WO2013024732A1 - Aluminum alloy fin material for heat exchanger offering excellent post-brazing strength and corrosion resistance - Google Patents

Aluminum alloy fin material for heat exchanger offering excellent post-brazing strength and corrosion resistance Download PDF

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Publication number
WO2013024732A1
WO2013024732A1 PCT/JP2012/069962 JP2012069962W WO2013024732A1 WO 2013024732 A1 WO2013024732 A1 WO 2013024732A1 JP 2012069962 W JP2012069962 W JP 2012069962W WO 2013024732 A1 WO2013024732 A1 WO 2013024732A1
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aluminum alloy
fin material
mass
brazing
heat exchanger
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PCT/JP2012/069962
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French (fr)
Japanese (ja)
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尾崎　良太
小山　高弘
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住友軽金属工業株式会社
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Publication of WO2013024732A1 publication Critical patent/WO2013024732A1/en

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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C21/00—Alloys based on aluminium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C21/00—Alloys based on aluminium
    • C22C21/10—Alloys based on aluminium with zinc as the next major constituent
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F21/00—Constructions of heat-exchange apparatus characterised by the selection of particular materials
    • F28F21/08—Constructions of heat-exchange apparatus characterised by the selection of particular materials of metal
    • F28F21/081—Heat exchange elements made from metals or metal alloys
    • F28F21/084—Heat exchange elements made from metals or metal alloys from aluminium or aluminium alloys

Definitions

  • the present invention relates to an aluminum alloy fin material for a heat exchanger that is excellent in strength after brazing and susceptibility to intergranular corrosion, and in particular, as a constituent material of a working fluid passage such as a radiator or a car air conditioner, a fluoride is used.
  • a fluoride is used as a constituent material of a working fluid passage such as a radiator or a car air conditioner.
  • the present invention relates to an excellent aluminum alloy fin material. Especially suitable for fin materials used with thin wall.
  • Aluminum alloy heat exchangers are widely used as heat exchangers for automobiles such as radiators, heaters, oil coolers, intercoolers, evaporators and condensers for air conditioners, and oil coolers for hydraulic equipment and industrial machinery. ing.
  • the fin material of this aluminum alloy heat exchanger is required to have a sacrificial anode effect for corrosion protection of the tube material whose inner surface serves as a passage for the working fluid (refrigerant), and at the time of brazing heating for manufacturing the core, Brazing joint properties such as suppressing buckling deformation and brazing erosion at high temperatures are required.
  • Mn such as Al—Mn series, Al—Mn—Si series, Al—Mn—Si—Cu series such as JIS-A3003 and JIS-A3203 is used.
  • the aluminum alloy fin material contained is used.
  • a technique of adding a base such as Zn, Sn, In or the like to make it base electrochemically is used.
  • Patent Document 1 Japanese Patent Laid-Open No. 14-1613273
  • the fin material disclosed in Patent Document 1 has a limit in improving strength because of low Cu content.
  • Patent Document 2 JP-A-10-81932
  • Patent Document 3 JP-A-06-108195
  • the aluminum alloys for fins shown in Patent Document 2 and Patent Document 3 have a high Zn content, and therefore there is a problem that intergranular corrosion is likely to occur when the Cu content is high.
  • heat exchangers of various sizes are often brazed and heated in the same line, and if the same heating as a large heat exchanger that is difficult to raise the temperature is performed, the small heat exchanger The rate of temperature increase is increased, and the fin portion may be exposed to a high temperature. For this reason, when a high-strength material is used, the solidus temperature of the material becomes low, and there is a problem that the fins melt during brazing heating, so it is difficult to ensure brazing and corrosion resistance.
  • Patent Document 4 Japanese Patent Laid-Open No. 14-161324 has a fibrous structure, a fine recrystallized grain structure is likely to be formed by brazing heating, and the fin is likely to buckle during brazing. And there is a problem that intergranular corrosion is likely to occur.
  • JP 2002-161323 A Japanese Patent Laid-Open No. 10-81932 Japanese Patent Laid-Open No. 06-108195 JP 2002-161324 A
  • the object of the present invention is to improve the above-mentioned problems associated with the thinning of aluminum alloy fins for heat exchangers and to satisfy the demand for improvement.
  • Another object of the present invention is to provide an aluminum alloy fin material for heat exchangers that is excellent.
  • the present invention examines the relationship between brazing properties, strength characteristics, sacrificial anode effect, intergranular corrosion sensitivity, and alloy components, combinations of alloy components, material strength properties, internal structure, etc.
  • good brazing and sacrificing while improving the strength of the fin material by controlling the structure of the matrix of the fin material by controlling the amount of Cu and Zn added appropriately It was possible to secure the anode effect and reduce the intergranular corrosion sensitivity.
  • the present invention (1) includes 1.0 to 2.0% by mass of Mn, 0.5 to 1.3% by mass of Si, 0.1 to 0.8% by mass of Fe, 0.20% by mass. It is an aluminum alloy fin material containing more than 0.4 mass% Cu, 1.1 mass% or more and less than 2.0 mass% Zn, the balance being Al and inevitable impurities, and the matrix of the aluminum alloy fin material is The present invention provides an aluminum alloy fin material for a heat exchanger that has a recrystallized structure and is excellent in strength and corrosion resistance after brazing.
  • the aluminum alloy fin material for a heat exchanger further comprises 0.05 to 0.3% by mass of Zr, 0.05 to 0.3% by mass of Cr, and 0.06 to 0%. It provides an aluminum alloy fin material for a heat exchanger excellent in strength and corrosion resistance after brazing according to (1), containing one or more of 35 mass% Ti. .
  • the present invention (3) is characterized in that the aluminum alloy fin material for heat exchanger further contains 0.05 to 0.2% by mass of Mg.
  • the present invention provides an aluminum alloy fin material for a heat exchanger that is excellent in strength and corrosion resistance after brazing.
  • an aluminum alloy fin material for a heat exchanger that is excellent in brazeability and strength after brazing and has excellent intergranular corrosion resistance.
  • the present invention relates to 1.0 to 2.0 mass% Mn, 0.5 to 1.3 mass% Si, 0.1 to 0.8 mass% Fe, more than 0.20 mass% and 0.4 mass % Of Cu, 1.1 mass% or more and less than 2.0 mass% of Zn, the balance being an aluminum alloy fin material made of Al and inevitable impurities, and the matrix of the aluminum alloy fin material is a recrystallized structure
  • This is an aluminum alloy fin material for heat exchangers having excellent strength and corrosion resistance after brazing.
  • the aluminum alloy fin material for heat exchanger according to the present invention contains Mn.
  • Mn forms an Al-Mn-Si compound by coexisting with Si to improve the strength of the fin material before and after brazing, as well as good high temperature buckling resistance and moldability.
  • the Mn content of the aluminum alloy fin material for heat exchanger according to the present invention is 1.0 to 2.0% by mass, preferably 1.3 to 1.8% by mass. If the content of Mn is less than the above range, the effect of Mn becomes too small, and if it exceeds the above range, a coarse compound is produced at the time of casting, and rolling workability is impaired, so that it is difficult to obtain a healthy plate material. .
  • the aluminum alloy fin material for heat exchanger according to the present invention contains Si. Si coexists with Mn to produce an Al—Mn—Si based compound, thereby improving the strength of the fin material.
  • the Si content in the aluminum alloy fin material for a heat exchanger according to the present invention is 0.5 to 1.3% by mass, preferably 0.7 to 1.1% by mass. If the Si content is less than the above range, the effect of Si is too small. If it exceeds the above range, the melting point of the fin material is lowered, and local melting tends to occur during brazing.
  • the aluminum alloy fin material for heat exchanger according to the present invention contains Fe.
  • Fe improves the strength of the fin material before and after brazing and improves the moldability.
  • the content of Fe in the aluminum alloy fin material for heat exchanger according to the present invention is 0.1 to 0.8% by mass, preferably 0.1 to 0.4% by mass. If the Fe content is less than the above range, the effect of Fe becomes too small, and if it exceeds the above range, it becomes a cathode for the aluminum base material and the corrosion resistance is low.
  • the aluminum alloy fin material for a heat exchanger according to the present invention contains Cu.
  • Cu improves the strength before brazing and after brazing and improves the moldability.
  • the content of Cu in the aluminum alloy fin material for a heat exchanger according to the present invention is more than 0.20 mass% and 0.4 mass% or less, preferably 0.25 to 0.35 mass%. If the Cu content is less than the above range, the effect of Cu becomes too small. If the Cu content exceeds the above range, the potential of the fin material is made noble, the sacrificial anode effect is lowered, the melting point is lowered, and local melting is likely to occur during brazing.
  • the aluminum alloy fin material for heat exchanger according to the present invention contains Zn.
  • Zn lowers the potential in the fin material and provides a sacrificial anode effect.
  • the Zn content in the aluminum alloy fin material for a heat exchanger according to the present invention is 1.1 mass% or more and less than 2.0 mass%, preferably 1.5 to 1.9 mass%. If the Zn content is less than the above range, the effect of Zn becomes too small. Further, if the Zn content exceeds the above range, the intergranular corrosion sensitivity becomes high, the melting point is lowered, and local melting is likely to occur during brazing.
  • the aluminum alloy fin material for a heat exchanger according to the present invention further includes 0.05 to 0.3% by mass of Zr, 0.05 to 0.3% by mass of Cr, and 0.06 to 0.35% by mass of Ti. 1 type or 2 types or more can be contained.
  • Zr coarsens the grain size after brazing and improves high temperature buckling resistance and brazing.
  • content of Zr is less than 0.05% by mass, there is no effect of Zr.
  • content of Zr exceeds 0.3% by mass, a coarse compound is produced and it becomes difficult to produce a normal plate material.
  • Cr increases the crystal grain size after brazing and improves high temperature buckling resistance and brazing.
  • the Cr content is less than 0.05% by mass, there is no effect of Cr.
  • the Cr content exceeds 0.3% by mass, a coarse compound is produced, and it becomes difficult to produce a normal plate material.
  • Ti is divided into a high-concentration region and a low region in the plate thickness direction of the fin material, and becomes a layered form in which they are alternately distributed, thereby increasing the corrosion-proof life of the fin material.
  • the Ti content is less than 0.06% by mass, there is no effect of Ti.
  • the Ti content exceeds 0.35% by mass, a coarse compound is produced, making it difficult to produce a normal plate material.
  • the aluminum alloy fin material for a heat exchanger according to the present invention may further contain 0.2% by mass or less of Mg.
  • Mg has the effect of improving the strength of the fin material before brazing and after brazing, and the effect is small at less than 0.05% by mass, but from the viewpoint of lowering brazing properties, the content is 0.2. Limited to mass% or less.
  • the Mg content exceeds 0.2% by mass, the Mg reacts with the fluoride-based flux and inhibits brazing with the fin material.
  • Mg fluoride is generated and the appearance of the brazed portion is deteriorated.
  • the matrix of the aluminum alloy fin material for heat exchanger according to the present invention has a recrystallized structure. Since the matrix of the aluminum alloy fin material for heat exchanger according to the present invention has a recrystallized structure, the crystal grain size after brazing becomes large, so that the brazing material hardly penetrates along the grain boundary, and is resistant to high temperatures. Buckling is improved. On the other hand, when the matrix is a fiber structure, the crystal grain size after brazing becomes smaller, and the high temperature buckling resistance is lowered due to the occurrence of erosion. This is a method for producing an aluminum alloy fin material for a heat exchanger according to the present invention.
  • hot rolling, cold rolling, intermediate annealing, and cold rolling are performed to obtain a heat having a predetermined thickness.
  • An aluminum alloy fin material for an exchanger can be obtained.
  • hot rolling may be performed as it is, or it may be cooled to room temperature and reheated for hot rolling.
  • the matrix of a fin material can be made into a recrystallized structure by selecting suitably the intermediate annealing time, the cooling rate after intermediate annealing, the cold work degree after intermediate annealing, and the like.
  • the recrystallization completion temperature of the fin material is the composition of the fin material, the homogenization treatment temperature and the homogenization treatment time, the cooling rate after the homogenization treatment, the hot rolling start temperature and the hot rolling end temperature, and the cooling after the hot rolling. Since it changes depending on the degree of processing in the hot rolling, the intermediate annealing temperature is set accordingly.
  • the structure of the fin material it is possible to determine whether the structure is a recrystallized structure or a fiber structure by performing polishing and etching processes so that crystal grain boundaries can be observed and observing with an optical microscope.
  • the grain boundary can be clearly observed and the rolled structure whose structure is extended to a fiber is not observed, it is a recrystallized structure, while the grain boundary is not clearly observed and the rolled structure is observed.
  • it is discriminated as a fiber structure.
  • a recrystallized structure and a fiber structure are mixed, but a mixed recrystallized structure and a fiber structure is not preferable because the crystal grain size after brazing in the fiber structure region becomes small.
  • a heat exchanger can be manufactured by combining the aluminum alloy fin material for a heat exchanger of the present invention with a member constituting another heat exchanger such as a tube material or a plate material, and brazing and joining.
  • a tube material a brazing sheet strip in which a brazing material and a sacrificial anode material are clad on a core material is molded so that the brazing material is on the outside and the sacrificial anode material is on the inside, and the side end face is high-frequency welded into a circular tube,
  • a flat tube shape is used by roll forming.
  • a tube material a part of the end side of the plate is overlapped, or a part of the plate is bent so as to become an inner column of the tube, so that a flat tube shape is formed by brazing without welding. Things are also used.
  • a brazing filler metal powder such as Si powder can be coated on the outer surface of the extruded flat multi-hole tube and brazed to the fin material.
  • the brazing powder can be mixed with a powder having a flux component, a powder having a sacrificial anode effect, and a binder.
  • the plate material a plate in which a core material is clad with a brazing material or a sacrificial anode material is used as necessary, and is molded into a desired shape and used.
  • the core material of the brazing sheet used as the tube material is not particularly limited as long as it is used for a heat exchanger, but pure Al, Al—Cu alloy, Al—Mn alloy, Al— Examples thereof include Mn—Cu alloys and Al—Cu—Mn—Mg alloys.
  • the brazing material component may be any alloy as long as it has a melting point lower than that of the tube material or plate material, such as an Al—Si alloy, an Al—Si—Zn alloy, Examples thereof include an aluminum alloy powder containing Si such as an Al—Si—Cu alloy, a flux that contains Si such as K 2 SiF 6 and generates a brazing material when brazing.
  • the cooling rate after brazing is preferably 50 to 80 ° C./min from 550 ° C. to 450 ° C. If it is too slow, Cu-based precipitates are likely to precipitate along the grain boundaries, and intergranular corrosion tends to occur.
  • the aluminum alloy fin material for a heat exchanger of the present invention has a Cu content and a Zn content in appropriate ranges, and the matrix structure of the fin material is a recrystallized structure, so that the strength after brazing is high and High corrosion resistance.
  • Casting souls having the compositions shown in Tables 1 and 2 were cast by continuous casting. After homogenizing these alloys according to a conventional method, a plate (H14) having a thickness of 0.06 mm was manufactured through hot rolling, then cold rolling, intermediate annealing, and finish cold rolling. At this time, the structure of the aluminum alloy fin material was adjusted by adjusting the intermediate annealing temperature and the cold work degree.
  • the aluminum alloy fin material obtained as described above was evaluated for (1) structure and (2) melting point according to the following method.
  • the fin material was cooled from 550 ° C. to 450 ° C. at a cooling rate of 60 ° C./min.
  • (3) Tensile strength after brazing (4) Brazeability, (5) Self-corrosion resistance, (6) Intergranular corrosion sensitivity was evaluated.
  • brazing property A corrugated fin material, a JIS-A3003 alloy core material and a JIS-A4045 alloy brazing material 0.20 mm thick plate material assembled into a flat shape, After applying a fluoride flux with a concentration of 3% to the brazing material side surface of the tube material, brazing heating was performed at 605 ° C. for 3 minutes in a nitrogen gas atmosphere to produce a mini-core of the heat exchanger. About this minicore, the joint part of a fin material and a tube material was observed visually, and brazing was evaluated from the presence or absence of the buckling of a fin and fusion
  • the case where the self-corrosion of the fin is small is marked with ⁇
  • the case where the self-corrosion of the fin is large is marked with x.
  • a 2-hour immersion test was performed based on ISO / DIS11846, and the microstructure of the fin cross section was observed to investigate the intergranular corrosion of the fin. The case where the intergranular corrosion did not occur or the case where the intergranular corrosion was slight was marked with ⁇ , and the case where the intergranular corrosion was remarkable was marked with X.

Abstract

An aluminum alloy fin material for a heat exchanger offering excellent post-brazing strength and corrosion resistance, the aluminum alloy fin material containing 1.0 to 2.0 mass% Mn, 0.5 to 1.3 mass% Si, 0.1 to 0.8 mass% Fe, greater than 0.20 and up to 0.4 mass% Cu, and 1.1 to less than 2.0 mass% Zn, the remainder comprising Al and inevitable impurities; characterized in that the matrix of the aluminum alloy fin material is a recrystallized structure. According to the present invention, there can be provided an aluminum alloy fin material for a heat exchanger offering excellent brazability and post-brazing strength, and also excellent intergranular corrosion resistance.

Description

ろう付け後の強度及び耐食性に優れた熱交換器用アルミニウム合金フィン材Aluminum alloy fin material for heat exchangers with excellent strength and corrosion resistance after brazing
　本発明は、ろう付け後の強度及び耐粒界腐食感受性に優れた熱交換器用アルミニウム合金フィン材に関するものであり、特にラジエータやカーエアコン等のように、作動流体通路の構成材料を、フッ化物系フラックスを用いた不活性ガス雰囲気中ろう付けにより接合するアルミニウム合金製熱交換器用のフィン材として用いるにことに適した、ろう付け後の強度が高く、耐粒界腐食感受性、ろう付け性に優れたアルミニウム合金フィン材に関するものである。特に薄肉で使用されるフィン材に適する。 The present invention relates to an aluminum alloy fin material for a heat exchanger that is excellent in strength after brazing and susceptibility to intergranular corrosion, and in particular, as a constituent material of a working fluid passage such as a radiator or a car air conditioner, a fluoride is used. Suitable for use as a fin material for aluminum alloy heat exchangers joined by brazing in an inert gas atmosphere using a system flux. High strength after brazing, high resistance to intergranular corrosion, and brazing. The present invention relates to an excellent aluminum alloy fin material. Especially suitable for fin materials used with thin wall.
　アルミニウム合金製の熱交換器は、ラジエータ、ヒータ、オイルクーラ、インタークーラ及びエアコンのエバポレータやコンデンサ等の自動車用熱交換器あるいは油圧機器や産業機械のオイルクーラ等の熱交換器として、広く使用されている。このアルミニウム合金製熱交換器のフィン材には、内面が作動流体（冷媒）の通路となるチューブ材を防食するための犠牲陽極効果が要求されると共に、コアを製造するろう付け加熱時における、高温時の座屈変形やろうの侵食を抑えるなどのろう付け接合性が要求されている。このような要求を満たすために、従来、アルミニウム合金フィン材としてはＪＩＳ－Ａ３００３、ＪＩＳ－Ａ３２０３等のＡｌ－Ｍｎ系、Ａｌ－Ｍｎ－Ｓｉ系、Ａｌ－Ｍｎ－Ｓｉ－Ｃｕ系等のＭｎを含有するアルミニウム合金フィン材が用いられている。更に当該アルミニウム合金製フィン材に犠牲陽極効果を付与するために、Ｚｎ、Ｓｎ、Ｉｎ等を添加して電気化学的に卑にする手法が用いられている。 Aluminum alloy heat exchangers are widely used as heat exchangers for automobiles such as radiators, heaters, oil coolers, intercoolers, evaporators and condensers for air conditioners, and oil coolers for hydraulic equipment and industrial machinery. ing. The fin material of this aluminum alloy heat exchanger is required to have a sacrificial anode effect for corrosion protection of the tube material whose inner surface serves as a passage for the working fluid (refrigerant), and at the time of brazing heating for manufacturing the core, Brazing joint properties such as suppressing buckling deformation and brazing erosion at high temperatures are required. In order to satisfy such a requirement, conventionally, as an aluminum alloy fin material, Mn such as Al—Mn series, Al—Mn—Si series, Al—Mn—Si—Cu series such as JIS-A3003 and JIS-A3203 is used. The aluminum alloy fin material contained is used. Furthermore, in order to give the sacrificial anode effect to the fin material made of aluminum alloy, a technique of adding a base such as Zn, Sn, In or the like to make it base electrochemically is used.
　近年、自動車の軽量化の要請に伴い、自動車熱交換器においても省エネルギー、省資源の観点から構成材料の薄肉化が要請され、フィン材についても薄肉化が期待されている。フィン材の薄肉化は熱交換器の剛性に影響することから、ろう付け後の強度に優れたフィン材が求められており、ＪＩＳ－Ａ３００３合金にＦｅ、Ｃｕ、Ｚｎを添加したアルミニウム合金が提案されており（特許文献１：特開平１４－１６１３２３号）、ある程度の薄肉化は可能であった。しかし、一層の薄肉化を図るためには、熱交換器使用中のフィン倒れや変形を生じないために、ろう付け性やろう付け後強度、耐食性について一層の改善が必要である。特許文献１に示されているフィン材では、Ｃｕの含有量が少ないため、強度向上には限界があった。 In recent years, with the demand for reducing the weight of automobiles, automobile heat exchangers are also required to reduce the thickness of their constituent materials from the viewpoints of energy saving and resource saving, and the fin materials are also expected to be thinner. Since thinning the fin material affects the rigidity of the heat exchanger, a fin material with excellent strength after brazing is required, and an aluminum alloy with Fe, Cu, Zn added to JIS-A3003 is proposed. (Patent Document 1: Japanese Patent Laid-Open No. 14-161323), it was possible to reduce the thickness to some extent. However, in order to further reduce the thickness, it is necessary to further improve the brazing property, the strength after brazing, and the corrosion resistance in order not to cause fin collapse or deformation during use of the heat exchanger. The fin material disclosed in Patent Document 1 has a limit in improving strength because of low Cu content.
　ここで強度を向上させるため、フィン材用合金にＣｕを添加することは、強度の向上に寄与するものの、電位が貴化してしまうため、犠牲防食電位を確保するために、併せて電位を卑化するＺｎを多く含有したフィン用アルミニウム合金が開発されていた（特許文献２：特開平１０－８１９３２号、特許文献３：特開平０６－１０８１９５号）。しかし、特許文献２や特許文献３に示されているフィン用アルミニウム合金ではＺｎ含有量が多いため、Ｃｕ含有量が多い場合には粒界腐食が発生し易いという問題が生じていた。また、Ｃｕ、Ｚｎの添加範囲によっては、固相線温度の低下や自己腐食、粒界腐食の発生を引き起こすことがわかっており、Ｃｕ及びＺｎが多く添加されたアルミニウム合金においては、粒界腐食感受性が高くなり、使用中にフィンが脱落して熱交換性能の低下に影響する。 Here, in order to improve the strength, adding Cu to the alloy for the fin material contributes to the improvement of the strength, but the potential becomes noble. Therefore, in order to secure the sacrificial anticorrosive potential, the potential is also reduced. An aluminum alloy for fins containing a large amount of Zn to be converted has been developed (Patent Document 2: JP-A-10-81932, Patent Document 3: JP-A-06-108195). However, the aluminum alloys for fins shown in Patent Document 2 and Patent Document 3 have a high Zn content, and therefore there is a problem that intergranular corrosion is likely to occur when the Cu content is high. In addition, depending on the range of addition of Cu and Zn, it is known that the solidus temperature decreases, self-corrosion, and the occurrence of intergranular corrosion occurs. Sensitivity is increased, and fins fall off during use, affecting the deterioration of heat exchange performance.
　熱交換器の製造工程では、いろいろな寸法の熱交換器が同じラインでろう付け加熱される場合が多く、昇温しにくい大型の熱交換器と同じ加熱を行うと、小型の熱交換器は昇温速度が速くなり、特にフィン部が高温にさらされることもある。このため、強度の高い材料を用いた場合は、材料の固相線温度が低くなり、ろう付け加熱中にフィンが溶融してしまう問題も生じるため、ろう付け性や耐食性の確保が難しい。 In the heat exchanger manufacturing process, heat exchangers of various sizes are often brazed and heated in the same line, and if the same heating as a large heat exchanger that is difficult to raise the temperature is performed, the small heat exchanger The rate of temperature increase is increased, and the fin portion may be exposed to a high temperature. For this reason, when a high-strength material is used, the solidus temperature of the material becomes low, and there is a problem that the fins melt during brazing heating, so it is difficult to ensure brazing and corrosion resistance.
　また、特許文献４：特開平１４－１６１３２４号に示されるフィン材では、繊維状組織であるため、ろう付け加熱により微細な再結晶粒組織になりやすく、ろう付け時にフィンが座屈しやすいという問題や粒界腐食が生じやすいという問題があった。 Further, since the fin material disclosed in Patent Document 4: Japanese Patent Laid-Open No. 14-161324 has a fibrous structure, a fine recrystallized grain structure is likely to be formed by brazing heating, and the fin is likely to buckle during brazing. And there is a problem that intergranular corrosion is likely to occur.
特開２００２－１６１３２３号公報JP 2002-161323 A 特開平１０－８１９３２号公報Japanese Patent Laid-Open No. 10-81932 特開平０６－１０８１９５号公報Japanese Patent Laid-Open No. 06-108195 特開２００２－１６１３２４号公報JP 2002-161324 A
　本発明の目的は、熱交換器用アルミニウム合金フィン材の薄肉化に伴う上記の問題点を改善し改善要求を満足するために、ろう付け性及びろう付け後の強度に優れ、耐粒界腐食性にも優れた熱交換器用アルミニウム合金製フィン材を提供することにある。 The object of the present invention is to improve the above-mentioned problems associated with the thinning of aluminum alloy fins for heat exchangers and to satisfy the demand for improvement. Another object of the present invention is to provide an aluminum alloy fin material for heat exchangers that is excellent.
　本発明は、上記課題を解決すべく、ろう付け性、強度特性、犠牲陽極効果、粒界腐食感受性と、合金成分、合金成分の組合せ、材料の強度特性、内部組織等との関連に検討を加えた結果としてなされたものであり、Ｃｕ添加量とＺｎ添加量を適正にし、フィン材のマトリックスの組織を制御することにより、フィン材としての強度を向上させながら、良好なろう付け性と犠牲陽極効果を確保するとともに、粒界腐食感受性を低減させることが実現できたものである。 In order to solve the above-mentioned problems, the present invention examines the relationship between brazing properties, strength characteristics, sacrificial anode effect, intergranular corrosion sensitivity, and alloy components, combinations of alloy components, material strength properties, internal structure, etc. As a result of the addition, good brazing and sacrificing while improving the strength of the fin material by controlling the structure of the matrix of the fin material by controlling the amount of Cu and Zn added appropriately It was possible to secure the anode effect and reduce the intergranular corrosion sensitivity.
　すなわち、本発明（１）は、１．０～２．０質量％のＭｎ、０．５～１．３質量％のＳｉ、０．１～０．８質量％のＦｅ、０．２０質量％超え０．４質量％以下のＣｕ、１．１質量％以上２．０質量％未満のＺｎを含有し、残部がＡｌ及び不可避不純物からなるアルミニウム合金フィン材であり、アルミニウム合金フィン材のマトリックスが再結晶組織であることを特徴とするろう付け後の強度と耐食性に優れた熱交換器用アルミニウム合金フィン材を提供するものである。 That is, the present invention (1) includes 1.0 to 2.0% by mass of Mn, 0.5 to 1.3% by mass of Si, 0.1 to 0.8% by mass of Fe, 0.20% by mass. It is an aluminum alloy fin material containing more than 0.4 mass% Cu, 1.1 mass% or more and less than 2.0 mass% Zn, the balance being Al and inevitable impurities, and the matrix of the aluminum alloy fin material is The present invention provides an aluminum alloy fin material for a heat exchanger that has a recrystallized structure and is excellent in strength and corrosion resistance after brazing.
　また、本発明（２）は、前記熱交換器用アルミニウム合金フィン材が、更に、０．０５～０．３質量％のＺｒ、０．０５～０．３質量％のＣｒ及び０．０６～０．３５質量％のＴｉのうちの１種又は２種以上を含有することを特徴とする（１）のろう付け後の強度と耐食性に優れた熱交換器用アルミニウム合金フィン材を提供するものである。 In the present invention (2), the aluminum alloy fin material for a heat exchanger further comprises 0.05 to 0.3% by mass of Zr, 0.05 to 0.3% by mass of Cr, and 0.06 to 0%. It provides an aluminum alloy fin material for a heat exchanger excellent in strength and corrosion resistance after brazing according to (1), containing one or more of 35 mass% Ti. .
　また、本発明（３）は、前記熱交換器用アルミニウム合金フィン材が、更に、０．０５～０．２質量％のＭｇを含有することを特徴とする（１）又は（２）いずれかのろう付け後の強度と耐食性に優れた熱交換器用アルミニウム合金フィン材を提供するものである。 In addition, the present invention (3) is characterized in that the aluminum alloy fin material for heat exchanger further contains 0.05 to 0.2% by mass of Mg. The present invention provides an aluminum alloy fin material for a heat exchanger that is excellent in strength and corrosion resistance after brazing.
　本発明によれば、ろう付け性及びろう付け後の強度に優れ、耐粒界腐食性にも優れた熱交換器用アルミニウム合金製フィン材を提供することができる。 According to the present invention, it is possible to provide an aluminum alloy fin material for a heat exchanger that is excellent in brazeability and strength after brazing and has excellent intergranular corrosion resistance.
　本発明は、１．０～２．０質量％のＭｎ、０．５～１．３質量％のＳｉ、０．１～０．８質量％のＦｅ、０．２０質量％超え０．４質量％以下のＣｕ、１．１質量％以上２．０質量％未満のＺｎを含有し、残部がＡｌ及び不可避不純物からなるアルミニウム合金フィン材であり、アルミニウム合金フィン材のマトリックスが再結晶組織であることを特徴とするろう付け後の強度と耐食性に優れた熱交換器用アルミニウム合金フィン材である。 The present invention relates to 1.0 to 2.0 mass% Mn, 0.5 to 1.3 mass% Si, 0.1 to 0.8 mass% Fe, more than 0.20 mass% and 0.4 mass % Of Cu, 1.1 mass% or more and less than 2.0 mass% of Zn, the balance being an aluminum alloy fin material made of Al and inevitable impurities, and the matrix of the aluminum alloy fin material is a recrystallized structure This is an aluminum alloy fin material for heat exchangers having excellent strength and corrosion resistance after brazing.
　本発明に係る熱交換器用アルミニウム合金フィン材は、Ｍｎを含有する。Ｍｎは、Ｓｉと共存することによりＡｌ－Ｍｎ－Ｓｉ系の化合物を生成して、ろう付け前及びろう付け後のフィン材の強度を向上させると共に、耐高温座屈性及び成形加工性を良好にする。本発明に係る熱交換器用アルミニウム合金フィン材のＭｎ含有量は、１．０～２．０質量％、好ましくは１．３～１．８質量％である。Ｍｎの含有量が、上記範囲未満だと、Ｍｎの効果が小さくなり過ぎ、また、上記範囲を超えると、鋳造時に粗大な化合物が生成し、圧延加工性が害される結果、健全な板材が得難い。 The aluminum alloy fin material for heat exchanger according to the present invention contains Mn. Mn forms an Al-Mn-Si compound by coexisting with Si to improve the strength of the fin material before and after brazing, as well as good high temperature buckling resistance and moldability. To. The Mn content of the aluminum alloy fin material for heat exchanger according to the present invention is 1.0 to 2.0% by mass, preferably 1.3 to 1.8% by mass. If the content of Mn is less than the above range, the effect of Mn becomes too small, and if it exceeds the above range, a coarse compound is produced at the time of casting, and rolling workability is impaired, so that it is difficult to obtain a healthy plate material. .
　本発明に係る熱交換器用アルミニウム合金フィン材は、Ｓｉを含有する。Ｓｉは、Ｍｎと共存してＡｌ－Ｍｎ－Ｓｉ系化合物を生成し、フィン材の強度を向上させる。本発明に係る熱交換器用アルミニウム合金フィン材のＳｉの含有量は、０．５～１．３質量％、好ましくは０．７～１．１質量％である。Ｓｉの含有量が、上記範囲未満だと、Ｓｉの効果が小さくなり過ぎ、また、上記範囲を超えると、フィン材の融点を下げ、ろう付け時に局部溶融が生じ易くなる。 The aluminum alloy fin material for heat exchanger according to the present invention contains Si. Si coexists with Mn to produce an Al—Mn—Si based compound, thereby improving the strength of the fin material. The Si content in the aluminum alloy fin material for a heat exchanger according to the present invention is 0.5 to 1.3% by mass, preferably 0.7 to 1.1% by mass. If the Si content is less than the above range, the effect of Si is too small. If it exceeds the above range, the melting point of the fin material is lowered, and local melting tends to occur during brazing.
　本発明に係る熱交換器用アルミニウム合金フィン材は、Ｆｅを含有する。Ｆｅは、ろう付け前及びろう付け後のフィン材の強度を向上させると共に成形加工性を良好にする。本発明に係る熱交換器用アルミニウム合金フィン材のＦｅの含有量は、０．１～０．８質量％、好ましくは０．１～０．４質量％である。Ｆｅの含有量が、上記範囲未満だと、Ｆｅの効果が小さくなり過ぎ、また、上記範囲を超えると、アルミニウム母材に対してカソードとなり耐食性が低くなる。 The aluminum alloy fin material for heat exchanger according to the present invention contains Fe. Fe improves the strength of the fin material before and after brazing and improves the moldability. The content of Fe in the aluminum alloy fin material for heat exchanger according to the present invention is 0.1 to 0.8% by mass, preferably 0.1 to 0.4% by mass. If the Fe content is less than the above range, the effect of Fe becomes too small, and if it exceeds the above range, it becomes a cathode for the aluminum base material and the corrosion resistance is low.
　本発明に係る熱交換器用アルミニウム合金フィン材は、Ｃｕを含有する。Ｃｕは、ろう付け前及びろう付け後の強度を向上させると共に、成形加工性を良好にする。本発明に係る熱交換器用アルミニウム合金フィン材のＣｕの含有量は、０．２０質量％を超え０．４質量％以下、好ましくは０．２５～０．３５質量％である。Ｃｕの含有量が、上記範囲未満だと、Ｃｕの効果が小さくなり過ぎる。また、Ｃｕの含有量が、上記範囲を超えると、フィン材の電位を貴にし、犠牲陽極効果が低くなり、また、融点が低下して、ろう付け時に局部的な溶融が生じ易くなる。 The aluminum alloy fin material for a heat exchanger according to the present invention contains Cu. Cu improves the strength before brazing and after brazing and improves the moldability. The content of Cu in the aluminum alloy fin material for a heat exchanger according to the present invention is more than 0.20 mass% and 0.4 mass% or less, preferably 0.25 to 0.35 mass%. If the Cu content is less than the above range, the effect of Cu becomes too small. If the Cu content exceeds the above range, the potential of the fin material is made noble, the sacrificial anode effect is lowered, the melting point is lowered, and local melting is likely to occur during brazing.
　本発明に係る熱交換器用アルミニウム合金フィン材は、Ｚｎを含有する。Ｚｎは、フィン材中の電位を卑にし、犠牲陽極効果を与える。本発明に係る熱交換器用アルミニウム合金フィン材のＺｎの含有量は、１．１質量％以上２．０質量％未満、好ましくは１．５～１．９質量％である。Ｚｎの含有量が、上記範囲未満だと、Ｚｎの効果が小さくなり過ぎる。また、Ｚｎの含有量が、上記範囲を超えると、粒界腐食感受性が高くなり、また、融点が低下して、ろう付け時に局部的な溶融が生じ易くなる。 The aluminum alloy fin material for heat exchanger according to the present invention contains Zn. Zn lowers the potential in the fin material and provides a sacrificial anode effect. The Zn content in the aluminum alloy fin material for a heat exchanger according to the present invention is 1.1 mass% or more and less than 2.0 mass%, preferably 1.5 to 1.9 mass%. If the Zn content is less than the above range, the effect of Zn becomes too small. Further, if the Zn content exceeds the above range, the intergranular corrosion sensitivity becomes high, the melting point is lowered, and local melting is likely to occur during brazing.
　本発明に係る熱交換器用アルミニウム合金フィン材は、更に、０．０５～０．３質量％のＺｒ、０．０５～０．３質量％のＣｒ及び０．０６～０．３５質量％のＴｉのうちの１種又は２種以上を含有することができる。 The aluminum alloy fin material for a heat exchanger according to the present invention further includes 0.05 to 0.3% by mass of Zr, 0.05 to 0.3% by mass of Cr, and 0.06 to 0.35% by mass of Ti. 1 type or 2 types or more can be contained.
　Ｚｒは、ろう付け後の結晶粒径を粗大化し、耐高温座屈性及びろう付け性を向上させる。Ｚｒの含有量が、０．０５質量％未満だと、Ｚｒの効果が無く、また、０．３質量％を超えると、粗大化合物を生じ、正常な板材の製造が困難になる。 Zr coarsens the grain size after brazing and improves high temperature buckling resistance and brazing. When the content of Zr is less than 0.05% by mass, there is no effect of Zr. When the content of Zr exceeds 0.3% by mass, a coarse compound is produced and it becomes difficult to produce a normal plate material.
　Ｃｒは、ろう付け後の結晶粒径を粗大化し、耐高温座屈性及びろう付け性を向上させる。Ｃｒの含有量が、０．０５質量％未満だと、Ｃｒの効果が無く、また、０．３質量％を超えると、粗大化合物を生じ、正常な板材の製造が困難になる。 Cr increases the crystal grain size after brazing and improves high temperature buckling resistance and brazing. When the Cr content is less than 0.05% by mass, there is no effect of Cr. When the Cr content exceeds 0.3% by mass, a coarse compound is produced, and it becomes difficult to produce a normal plate material.
　Ｔｉは、フィン材の板厚方向に濃度の高い領域と低い領域とに分かれ、それらが交互に分布する層状となり、フィン材の防食寿命を高める。Ｔｉの含有量が、０．０６質量％未満だと、Ｔｉの効果が無く、また、０．３５質量％を超えると、粗大化合物を生じ、正常な板材の製造が困難になる。 Ti is divided into a high-concentration region and a low region in the plate thickness direction of the fin material, and becomes a layered form in which they are alternately distributed, thereby increasing the corrosion-proof life of the fin material. When the Ti content is less than 0.06% by mass, there is no effect of Ti. When the Ti content exceeds 0.35% by mass, a coarse compound is produced, making it difficult to produce a normal plate material.
　本発明に係る熱交換器用アルミニウム合金フィン材は、更に、０．２質量％以下のＭｇを含有することができる。Ｍｇは、ろう付け前及びろう付け後のフィン材の強度を向上させる効果を有し、０．０５質量％未満ではその効果が小さいが、ろう付け性低下の観点から、含有量を０．２質量％以下に制限する。フッ化物系のフラックスを使用する不活性ガス雰囲気ろう付けの場合、Ｍｇの含有量が０．２質量％を超えると、Ｍｇがフッ化物系フラックスと反応してフィン材とのろう付け性が阻害され、また、Ｍｇのフッ化物が生成してろう付け部の外観が悪くなる。 The aluminum alloy fin material for a heat exchanger according to the present invention may further contain 0.2% by mass or less of Mg. Mg has the effect of improving the strength of the fin material before brazing and after brazing, and the effect is small at less than 0.05% by mass, but from the viewpoint of lowering brazing properties, the content is 0.2. Limited to mass% or less. In the case of brazing with an inert gas atmosphere using a fluoride-based flux, if the Mg content exceeds 0.2% by mass, the Mg reacts with the fluoride-based flux and inhibits brazing with the fin material. In addition, Mg fluoride is generated and the appearance of the brazed portion is deteriorated.
　本発明に係る熱交換器用アルミニウム合金フィン材のマトリックスは、再結晶組織である。本発明に係る熱交換器用アルミニウム合金フィン材のマトリックスが、再結晶組織であることにより、ろう付け後の結晶粒径が大きくなるため、粒界に沿ってろう材が浸透し難くなり、耐高温座屈性が向上する。一方、マトリックスが繊維組織の場合は、ろう付け後の結晶粒径が小さくなり、エロージョンの発生により耐高温座屈性が低くなる。本発明の熱交換器用アルミニウム合金フィン材を製造する方法であるが、鋳塊を均質化処理した後、熱間圧延、冷間圧延、中間焼鈍、冷間圧延を行い、所定の厚さの熱交換器用アルミニウム合金フィン材を得ることができる。均質化処理後はそのまま熱間圧延を行ってもよいし、いったん常温まで冷却し、再加熱して熱間圧延を行うこともできる。なお、鋳塊の均質化処理温度及び均質化処理時間、均質化処理後の冷却速度、熱間圧延開始温度及び熱間圧延終了温度、熱間圧延後の冷間圧延における加工度、中間焼鈍温度および中間焼鈍時間と中間焼鈍後の冷却速度、中間焼鈍後の冷間加工度等を、適宜選択することにより、フィン材のマトリックスを、再結晶組織とすることができる。ただし、フィン材のマトリックスを再結晶組織とするためには、熱間圧延に続く冷間圧延後のフィン材の再結晶完了温度より中間焼鈍温度を高くする必要がある。フィン材の再結晶完了温度は、フィン材の成分、均質化処理温度及び均質化処理時間、均質化処理後の冷却速度、熱間圧延開始温度及び熱間圧延終了温度、熱間圧延後の冷間圧延における加工度により変化するため、それに応じた中間焼鈍温度にする。 The matrix of the aluminum alloy fin material for heat exchanger according to the present invention has a recrystallized structure. Since the matrix of the aluminum alloy fin material for heat exchanger according to the present invention has a recrystallized structure, the crystal grain size after brazing becomes large, so that the brazing material hardly penetrates along the grain boundary, and is resistant to high temperatures. Buckling is improved. On the other hand, when the matrix is a fiber structure, the crystal grain size after brazing becomes smaller, and the high temperature buckling resistance is lowered due to the occurrence of erosion. This is a method for producing an aluminum alloy fin material for a heat exchanger according to the present invention. After the ingot is homogenized, hot rolling, cold rolling, intermediate annealing, and cold rolling are performed to obtain a heat having a predetermined thickness. An aluminum alloy fin material for an exchanger can be obtained. After the homogenization treatment, hot rolling may be performed as it is, or it may be cooled to room temperature and reheated for hot rolling. Ingot homogenization treatment temperature and homogenization treatment time, cooling rate after homogenization treatment, hot rolling start temperature and hot rolling end temperature, workability in cold rolling after hot rolling, intermediate annealing temperature And the matrix of a fin material can be made into a recrystallized structure by selecting suitably the intermediate annealing time, the cooling rate after intermediate annealing, the cold work degree after intermediate annealing, and the like. However, in order to make the matrix of the fin material a recrystallized structure, it is necessary to make the intermediate annealing temperature higher than the recrystallization completion temperature of the fin material after the cold rolling subsequent to the hot rolling. The recrystallization completion temperature of the fin material is the composition of the fin material, the homogenization treatment temperature and the homogenization treatment time, the cooling rate after the homogenization treatment, the hot rolling start temperature and the hot rolling end temperature, and the cooling after the hot rolling. Since it changes depending on the degree of processing in the hot rolling, the intermediate annealing temperature is set accordingly.
　フィン材の組織の判別であるが、結晶粒界が観察できるような研磨及びエッチング処理を行い、光学顕微鏡で観察することで、再結晶組織か繊維組織かどうかを判別することができる。結晶粒界が明瞭に観察でき、組織が繊維状に延ばされた圧延組織が観察されない場合は、再結晶組織であり、一方、結晶粒界が明瞭に観察されず、圧延組織が観察される場合は、繊維組織と判別される。再結晶組織と繊維組織が混在する場合もあるが、再結晶組織と繊維組織が混在する場合は、繊維組織領域でのろう付け後の結晶粒径が小さくなるため好ましくない。組織観察は中間焼鈍後に行うと判別しやすいが、中間焼鈍後の冷間圧延後でも判別することはできる。 As for the structure of the fin material, it is possible to determine whether the structure is a recrystallized structure or a fiber structure by performing polishing and etching processes so that crystal grain boundaries can be observed and observing with an optical microscope. When the grain boundary can be clearly observed and the rolled structure whose structure is extended to a fiber is not observed, it is a recrystallized structure, while the grain boundary is not clearly observed and the rolled structure is observed. In the case, it is discriminated as a fiber structure. In some cases, a recrystallized structure and a fiber structure are mixed, but a mixed recrystallized structure and a fiber structure is not preferable because the crystal grain size after brazing in the fiber structure region becomes small. Although it is easy to discriminate when the structure observation is performed after the intermediate annealing, it can be discriminated even after cold rolling after the intermediate annealing.
　本発明の熱交換器用アルミニウム合金フィン材を、チューブ材やプレート材など他の熱交換器を構成する部材と組み合わせ、ろう付け接合することにより熱交換器を製造することができる。チューブ材としては、芯材にろう材及び犠牲陽極材をクラッドしたブレージングシート条を、ろう材が外側、犠牲陽極材が内側になるように成形し、側端面を高周波溶接して円管とし、ロール成形により偏平なチューブ形状としたものが用いられる。また、チューブ材としては、板の端側の一部を重ね合わせたり、板の一部をチューブの内柱になるように折り曲げることにより、溶接することなく、ろう付け加熱により偏平チューブ形状としたものも用いられる。更には、押出偏平多穴チューブの外表面にＳｉ粉末などのろう材粉末を塗装し、フィン材とろう付け接合することもできる。ろう材粉末にはフラックス成分を有する粉末や犠牲陽極効果を有する粉末、バインダーを混合させることができる。プレート材としては、芯材に必要に応じてろう材や犠牲陽極材がクラッドされた板が用いられ、所望の形状に成形加工されて用いられる。 A heat exchanger can be manufactured by combining the aluminum alloy fin material for a heat exchanger of the present invention with a member constituting another heat exchanger such as a tube material or a plate material, and brazing and joining. As a tube material, a brazing sheet strip in which a brazing material and a sacrificial anode material are clad on a core material is molded so that the brazing material is on the outside and the sacrificial anode material is on the inside, and the side end face is high-frequency welded into a circular tube, A flat tube shape is used by roll forming. In addition, as a tube material, a part of the end side of the plate is overlapped, or a part of the plate is bent so as to become an inner column of the tube, so that a flat tube shape is formed by brazing without welding. Things are also used. Furthermore, a brazing filler metal powder such as Si powder can be coated on the outer surface of the extruded flat multi-hole tube and brazed to the fin material. The brazing powder can be mixed with a powder having a flux component, a powder having a sacrificial anode effect, and a binder. As the plate material, a plate in which a core material is clad with a brazing material or a sacrificial anode material is used as necessary, and is molded into a desired shape and used.
　上記チューブ材として用いられるブレージングシートの芯材は、熱交換器用として用いられるものであれば、特に限定されるものではないが、純Ａｌ、Ａｌ－Ｃｕ系合金、Ａｌ－Ｍｎ系合金、Ａｌ－Ｍｎ－Ｃｕ系合金、Ａｌ－Ｃｕ－Ｍｎ－Ｍｇ系合金等が挙げられる。 The core material of the brazing sheet used as the tube material is not particularly limited as long as it is used for a heat exchanger, but pure Al, Al—Cu alloy, Al—Mn alloy, Al— Examples thereof include Mn—Cu alloys and Al—Cu—Mn—Mg alloys.
　また、上記ろう材成分は、上記チューブ材やプレート材よりも低い融点を有していれば、いずれの合金を用いてもよく、例えば、Ａｌ－Ｓｉ系合金、Ａｌ－Ｓｉ－Ｚｎ系合金、Ａｌ－Ｓｉ－Ｃｕ系合金などのＳｉを含むアルミニウム合金粉末等、Ｋ２ＳｉＦ６などのＳｉを含有しろう付け時にろう材を生成するフラックス等が、挙げられる。 The brazing material component may be any alloy as long as it has a melting point lower than that of the tube material or plate material, such as an Al—Si alloy, an Al—Si—Zn alloy, Examples thereof include an aluminum alloy powder containing Si such as an Al—Si—Cu alloy, a flux that contains Si such as K 2 SiF 6 and generates a brazing material when brazing.
　ろう付け後の冷却速度であるが、５５０℃から４５０℃までの冷却速度を５０～８０℃／分とすることが好ましい。遅くなり過ぎるとＣｕ系析出物が粒界にそって析出しやすくなり、粒界腐食が生じ易くなる。 The cooling rate after brazing is preferably 50 to 80 ° C./min from 550 ° C. to 450 ° C. If it is too slow, Cu-based precipitates are likely to precipitate along the grain boundaries, and intergranular corrosion tends to occur.
　本発明の熱交換器用アルミニウム合金フィン材は、Ｃｕ含有量とＺｎ含有量が適正な範囲であり、且つ、フィン材のマトリックス組織が、再結晶組織であるので、ろう付け後の強度が高く且つ耐食性が高い。 The aluminum alloy fin material for a heat exchanger of the present invention has a Cu content and a Zn content in appropriate ranges, and the matrix structure of the fin material is a recrystallized structure, so that the strength after brazing is high and High corrosion resistance.
　連続鋳造によって、表１及び表２に示す組成の鋳魂を鋳造した。これらの合金を常法に従って均質化処理した後、熱間圧延、その後、冷間圧延、中間焼鈍及び仕上げ冷間圧延を経て厚さ０．０６ｍｍの板（Ｈ１４）を作製した。このとき、中間焼鈍温度及び冷間加工度の調整により、アルミニウム合金フィン材の組織を調整した。 Casting souls having the compositions shown in Tables 1 and 2 were cast by continuous casting. After homogenizing these alloys according to a conventional method, a plate (H14) having a thickness of 0.06 mm was manufactured through hot rolling, then cold rolling, intermediate annealing, and finish cold rolling. At this time, the structure of the aluminum alloy fin material was adjusted by adjusting the intermediate annealing temperature and the cold work degree.
　上記によって得られたアルミニウム合金フィン材について、以下の方法に従って、（１）組織、（２）融点を評価した。また、フィン材を窒素ガス中で、６０５℃に加熱した後、５５０℃から４５０℃まで６０℃／分の冷却速度で冷却し、得られた試験片について、(３)ろう付け後の引張強さ、（４）ろう付け性、（５）自己耐食性、（６）粒界腐食感受性を評価した。 The aluminum alloy fin material obtained as described above was evaluated for (1) structure and (2) melting point according to the following method. In addition, after heating the fin material to 605 ° C. in nitrogen gas, the fin material was cooled from 550 ° C. to 450 ° C. at a cooling rate of 60 ° C./min. For the obtained test piece, (3) Tensile strength after brazing (4) Brazeability, (5) Self-corrosion resistance, (6) Intergranular corrosion sensitivity was evaluated.
（１）組織状況
　Ｈ１４素材の表面を研磨した後エッチングし、ミクロ組織を顕微鏡で観察することにより、組織状況を観察した。結晶粒が判別できる場合は再結晶組織と判定し、結晶粒が明確に観察されず圧延組織が観察される場合は繊維状組織と判定した。
（２）融点
　Ｈ１４素材を示差熱分析によって固相線温度を測定した。昇温速度は１０℃／分とし、溶融するまで加熱した。
（３）ろう付け後の引張強さ
　ＪＩＳ５号試験片に成型した後、常温で引張試験を行い、引張強さを測定した。
（４）ろう付け性
　フィン材をコルゲート成形し、ＪＩＳ－Ａ３００３合金を心材とし、ＪＩＳ－Ａ４０４５合金をろう材とする厚さ０．２０ｍｍの板材を偏平形状に成形したチューブとを組付けて、チューブ材のろう材側表面に濃度３％のフッ化物系フラックスを塗布した後、窒素ガス雰囲気中６０５℃で３分間ろう付け加熱を行い、熱交換器のミニコアを作製した。このミニコアについて、フィン材とチューブ材との接合部を目視で観察して、フィンの座屈及び溶融の有無からろう付け性を評価した。座屈も溶融も無かった場合を○、座屈又は溶融が有った場合を×とした。
（５）耐食性
　ろう付け性の評価用ミニコアと同様に作製したミニコアについて、ＪＩＳ－Ｈ８６８１のキャス試験法に準拠した腐食試験を２週間行った。試験後のチューブのろう材側の腐食状況及びフィンの腐食状態を評価した。チューブに貫通孔が発生しなかったものを○、チューブに貫通孔が発生したものを×とした。また、フィンの自己腐食が少ないものを○、フィンの自己腐食が大きいものを×とした。また、ＩＳＯ／ＤＩＳ１１８４６に基づいて２時間浸漬試験を実施し、フィン断面のミクロ組織観察を行って、フィンの粒界腐食状況を調査した。粒界腐食が発生していないもの、あるいは軽微なものを○、粒界腐食が顕著なものを×とした。 (1) Organizational state The surface of the H14 material was polished and then etched, and the microstructure was observed by observing the microstructure with a microscope. When crystal grains could be discriminated, it was determined as a recrystallized structure, and when crystal grains were not clearly observed and a rolled structure was observed, it was determined as a fibrous structure.
(2) Melting point The solidus temperature of the H14 material was measured by differential thermal analysis. The heating rate was 10 ° C./min, and heating was performed until melting.
(3) Tensile strength after brazing After molding into a JIS No. 5 test piece, a tensile test was performed at room temperature to measure the tensile strength.
(4) Brazing property A corrugated fin material, a JIS-A3003 alloy core material and a JIS-A4045 alloy brazing material 0.20 mm thick plate material assembled into a flat shape, After applying a fluoride flux with a concentration of 3% to the brazing material side surface of the tube material, brazing heating was performed at 605 ° C. for 3 minutes in a nitrogen gas atmosphere to produce a mini-core of the heat exchanger. About this minicore, the joint part of a fin material and a tube material was observed visually, and brazing was evaluated from the presence or absence of the buckling of a fin and fusion | melting. The case where there was neither buckling nor melting was rated as ◯, and the case where there was buckling or melting was rated as x.
(5) Corrosion resistance A mini-core produced in the same manner as the mini-core for brazing evaluation was subjected to a corrosion test based on the JIS-H8681 cast test method for two weeks. The corrosion situation of the brazing material side of the tube after the test and the corrosion condition of the fin were evaluated. A sample in which no through-hole was generated in the tube was indicated by ◯, and a sample in which a through-hole was generated in the tube was indicated by ×. In addition, the case where the self-corrosion of the fin is small is marked with ◯, and the case where the self-corrosion of the fin is large is marked with x. Further, a 2-hour immersion test was performed based on ISO / DIS11846, and the microstructure of the fin cross section was observed to investigate the intergranular corrosion of the fin. The case where the intergranular corrosion did not occur or the case where the intergranular corrosion was slight was marked with ◯, and the case where the intergranular corrosion was remarkable was marked with X.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000003
 ＊Ｒ：再結晶組織、Ｆ：繊維状組織
Figure JPOXMLDOC01-appb-T000003
 * R: Recrystallized structure, F: Fibrous structure
Figure JPOXMLDOC01-appb-T000004
 ＊Ｒ：再結晶組織、Ｆ：繊維状組織
Figure JPOXMLDOC01-appb-T000004
 * R: Recrystallized structure, F: Fibrous structure
　表３に示すように、本条件を満たすＮｏ．１～２６、４２はいずれも、６０５℃の高温加熱時でもフィン溶融、座屈は認められずろう付け性は良好であった。ろう付け後の引張強さはいずれも１５５ＭＰａ以上の優れた強度を示した。また耐食性においてもＣＡＳＳ試験でチューブ材に貫通は発生しておらず、フィン材の犠牲陽極効果が作用していることを示した。またＩＳＯ－Ｂ法においても粒界腐食は発生せず、粒界腐食感受性が低いことを示した。 As shown in Table 3, No. satisfying this condition. In all of Nos. 1 to 26 and 42, fin melting and buckling were not observed even when heated at a high temperature of 605 ° C., and the brazing property was good. The tensile strength after brazing showed an excellent strength of 155 MPa or more. Further, in terms of corrosion resistance, no penetration occurred in the tube material in the CASS test, indicating that the sacrificial anode effect of the fin material is acting. Also, ISO-B method showed no intergranular corrosion and low intergranular corrosion sensitivity.
　これに対し、Ｎｏ．２７は素材が繊維状組織のため、ろう付け時の加熱によって座屈が生じた。Ｎｏ．２８はＳｉの含有量が多過ぎるため、ろう付け時の加熱によって局部溶融が生じた。Ｎｏ．２９はＳｉの含有量が少な過ぎるため、引張強度が十分でない。Ｎｏ．３０はＦｅの含有量が多過ぎるため、自己腐食が大きくフィンの自己消耗が顕著となり、犠牲陽極効果が持続できなかった。Ｎｏ．３１はＦｅの含有量が少な過ぎるため、引張強度が十分でない。Ｎｏ．３２はＣｕの含有量が多過ぎるため、ろう付け時の加熱によって局部溶融が生じた。Ｎｏ．３３はＣｕの含有量が少な過ぎるため、引張強度が十分でない。Ｎｏ．３４はＭｎの含有量が多過ぎるため、熱間圧延が困難であり。健全な材料が製造できなかった。Ｎｏ．３５はＭｎの含有量が少な過ぎるため、引張強度が十分でない。Ｎｏ．３６はＺｎの含有量が多過ぎるため、粒界腐食が発生した。Ｎｏ．３７はＺｎの含有量が少な過ぎるため、犠牲陽極効果が劣り、ＣＡＳＳ試験でチューブ材に貫通孔が発生した。Ｎｏ．３８、３９はＣｒ、Ｚｒの含有量が多過ぎるため、熱間圧延が困難であり。健全な材料が製造できなかった。Ｎｏ．４０、Ｔｉの含有量が多過ぎるため、熱間圧延が困難であり。健全な材料が製造できなかった。Ｎｏ．４１はＭｇの含有量が多過ぎるため、ろう付け接合されなかった。 On the other hand, No. Since the material of No. 27 was a fibrous structure, buckling occurred by heating during brazing. No. Since 28 contained too much Si, local melting occurred by heating during brazing. No. 29 has too little Si content, so the tensile strength is not sufficient. No. Since No. 30 contained too much Fe, self-corrosion was large, and self-consumption of the fins became remarkable, and the sacrificial anode effect could not be sustained. No. No. 31 has too little Fe content, so the tensile strength is not sufficient. No. Since No. 32 contained too much Cu, local melting occurred by heating during brazing. No. Since 33 has too little Cu content, the tensile strength is not sufficient. No. Since 34 has too much Mn content, hot rolling is difficult. Sound material could not be manufactured. No. 35 has too little Mn content, so the tensile strength is not sufficient. No. Since No. 36 contained too much Zn, intergranular corrosion occurred. No. No. 37 had too little Zn content, so the sacrificial anode effect was inferior, and through holes were generated in the tube material in the CASS test. No. Since 38 and 39 contain too much Cr and Zr, hot rolling is difficult. Sound material could not be manufactured. No. 40, because the Ti content is too high, hot rolling is difficult. Sound material could not be manufactured. No. No. 41 was not brazed because the Mg content was too high.

Claims (3)

  1. 　１．０～２．０質量％のＭｎ、０．５～１．３質量％のＳｉ、０．１～０．８質量％のＦｅ、０．２０質量％超え０．４質量％以下のＣｕ、１．１質量％以上２．０質量％未満のＺｎを含有し、残部がＡｌ及び不可避不純物からなるアルミニウム合金フィン材であり、アルミニウム合金フィン材のマトリックスが再結晶組織であることを特徴とするろう付け後の強度と耐食性に優れた熱交換器用アルミニウム合金フィン材。 1.0 to 2.0% by mass of Mn, 0.5 to 1.3% by mass of Si, 0.1 to 0.8% by mass of Fe, 0.20% by mass to 0.4% by mass or less of Cu 1.1% by mass or more and less than 2.0% by mass of Zn, the balance being an aluminum alloy fin material made of Al and inevitable impurities, and the matrix of the aluminum alloy fin material having a recrystallized structure, Aluminum alloy fin material for heat exchangers with excellent strength and corrosion resistance after brazing.
  2. 　前記熱交換器用アルミニウム合金フィン材が、更に、０．０５～０．３質量％のＺｒ、０．０５～０．３質量％のＣｒ及び０．０６～０．３５質量％のＴｉのうちの１種又は２種以上を含有することを特徴とする請求項１記載のろう付け後の強度と耐食性に優れた熱交換器用アルミニウム合金フィン材。 The aluminum alloy fin material for heat exchanger further comprises 0.05 to 0.3% by mass of Zr, 0.05 to 0.3% by mass of Cr, and 0.06 to 0.35% by mass of Ti. The aluminum alloy fin material for heat exchangers having excellent strength and corrosion resistance after brazing according to claim 1, wherein the fin alloy contains one or more kinds.
  3. 　前記熱交換器用アルミニウム合金フィン材が、更に、０．０５～０．２質量％のＭｇを含有することを特徴とする請求項１又は２いずれか１項記載のろう付け後の強度と耐食性に優れた熱交換器用アルミニウム合金フィン材。 3. The strength and corrosion resistance after brazing according to claim 1, wherein the aluminum alloy fin material for heat exchanger further contains 0.05 to 0.2% by mass of Mg. Excellent aluminum alloy fin material for heat exchanger.
PCT/JP2012/069962 2011-08-12 2012-08-06 Aluminum alloy fin material for heat exchanger offering excellent post-brazing strength and corrosion resistance WO2013024732A1 (en)

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