a solder | brazing | wax will fully be acquired, and it becomes possible to obtain a more favorable brazing property by the synergistic effect with the getter action by Mg. Specifically, brazing can be performed at the lowest solidus temperature of 559 ° C. or higher with an Al—Si—Mg alloy.

The brazing material can contain Zn as appropriate for the purpose of improving the corrosion resistance of the product. This component can be contained at a content of 0.1 to 5.0%, for example. Further, in order to obtain a bond in the present invention, Bi is not essential, but by incorporating Bi, the wettability of the brazing material can be further improved.
The Bi content is preferably 0.01 to 1.0%. If it is less than 0.01%, the effect is not sufficient, and if it exceeds 1.0%, the effect is saturated and the material cost is increased.

In carrying out the present invention, it is preferable that relatively coarse Si particles exist on the surface of the brazing material. Usually, a dense oxide film such as Al ₂ O ₃ is present on the surface of the aluminum material, and this further grows to become a thick film in the brazing heat treatment process. The general view is that the greater the thickness of the oxide film, the stronger the tendency to inhibit the destruction of the oxide film. In the present invention, since coarse Si particles are present on the surface of the brazing material, a dense oxide film of aluminum does not grow on the surface of the coarse Si particles, and this site works as an oxide film defect on the surface of the aluminum material. That is, even if the oxide film on the surface of the aluminum material becomes thick during the brazing heat treatment, the brazing material oozes out from the Si particle portion, and the oxide film destruction action proceeds from this site. Conceivable. The term “Si particles” as used herein includes Si particles due to the composition of Si as a single component, and also includes, for example, Fe—Si compounds and Al—Fe—Si intermetallic compounds mainly composed of Fe—Si. Shall be. In the description of the present invention, these are referred to as Si particles for convenience. Specifically, when the Si particles on the surface of the brazing material are regarded as equivalent circle diameters and the number of Si particles of 0.8 μm or more is counted and 25% or more of those having 1.75 μm or more are present, this effect is sufficiently obtained. It is done. Although the density of the Si particles is not mentioned in the present invention, the number of Si particles of 0.8 μm or more in the 10000 μm ² field of view is several tens depending on the alloy composition used in the present invention, the manufacturing condition range, and the finished plate thickness of the material. In the present invention, if the number of particles having a diameter of 1.75 μm or more is 25% or more, the effect is obtained. After confirming that it was obtained, the above regulations were made desirable.

2. Core material The core material composition of the aluminum clad material used in the present invention is not particularly limited in obtaining a bond, but by realizing fluxless brazing, Mg addition aiming at high strength is actively added. Yes.
As a core component, what contains Si: 0.1-1.2% and Mg: 0.01-2.0% by mass ratio, and the remainder consists of Al and an unavoidable impurity are shown.
Moreover, by mass ratio, Mn: 0.2-2.5%, Cu: 0.05-1.0%, Si: 0.1-1.2%, Fe: 0.1-1.0%, Containing the balance Al and inevitable impurities.
As the core material component, one or more of Mn: 0.2 to 2.5%, Cu: 0.05 to 1.0%, and Fe: 0.1 to 1.0% are contained. If desired, Zr: 0.01 to 0.3%, Ti: 0.01 to 0.3%, Cr: 0.01 to 0.5%, Bi: 0.01 to 1.0% One or two or more types are contained, and the balance is composed of Al and inevitable impurities. The action of each element and the reasons for limitation are as follows.

Si: 0.1-1.2%
In addition to improving the material strength by dissolving Si in a matrix with a simple substance of Si, in the present invention, the material strength is improved by precipitation of Mg ₂ Si obtained by a synergistic effect with the positive addition of Mg. This hardening by Mg ₂ Si precipitation contributes to a dramatic improvement in material strength by aging precipitation after brazing heat treatment. In an alloy design based on the conventional A3003 alloy or the like, it is dispersed as an Al—Mn—Si compound to improve the material strength. If the amount is less than the lower limit, the effect is insufficient. If the upper limit is exceeded, the melting point decreases and the core material melts, so the above range is desirable. In addition, the more preferable range of Si content is 0.3 to 1.0%. When positive inclusion of Si is not required due to inclusion of Mn or the like, it is allowed to contain less than 0.1% of Si as an impurity.

Mg: 0.01-2.0%
When Mg is added simultaneously with Si, it precipitates as a fine intermetallic compound Mg ₂ Si after brazing and has the effect of significantly improving strength by age hardening. Moreover, it reacts with Si diffused from the brazing material during the brazing heat and has the same strength effect. Further, a part of it diffuses into the brazing material and contributes to the action of suppressing the oxide film destruction and oxide film growth on the surface of the brazing material. Below the lower limit, the effect is insufficient, and when the upper limit is exceeded, the melting point decreases and the core material melts. For this reason, the above range is desirable for the Mg content.

Mn: 0.2 to 2.5%
Mn crystallizes or precipitates as an intermetallic compound, and improves the strength after brazing. In addition, the corrosion resistance is improved by making the potential of the core material noble. If it is less than the lower limit, the effect is insufficient, and if it exceeds the upper limit, workability such as rolling deteriorates. In addition, further effects cannot be obtained. For these reasons, the Mn content is preferably within the above range. In addition, the more preferable range of Mn content is 0.5 to 1.5%.

Cu: 0.05 to 1.0%
Cu is dissolved to improve the strength after brazing and to improve the corrosion resistance by making the potential of the core material noble. Below the lower limit, the effect is insufficient, and when the upper limit is exceeded, the melting point decreases and the core material melts. For this reason, the above range is desirable for the Cu content. In addition, the more preferable range of Cu content is 0.1 to 0.7%.

Fe: 0.1 to 1.0%
Fe crystallizes or precipitates as an intermetallic compound, and improves the strength after brazing. It also promotes recrystallization during final annealing and brazing. If it is less than the lower limit, the effect is insufficient, and if it exceeds the upper limit, the corrosion rate becomes too fast. Further, the crystal grain size after the final annealing becomes too fine, and the erosion of the wax becomes remarkably large at the portion where the processing is not introduced at the time of molding. For these reasons, the above range is desirable for the Fe content. In addition, the more preferable range of Fe content is 0.2 to 0.5%.

Zr, Ti: 0.01 to 0.3%, Cr: 0.01 to 0.5%
Zr, Ti or Cr is dispersed as a fine intermetallic compound after brazing to improve the strength. If it is less than the lower limit, the effect is insufficient, and if it exceeds the upper limit, the workability decreases. Therefore, the content of these components is preferably in the above range.

Bi: 0.01 to 1.0%
Bi suppresses re-oxidation of the material surface and improves the wetting and spreading property of the brazing material. If it is less than the lower limit, the effect is insufficient, and even if the upper limit is exceeded, no further effect can be obtained. For this reason, the above range is desirable for the Bi content.

3. Clad material In the clad material used in the present invention, it is sufficient that the Al-Si brazing material is clad on at least one side, and one side and a double sided clad material can be properly used. In the double-sided clad material, the both sides of the core material may be clad with a brazing material, the brazing material is clad on one side, and other materials such as a sacrificial material are clad on the other side. It may be a thing.

4). Material of brazing target member Any commonly used aluminum alloy can be used as the brazing constituent member other than the brazing material without any problem.

5). Surface roughness of the brazing member In carrying out the present invention, it is difficult to supply oxygen from the outside to the contact adhesion portion which is the junction portion by increasing the contact adhesion state of the junction portion. Increases the ability to suppress oxidation of the material surface. The oxygen supply here does not mean oxygen in the air atmosphere, but indicates that oxygen is slightly contained in the non-oxidizing atmosphere. As a result of investigations by the present inventors, it has been found that if the surface roughness of both joining members in the joint portion is Ra 0.3 μm or less, better joining can be obtained, and more preferably, Ra 0.25 μm or less is stable. It was also found that a good bonding state can be obtained. When the surface roughness exceeds Ra 0.3 μm, brazing performance is deteriorated because sufficient confidentiality cannot be obtained even if the pressure adhesion is increased.

6). Initial oxide film thickness of brazed component In carrying out the present invention, since it is not necessary to produce a material that suppresses the initial oxide film on the surface of the material in particular, it can usually be produced as a mass production coil material of aluminum. An aluminum material having an oxide film thickness of about 20 to 500 mm can be used. If it is less than 20 mm, acid cleaning or the like as shown in the prior art is required, and if it exceeds 500 mm, the oxide film destruction action by Mg cannot be sufficiently obtained, and it becomes difficult to obtain a good bonding state.

7). In-furnace atmosphere In carrying out the present invention, the atmosphere in the furnace is changed to a non-oxidizing gas such as an inert gas or a reducing gas, thereby reducing the oxygen concentration and dew point in the atmosphere and It is necessary to suppress oxidation. The type of replacement gas to be used is not particularly limited in obtaining bonding, but from the viewpoint of cost, nitrogen, argon, and hydrogen, ammonia, and carbon monoxide are used as the inert gas and the reducing gas, respectively. Is preferred. The oxygen concentration management range in the atmosphere is preferably 5 to 500 ppm. If it is less than 5 ppm, there is no problem in the joining, but there is a concern that the manufacturing cost will increase, such as using a large amount of gas for managing the atmosphere. If the content exceeds 500 ppm, the reoxidation of the brazed member is likely to proceed, and in particular, it is not possible to sufficiently obtain a bond between the bare component member having no brazing material on the surface and the brazing material.

8). Brazing temperature In the present invention, brazing can be performed at the lowest solidus temperature of 559 ° C. of the brazing material Al—Si—Mg alloy, and naturally, the brazing temperature range by the conventional Al—Si brazing material is also used. Is possible. Specifically, 559-620 degreeC is good. If it is less than 559 degreeC, the melting | fusing of a brazing cannot be obtained and brazing cannot be obtained. If it exceeds 620 ° C., the wax erosion becomes remarkable, which causes a problem in maintaining the product shape and the like, which is not preferable. However, even in this temperature range, if the solidus temperature is low due to the alloy composition of the brazing, brazing erosion may become prominent. In this case, the brazing temperature suitable for the alloy composition within this temperature range. Is preferably selected.

  In the present invention, an appropriate amount of Mg added to the brazing material breaks down the oxide film on the contact surface of the joint portion and suppresses reoxidation, so that good bonding can be obtained. This mechanism itself is the same as the conventional technology that proposes vacuum brazing, fluxless brazing under atmospheric pressure, etc. However, in vacuum brazing, it is essential to maintain a vacuum to prevent reoxidation of members. In addition, in the prior art under atmospheric pressure, an anti-oxidation layer is provided on the surface of the brazing material, or the brazed member is covered and surrounded to prevent re-oxidation of the material and diffusion of Mg vapor. There is a need to do. On the other hand, in the present invention, the component members to be bonded are reliably brought into contact with each other, then a certain amount or more of Mg is added to the brazing material, and further brazing is performed in a non-oxidizing atmosphere. A condition has been found in which the oxide film destruction activity by Mg exceeds the surface reoxidation power, and even when the brazing material is located on the outermost surface of the brazing component, the bonding is established. At this time, Mg added to the brazing material lowers the melting point of the brazing, and the effect that the getter action of Mg and the melting of the brazing (including local melting) occur in almost the same temperature range can be obtained, thereby improving the brazing property. ing.

  As described above, if the brazing method according to the present invention is used, fluxless brazing at atmospheric pressure is possible without the need for flux and vacuum equipment, and Mg is added to brazed components other than the brazing material. Even if added, it does not become a brazing-inhibiting factor, so that it is possible to develop applications for aluminum high-strength members for heat exchangers in which Mg is added to the structural members. In addition, since heating is performed in an atmosphere without decompression, Mg and Zn evaporation from the aluminum material stops around the product, and there is an advantage that contamination of the furnace inner wall and the like hardly occurs.

Hereinafter, an embodiment of the present invention will be described.
An Al—Si brazing material containing 0.1 to 5.0% Mg and 3 to 13% Si and a core material can be manufactured by a conventional method, and both or a sacrificial material. Clad rolling with other materials. The production conditions in the clad rolling are not particularly limited as the present invention. Further, the cladding ratio of each layer is not specified as the present invention.
As described above, the composition of the core material is Si: 0.1 to 1.2%, Mg: 0.01 to 2.0%, Mn: 0.2 to 2.5%, Cu : 0.05 to 1.0%, Si: 0.1 to 1.2%, Fe: 0.1 to 1.0%, or Si: 0.1 to 1.2%, Mg: 0.01-2.0%, Mn: 0.2-2.5%, Cu: 0.05-1.0%, Fe: 0.1-1.0% 2 or more types, and if desired, Zr: 0.01 to 0.3%, Ti: 0.01 to 0.3%, Cr: 0.01 to 0.5%, Bi: 0.01 to 1 It is desirable to contain one or more of 0.0%.
In the present invention, among the number of Si particles contained in the Al—Si brazing material having an equivalent circle diameter of 0.8 μm or more, the number of particles having a diameter of 1.75 μm or more is 25% or more. Is desirable. In order to obtain this material, in producing a cast slab of brazing filler metal, the cooling rate is set to a range slower than 10 ° C./sec, and the Si particle size generated by solidification cooling is coarsened. Even if the Si particles are crushed, the above conditions can be satisfied. However, even when this cooling rate is higher than 10 ° C./sec, Si particles can be coarsened by applying a heat treatment for several hours under conditions of 500 ° C. or higher as a homogenization treatment after casting, as described above. In addition, it is possible to obtain the Si particle size of the present invention after rolling.
In the present invention, it is desirable that the surface roughness of at least the contact adhesion portion surface of the aluminum clad material and the brazing target member is Ra 0.3 μm or less. This surface roughness depends on the roll surface roughness at the time of final rolling of the material, and can be obtained by setting the roll surface roughness to Ra of 0.45 μm or less. In addition, when the brazed joint portion is a heat exchanger member processed surface such as a press, the target surface roughness can be obtained by similarly controlling the die surface roughness of the press.

In the aluminum clad material obtained by a conventional method, the Al—Si brazing material is located on the outermost surface, and an oxide film having an initial oxide film thickness of 20 to 500 mm is formed.
The aluminum clad material is assembled with a member to be brazed such as a bare fin or a solid material connector, and preferably constitutes a heat exchanger assembly or the like. Note that aluminum materials having various compositions can be used as the brazing target member, and the present invention is not limited to a specific one.

The assembly is placed in a heating furnace having a non-oxidizing atmosphere without decompression. The non-oxidizing atmosphere can be configured using an inert gas such as nitrogen or argon, or a reducing gas such as hydrogen, ammonia or carbon monoxide, or a mixed gas thereof. The non-oxidizing atmosphere is not at reduced pressure during brazing heating and is usually at atmospheric pressure. In addition, before obtaining a non-oxidizing atmosphere, you may include a pressure reduction process for the purpose of substitution. The heating furnace does not need to have a sealed space, and may have a brazing material carry-in port and a carry-out port. Even in such a heating furnace, the non-oxidizing property is maintained by continuously blowing the inert gas into the furnace. The non-oxidizing atmosphere preferably has an oxygen concentration of 5 to 500 ppm by volume.
It brazes by heating at 559-620 degreeC under the said atmosphere. In brazing, the contact and adhesion portion with the brazing target member is satisfactorily joined without flux.

  An aluminum clad material clad with an Al-Si brazing material having the composition shown in Tables 1 to 3 (remainder Al and inevitable impurities) and a core material having the composition shown in Tables 1 to 3 (remainder Al and inevitable impurities) Prepared as. The Si particle diameter in the brazing material changes the cooling rate during casting in the range of 0.5 to 10 ° C./sec, and the material surface roughness indicates the roll surface roughness during final rolling by Ra 0.05 to 0. .Varying by changing in the range of 90.

The aluminum clad material was prepared by brazing various composition brazing materials and various composition core materials to a brazing material clad rate of 10% and a tempering equivalent to H14 to a thickness of 0.5 mm.
Further, as a brazing target member, a fin material made of JIS A3003 alloy and H14 aluminum bare material (thickness: 0.1 mm) was prepared.

O Brazing property A flat electro-sewn tube having a width of 20 mm was manufactured using the aluminum clad material of the present invention, and combined with a corrugated fin of JIS A3003 bare material to form a core shape. The core size is a core having 15 tubes and a length of 300 mm.
The core was heated to 560 to 600 ° C. in a brazing furnace in a nitrogen atmosphere (oxygen content: 15 ppm), and brazing properties were evaluated in the brazed state. The brazing property was evaluated based on the superiority or inferiority of the joining rate obtained by the following formula.

Fin joint rate = (total brazing length of fin and tube / total contact length of fin and tube) × 100
The brazing performance is determined by the fin joint rate after brazing (◎: 95% or more, ○: 85% or more, Δ: 80% or more, ×: less than 80%), and the results are shown in Tables 1 to 3. Indicated.

Material Strength The manufactured clad material (0.5 mm thickness) was a JIS No. 5 test piece, and subjected to a tensile test after brazing heat treatment and after aging treatment at 90 ° C. for 7 days. The obtained material strength measurement values were evaluated, and the results are shown in Tables 1 to 3.

About the produced clad material, the outermost surface of the brazing material is ground with # 1000 emery paper, then mirror-finished with 0.1 μm abrasive grains, and EPMA (electron beam micrometer) is observed in the observation field of surface direction of 10,000 μm ² (equivalent to 100 μm square). Fully automatic particle analysis using an analyzer was performed. The ratio of particles with a particle size of 1.75 μm or more out of the total number of particles of 0.8 μm or more measured is shown in the table.

While all of the examples showed good brazing properties, the comparative example did not provide sufficient bonding. Further, in the examples, it was possible to achieve both high material strength and brazing, but the conditions were not obtained with the comparative material.
Further, in the reference example in which the core component deviated from the preferred range, various problems were observed.

That is, among the fluxless brazing methods of the aluminum material of the present invention, the first present invention contains, by mass%, 0.1 to 5.0% Mg and 3 to 13% Si, with the balance being Al. A brazing method using an aluminum clad material that is clad on a core material and is located on the outermost surface, and in the non-oxidizing atmosphere without decompression , the Al-Si type The brazing material and the brazing target member are brought into contact and contact with each other, and at a heating temperature of 559 to 620 ° C., the core material and the brazing target member are bonded to each other at the contact surface of the contact close contact portion without flux by the Al—Si brazing material. It is characterized by joining.

A fluxless brazing method for an aluminum material according to a fourth aspect of the present invention is the method according to any one of the first to third aspects, wherein the Al-Si brazing material is 0.01% to 1.0% by mass. Bi is contained.
A fluxless brazing method for an aluminum material according to a fifth aspect of the present invention is the method according to any one of the first to fourth aspects, wherein the Al-Si brazing material is 0.1% to 5.0% by mass. Zn is contained.

In the fluxless brazing method of the aluminum material of the sixth aspect of the present invention, in any one of the first to fifth aspects of the present invention, the core material on which the Al-Si brazing material is clad is in mass%, It contains Si: 0.1 to 1.2%, Mg: 0.01 to 2.0%, and has a composition composed of the balance Al and inevitable impurities.

The fluxless brazing method of the aluminum material of the seventh aspect of the present invention is the flux material brazing method according to any one of the first to fifth aspects of the present invention, in which the core material clad with the Al-Si brazing material is in mass%, Mn: 0.2-2.5%, Cu: 0.05-1.0%, Si: 0.1-1.2%, Fe: 0.1-1.0%, the balance Al And a composition comprising inevitable impurities.

In the fluxless brazing method of the aluminum material of the eighth invention, in any one of the first to fifth inventions, the core material on which the Al—Si brazing material is clad is in mass%, Si: 0.1 to 1.2%, Mg: 0.01 to 2.0%, Mn: 0.2 to 2.5%, Cu: 0.05 to 1.0%, Fe: It is characterized by containing one or more of 0.1 to 1.0% and having a composition composed of the balance Al and inevitable impurities.

In the fluxless brazing method of the aluminum material of the ninth aspect of the present invention, in any one of the first to fifth aspects of the present invention, the core material on which the Al—Si based brazing material is clad is mass%, Si: 0.1 to 1.2%, Mg: 0.01 to 2.0%, Mn: 0.2 to 2.5%, Cu: 0.05 to 1.0%, Fe: It contains one or more of 0.1 to 1.0%, Zr: 0.01 to 0.3%, Ti: 0.01 to 0.3%, Cr: 0.01 to 0 0.5%, Bi: 0.01 to 1.0% of one or more of them, and having a composition composed of the balance Al and inevitable impurities.

An aluminum clad material for fluxless brazing according to a tenth aspect of the present invention is an Al-Si based brazing material comprising the Al-Si brazing material according to any one of the first to fifth aspects of the present invention clad on a core material. The material is located on the outermost surface, and the Al-Si brazing material is brought into contact and contact with the brazing target member in a non-oxidizing atmosphere without decompression, and the Al-Si brazing material is used to bring the Al-Si brazing material into contact with the contact surface. It is used for fluxless brazing so as to join the member to be brazed.

Fluxless brazing of aluminum clad material of the present invention eleventh, and characterized in that in the invention of claim 10, having a composition wherein the core material according to any one of the present invention of claim 6 to 9 To do.

That is, in the fluxless brazing method of the aluminum material of the present invention, the first present invention contains, by mass%, 0.1 to 5.0% Mg, 3 to 13% Si, and the balance being Al. And a brazing method using an aluminum clad material that is clad on the core material and is located on the outermost surface. The Si particles contained in the Al-Si braze material are: In the observation in the layer surface direction, among the number of equivalent circle diameters having a diameter of 0.8 μm or more, the number of those having a diameter of 1.75 μm or more is 25% or more, and in the non-oxidizing atmosphere without decompression, The Al-Si brazing material and the member to be brazed are brought into contact and intimate contact with each other, and the core material and the brazing are formed on the contact surface of the contact adhesion portion with the Al-Si brazing material at a heating temperature of 559 to 620 ° C. without flux. versus It is characterized by joining an elephant member.

The fluxless brazing method of the aluminum material of the second aspect of the present invention is the method according to the first aspect of the present invention, wherein the surface roughness of at least the contact adhesion portion surface of the aluminum clad material and the member to be brazed is Ra0. It is characterized by being 3 μm or less.

A fluxless brazing method for an aluminum material according to a third aspect of the present invention is the method according to any one of the first and second aspects, wherein the Al-Si brazing material is 0.01% to 1.0% by mass. Bi is contained.
A fluxless brazing method for an aluminum material according to a fourth aspect of the present invention is the method according to any one of the first to third aspects, wherein the Al-Si brazing material is 0.1% to 5.0% by mass. Zn is contained.

In the fluxless brazing method of the aluminum material of the fifth invention, the core material in which the Al-Si brazing material is clad in any one of the first to fourth inventions is in mass%, It contains Si: 0.1 to 1.2%, Mg: 0.01 to 2.0%, and has a composition composed of the balance Al and inevitable impurities.

In the fluxless brazing method of the aluminum material of the sixth aspect of the present invention, in any one of the first to fourth aspects of the present invention, the core material on which the Al-Si brazing material is clad is in mass%, Mn: 0.2-2.5%, Cu: 0.05-1.0%, Si: 0.1-1.2%, Fe: 0.1-1.0%, the balance Al And a composition comprising inevitable impurities.

The fluxless brazing method of the aluminum material of the seventh aspect of the present invention is the flux material brazing method according to any one of the first to fourth aspects of the present invention, wherein the core material on which the Al-Si brazing material is clad is in mass%, Si: 0.1 to 1.2%, Mg: 0.01 to 2.0%, Mn: 0.2 to 2.5%, Cu: 0.05 to 1.0%, Fe: It is characterized by containing one or more of 0.1 to 1.0% and having a composition composed of the balance Al and inevitable impurities.

The fluxless brazing method of the aluminum material according to the eighth aspect of the present invention, in any one of the first to fourth aspects of the present invention, the core material clad with the Al-Si brazing material is in mass%, Si: 0.1 to 1.2%, Mg: 0.01 to 2.0%, Mn: 0.2 to 2.5%, Cu: 0.05 to 1.0%, Fe: It contains one or more of 0.1 to 1.0%, Zr: 0.01 to 0.3%, Ti: 0.01 to 0.3%, Cr: 0.01 to 0 0.5%, Bi: 0.01 to 1.0% of one or more of them, and having a composition composed of the balance Al and inevitable impurities.

An aluminum clad material for fluxless brazing according to a ninth aspect of the present invention is an Al-Si based brazing material obtained by cladding the Al-Si based brazing material according to any one of the first to fourth aspects of the present invention on a core material. The material is located on the outermost surface, and the Al-Si brazing material is brought into contact and contact with the brazing target member in a non-oxidizing atmosphere without decompression, and the Al-Si brazing material is used to bring the Al-Si brazing material into contact with the contact surface. It is used for fluxless brazing so as to join the member to be brazed.

Fluxless brazing of aluminum clad material of the present invention of a 10 and characterized by the present invention of the ninth, having a composition wherein the core material according to any one of the present invention of the fifth to eighth To do.

Claims (10)

  A brazing method using an aluminum clad material in which an Al-Si brazing material containing 0.1 to 5.0% Mg and 3 to 13% Si is located on the outermost surface in mass%, and is accompanied by decompression. A fluxless brazing method for an aluminum material, wherein a contact adhesion portion with a brazing target member is joined by the Al-Si brazing material at a heating temperature of 559 to 620 ° C in a non-oxidizing atmosphere.   Of the number of particles having an equivalent circle diameter of 0.8 μm or more, the number of particles having a diameter of 1.75 μm or more is 25% in the observation in the surface layer direction of the Si particles contained in the Al—Si brazing material. The fluxless brazing method for an aluminum material according to claim 1, which is as described above.   3. The fluxless brazing of an aluminum material according to claim 1, wherein the surface roughness of at least the contact adhesion portion surface of the aluminum clad material and the brazing target member is Ra 0.3 μm or less. Method.   The flux-less brazing method for an aluminum material according to any one of claims 1 to 3, wherein the Al-Si brazing material contains 0.01 to 1.0% Bi by mass.   The core material in which the Al—Si brazing material is clad contains, by mass%, Si: 0.1 to 1.2%, Mg: 0.01 to 2.0%, the balance Al and inevitable impurities The fluxless brazing method for an aluminum material according to any one of claims 1 to 4, wherein the aluminum material has a composition comprising:   The core material on which the Al—Si brazing material is clad is mass%, Mn: 0.2 to 2.5%, Cu: 0.05 to 1.0%, Si: 0.1 to 1. The fluxless aluminum material according to any one of claims 1 to 4, characterized by comprising 2%, Fe: 0.1 to 1.0%, and having a composition comprising the balance Al and inevitable impurities. Brazing method.   The core material in which the Al—Si brazing material is clad contains, by mass%, Si: 0.1 to 1.2%, Mg: 0.01 to 2.0%, and Mn: 0.00. 2 to 2.5%, Cu: 0.05 to 1.0%, Fe: One or more of 0.1 to 1.0%, and a composition comprising the balance Al and inevitable impurities The fluxless brazing method for an aluminum material according to any one of claims 1 to 4, further comprising:   The core material in which the Al—Si brazing material is clad contains, by mass%, Si: 0.1 to 1.2%, Mg: 0.01 to 2.0%, and Mn: 0.00. 2 to 2.5%, Cu: 0.05 to 1.0%, Fe: 0.1 to 1.0%, or one or more of Zr: 0.01 to 0.3 %, Ti: 0.01 to 0.3%, Cr: 0.01 to 0.5%, Bi: 0.01 to 1.0%, or one or more of them, and the balance is inevitable with Al The fluxless brazing method for an aluminum material according to any one of claims 1 to 4, which has a composition comprising impurities.   The Al-Si brazing material according to any one of claims 1 to 4 is clad on a core material, and the Al-Si brazing material is located on the outermost surface, and is fluxed in a non-oxidizing atmosphere without decompression. An aluminum clad material for flux-less brazing, which is used for brazing of loess.   The aluminum clad material for fluxless brazing according to claim 9, wherein the core material has the composition described in any one of claims 5 to 8.