JP3876505B2 - Al alloy fin material for heat exchangers with excellent erosion resistance - Google Patents

Description

【００１８】
【表２】

【００１９】
【表３】

【００２０】
【表４】

【００２１】
これら鋳塊Ａ〜ｋを５００℃で熱間圧延した後、表５〜表８に示される条件の中間焼鈍および通常の冷間圧延を繰り返し施し、最終冷間圧延を表５〜表８に示される圧延率にて厚さ：１００μｍの冷延板とすることにより本発明フィン材１〜３７、比較フィン材１〜２および従来フィン材をそれぞれ製造し、得られた本発明フィン材１〜３７、比較フィン材１〜２および従来フィン材の平均結晶粒径およびＬＴ／Ｌを測定し、その結果を表５〜表８に示した。
【００２２】
一方、心材としてＡｌ−１重量％Ｍｎ−０．１５重量％Ｃｕ（ＡＡ３００３）を用意し、さらにろう材としてＡｌ−７．５重量％Ｓｉ（ＡＡ４３４３）を用意し、心材：ろう材＝８５：１５のクラッド率となるように心材の片面にろう材をクラッドした厚さ：０．３ｍｍのブレージングシートを用意した。このブレージングシートの片面にコルゲート加工を施した本発明フィン材１〜３７、比較フィン材１〜２および従来フィン材を組み付け、これにフラックスを塗布した後、６００℃のＡｒ雰囲気中でろう付けしたのち空冷し、その後断面の観察を行うことにより、ろうによるフィンの最大エロージョン深さ（図１のエロージョン部４の厚さＨ）について測定し、その結果を表５〜表８に示した。
【００２３】
【表５】

【００２４】
【表６】

【００２５】
【表７】

【００２６】
【表８】

【００２７】
【発明の効果】
表１〜表８に示される結果から、本発明フィン材１〜３７は従来フィン材と比べて、溶融ろうによるフィンの最大エロージョン深さが小さいところから、本発明フィン材１〜３７は、いずれも一段と耐エロージョン性に優れていることが明らかである。
一方、比較Ａｌ合金フィン材１〜２に見られるように、Ａｌ合金の平均結晶粒径およびＬＴ／Ｌのずれかがこの発明の範囲から外れると（この発明の範囲から外れた値を表７に＊印を付して示した）、最大エロージョン深さが大きくなり過ぎることが明らかである。
【００２８】
上述のように、この発明の熱交換器用Ａｌ合金フィン材は、耐エロージョン性に優れ、この発明のフィン材で作製したＡｌ熱交換器は軽量化および小型化が可能であると共に、熱交換機能の一層の向上に役立つものである。
【図面の簡単な説明】
【図１】 フィン材を冷媒通路形成体にろう付けして得られた接合部の一部拡大断面図である。
【図２】 フィン材を冷媒通路形成体にろう付けして得られた接合部の一部拡大断面図である。
【符号の説明】
１ フィン材、
２ 冷媒通路形成体、
３ フィレット、
４ エロージョン部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an Al alloy fin material for a heat exchanger having excellent erosion resistance.
[0002]
[Prior art]
Conventionally, a fin material, which is a structural member of a heat exchanger that is generally used as a radiator of an automobile, is brazed to a refrigerant passage forming body (for example, a pipe material) and is metallically bonded to widen a heat transfer area. Thus, the heat exchange efficiency is improved. As these fin materials, AA1050 alloy, AA3003 alloy and the like are usually used, but in recent years, Al alloy fin materials for heat exchangers having the following high strength have been developed.
Fe: 1.1 to 1.5% by weight, Si: 0.35 to 0.8% by weight, Mn: 0.15 to 0.4% by weight, with the remainder consisting of Al and inevitable impurities Al alloy fin material for heat exchanger having high strength (see JP-A-1-292945),
Fe: 1.1 to 1.5 wt%, Si: 0.1 to 0.8 wt%, Mg: 0.05 to 0.5 wt%, and Mn: 0.1 to 0.8 wt% %, Zr: Al alloy fin material for heat exchangers having a high strength having a composition comprising Al and inevitable impurities, containing one or two of 0.02 to 0.2% by weight 1-292955 gazette),
Fe: 1.1 to 1.5% by weight, Si: 0.35 to 0.8% by weight, Zr: 0.02 to 0.2% by weight, with the remainder consisting of Al and inevitable impurities Al alloy fin material for heat exchangers having high strength (see Japanese Patent Laid-Open No. 1-292953).
[0003]
Since these fin materials have high strength, they can be made thinner than conventional fin materials. Therefore, the weight reduction and size reduction of the Al heat exchanger are promoted, and further, the vacuum brazing is performed when the heat exchanger is assembled. It does not cause deformation during mounting or practical use, and has excellent thermal conductivity, so it greatly contributes to improving the heat exchange function compared to the past. In order to braze the fin material to the refrigerant passage forming body, as shown in the partially enlarged cross-sectional view of FIG. The gap between the material and the refrigerant passage forming body is filled with molten solder to form the fillet 3, and the fin material 1 and the refrigerant passage forming body 2 are firmly joined by the fillet 3. In this case, the fact that a part of the fin material 1 and the refrigerant passage forming body 2 is melted by the melting wax is called erosion (erosion), and the eroded part is called the erosion part 4. The presence of the erosion portion 4 having an appropriate thickness greatly contributes to the strong bonding between the fin material and the coolant passage forming body.
[0004]
[Problems to be solved by the invention]
In recent years, in order to improve the fuel efficiency of automobiles, etc., heat exchangers, which are one of the automotive parts, are required to be lighter and more compact, and the heat exchanger fin materials are becoming thinner and more heat exchangers. The reduction in weight and size is promoted. However, the conventional fin material is easily eroded by the molten solder, and when the thin fin material that is easily eroded (eroded) is brazed to the refrigerant passage forming body, the fin material is thin, so that FIG. As shown in the enlarged cross-sectional view, the erosion portion 4 is larger than the thickness of the fin material 1, and the thickness t of the fin material 1 in contact with the fillet 3 is extremely thin. In the worst case, erosion The part 4 penetrates the fin material 1, so that not only the pressure strength and structure necessary for the fin material of the heat exchanger cannot be maintained, but also a problem in that the heat exchange function is unavoidably deteriorated.
[0005]
[Means for Solving the Problems]
Therefore, as a result of conducting research to obtain a fin material excellent in erosion resistance from the above viewpoint,
(A) The erosion of the fin material occurs at the inside of the crystal grains and at the grain boundaries, but the damage caused by the erosion is predominantly the one that proceeds at the crystal grain boundaries of the fin material. When the crystal grains are enlarged to reduce the proportion of the grain boundary in the structure, and the average grain size of the crystal grains in the plane perpendicular to the thickness direction of the fin material is 300 to 50,000 μm, more excellent erosion resistance is exhibited. ,
(B) In general, the fin material of the heat exchanger is finished by cold rolling an Al alloy, but the better the erosion resistance the closer the crystal grain structure obtained by cold rolling is to a circular shape. The length of crystal grains in the rolling direction of the fin material is denoted by L, and the length of crystal grains in the direction perpendicular to the rolling direction and parallel to the rolling surface is denoted by LT, and the ratio of L to LT (hereinafter referred to as LT / L) is preferably 0.12 to 1,
(C) The average grain size of the crystal grains in the plane perpendicular to the thickness direction of the fin material is increased so as to be 300 to 50,000 μm to reduce the proportion of crystal grain boundaries, and the crystal grain shape is close to a circle. The Al alloy constituting the fin material of the heat exchanger having LT / L in the range of 0.12 to 1 may be any structural Al alloy, but Fe: 1 having a higher Fe content than conventional ones. As a result, research results have been obtained, such as better erosion resistance when the Al alloy contains more than .5 wt% to 3 wt%.
[0006]
And it is preferable that the Al alloy constituting the Al alloy fin material for heat exchangers with excellent erosion resistance of the present invention is composed of an Al alloy containing more than 1.5% by weight of Fe. As an Al alloy containing more than 1.5% by weight,
(A) Fe: Al alloy containing more than 1.5 to 3% by weight, with the remainder comprising Al and inevitable impurities,
(B) Fe: more than 1.5 to 3% by weight, Mn: 0.1 to 0.5% by weight, Si: 0.1 to 0.5% by weight, Cu: 0.05 to 0. An Al alloy containing one or more of 7% by weight, the balance being composed of Al and inevitable impurities,
(C) Fe: more than 1.5 to 3% by weight, Zn: 0.5 to 3% by weight, Zr: 0.05 to 0.2% by weight, with the remainder consisting of Al and inevitable impurities Al alloy,
(D) Fe: more than 1.5 to 3 wt%, Zn: 0.5 to 3 wt%, Zr: 0.05 to 0.2 wt%, and Mn: 0.1 to 0.5 wt% %, Si: 0.1 to 0.5% by weight, Cu: 0.05 to 0.7% by weight, one or more of Al, and the remainder is Al having a composition composed of Al and inevitable impurities alloy,
(E) Al alloy having a composition in which Mg: 0.05 to 0.2% by weight is further added to the Al alloy described in (a), (b), (c) or (d). .
[0007]
Therefore, the present invention
(1) Fe: more than 1.5 to 3% by weight, with the balance being composed of Al and inevitable impurities, and the average grain size of the crystal grains in the plane perpendicular to the thickness direction of the fin material is 300 Al alloy fin material for heat exchangers having excellent erosion resistance, which is made of an Al alloy having crystal grains having a crystal grain size of 50,000 to 50,000 μm and LT / L of 0.12 to 1,
(2) Fe: more than 1.5 to 3% by weight, Mn: 0.1 to 0.5% by weight, Si: 0.1 to 0.5% by weight, Cu: 0.05 to 0. One or more of 7% by weight, the remainder having a composition composed of Al and inevitable impurities, and the average grain size of the crystal grains in the plane perpendicular to the thickness direction of the fin material is 300 to An Al alloy fin material for heat exchangers having excellent erosion resistance, which is made of an Al alloy having crystal grains of 50000 μm and LT / L of 0.12 to 1,
(3) Fe: more than 1.5 to 3% by weight, Zn: 0.5 to 3% by weight, Zr: 0.05 to 0.2% by weight, with the remainder consisting of Al and inevitable impurities Furthermore, the average grain size of the crystal grains in the plane perpendicular to the thickness direction of the fin material is 300 to 50000 μm, and LT / L is made of an Al alloy having crystal grains of 0.12 to 1. Al alloy fin material for heat exchangers with excellent erosion resistance,
(4) Fe: more than 1.5 to 3 wt%, Zn: 0.5 to 3 wt%, Zr: 0.05 to 0.2 wt%, and Mn: 0.1 to 0.5 wt% %, Si: 0.1 to 0.5% by weight, Cu: 0.05 to 0.7% by weight, one or more of them, and the balance is composed of Al and inevitable impurities Furthermore, the average grain size of the crystal grains in the plane perpendicular to the thickness direction of the fin material is 300 to 50000 μm, and LT / L is made of an Al alloy having crystal grains of 0.12 to 1. Al alloy fin material for heat exchangers with excellent erosion properties,
(5) The Al alloy according to (1), (2), (3) or (4) has a composition further containing Mg: 0.05 to 0.2% by weight; Excellent erosion resistance composed of an Al alloy having crystal grains having an average grain size of 300 to 50,000 μm in the plane perpendicular to the thickness direction and LT / L of 0.12 to 1 It is characterized by the Al alloy fin material for heat exchangers.
[0008]
In order to produce an Al alloy fin material for a heat exchanger excellent in erosion resistance according to the present invention, a billet obtained by semi-continuous casting is hot-rolled, and after intermediate annealing and cold rolling are repeated, the final cold In the rolling process, the intermediate annealing immediately before the final cold rolling is subjected to intermediate annealing for a longer time than before or after the intermediate annealing at a higher temperature than before, followed by the final cold rolling at a lower rolling rate than before. Can be manufactured. For example, the Al alloy fin material for heat exchangers with excellent erosion resistance according to the present invention is manufactured for an Al alloy that is conventionally subjected to intermediate annealing immediately before final cold rolling at 350 to 400 ° C. for 2 hours. The intermediate annealing immediately before the final cold rolling is carried out under the conditions of holding at 350 to 400 ° C. for 4 hours, holding over 400 to 500 ° C. for 3 hours, or holding over 500 to 600 ° C. for 2 hours, followed by final cooling The rolling rate of the final cold rolling of the present invention is 5 to 25% with respect to the conventional rolling rate of 30 to 80%.
[0009]
The average grain size and LT / L of the Al alloy crystal grains constituting the fin material, and the composition range of the Al alloy containing Fe exceeding 1.5% by weight is limited as described above. Explain why.
[0010]
(A) Fe
The Fe component is finely and uniformly dispersed in the base material after brazing to improve the strength of the fin material, and erosion due to brazing is advanced from within the crystal grains to improve erosion resistance, and the solid solubility after brazing is increased. Although it is small and has the effect of not causing a decrease in thermal conductivity even when dissolved in a substrate, its content is insufficient in strength when its content is 1.5% by weight or less, so it has a high thermal conductivity excellent in erosion resistance. On the other hand, if the content exceeds 3% by weight, the self-corrosion resistance is lowered and coarse crystals are easily formed, and the erosion resistance and strength are reduced. The content was determined to be more than 1.5 to 3% by weight. A more preferable range of the Fe content is 1.7 to 2.5% by weight.
[0011]
(B) Zn
The Zn component has an action of solid-dissolving in the base material to make the fin material electrochemically base and improve the sacrificial anode effect on the refrigerant passage forming body (for example, pipe material), but its content is 0.5 weight. If the content is less than 1%, the desired effect cannot be obtained. On the other hand, if the content exceeds 3% by weight, the solid solubility after brazing increases, the thermal conductivity decreases, and the self-corrosion resistance decreases. Therefore, the content was determined to be 0.5 to 3% by weight. A more preferable range of the Zn content is 0.8 to 2.0% by weight.
[0012]
(C) Zr
The Zr component forms a fine Al-Zr intermetallic compound after brazing and disperses it in the substrate, improving the strength and improving the erosion resistance. Even if it dissolves in the substrate, the thermal conductivity decreases. However, if the content is less than 0.05% by weight, the desired strength improvement effect cannot be obtained. On the other hand, if the content exceeds 0.2% by weight, hot workability and cold workability are reduced. Since it comes to deteriorate, the content was determined to be 0.05 to 0.2% by weight. A more preferable range of the Zr content is 0.08 to 0.15% by weight.
[0013]
(D) Mn, Si and Cu
These components are dispersed in the substrate as Al-Mn-Fe compound, Al-Si-Fe compound, and Al-Fe compound together with Al and Fe, so that the corrosion resistance and the thermal conductivity are not lowered, and Cu is further added to the substrate. It is added as necessary because it has the effect of significantly improving the strength of the fin material by solid solution, but its content is Mn: less than 0.1% by weight and Si: less than 0.2% by weight and Cu: 0 If it is less than 0.05% by weight, the desired strength improving effect cannot be obtained. On the other hand, if the content is Mn, if it exceeds 0.5% by weight, the thermal conductivity is remarkably lowered and the workability is also lowered. In the case of Si and Cu, when the content exceeds 0.5% by weight, the thermal conductivity and the erosion resistance during brazing are lowered. Wt%, Si 0.1 to 0.5 wt%, Cu: 0.05 to 0.7 was defined as wt%.
[0014]
(E) Mg
Since the Mg component has the effect of improving the strength by solid solution in the substrate, it is contained as necessary, but if the content is less than 0.05% by weight, the desired strength improvement effect cannot be obtained, On the other hand, if the content exceeds 0.2% by weight, the proportion of solid solution in the substrate increases, and there is a tendency to become electrochemically noble, the sacrificial anode effect on the pipe material is reduced, and brazing properties are impaired. At the same time, the erosion resistance and thermal conductivity during brazing are also lowered, so the content was determined to be 0.05 to 0.2% by weight.
[0015]
(F) Average grain size and shape of crystal grains In order for the fin material to have excellent erosion resistance, the crystal grain of the grain boundary is reduced by enlarging the crystal grains of the Al alloy constituting the fin material. In addition, it is necessary to further reduce the distortion of the crystal grains. For this purpose, the average grain size of the Al alloy grains constituting the fin material needs to be 300 μm or more, but it is difficult to increase the grain size beyond 50000 μm. In order to make the diameter 300 to 50,000 μm and further reduce distortion of the crystal grains due to the final cold rolling, the rolling rate of the final cold rolling should be made smaller than before to make the crystal grains nearly circular. From a preferable point, the value of LT / L needs to be 0.12 or more. Therefore, LT / L is set to 0.12 to 1. A more preferable range of the average grain size of Al alloy crystal grains constituting the fin material is 500 to 20000 μm, and a more preferable range of LT / L is 0.3 to 0.8.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Next, the Al alloy fin material of the present invention will be specifically described with reference to examples.
Ingots A to k were produced by preparing Al alloy melts having the component compositions shown in Tables 1 to 4 by a normal melting method, and casting the Al alloy melts by a semi-continuous casting method.
[0017]
[Table 1]

[0018]
[Table 2]

[0019]
[Table 3]

[0020]
[Table 4]

[0021]
After these ingots A to k are hot-rolled at 500 ° C., intermediate annealing and normal cold rolling under the conditions shown in Tables 5 to 8 are repeated, and the final cold rolling is shown in Tables 5 to 8. The present invention fin materials 1 to 37, the comparative fin materials 1 and 2, and the conventional fin materials 1 to 37 are obtained by forming a cold-rolled sheet having a thickness of 100 μm at a rolling ratio to be obtained, and the obtained fin materials 1 to 37 of the present invention. The average crystal grain size and LT / L of the comparative fin materials 1 and 2 and the conventional fin material were measured, and the results are shown in Tables 5 to 8.
[0022]
On the other hand, Al-1 wt% Mn-0.15 wt% Cu (AA3003) is prepared as the core material, and Al-7.5 wt% Si (AA4343) is prepared as the brazing material, and the core material: brazing material = 85: A brazing sheet having a thickness of 0.3 mm in which a brazing material was clad on one side of the core material so as to have a cladding rate of 15 was prepared. The present invention fin materials 1 to 37, comparative fin materials 1 and 2 and a conventional fin material that have been corrugated on one side of the brazing sheet are assembled, and flux is applied thereto, followed by brazing in an Ar atmosphere at 600 ° C. Thereafter, air cooling was performed, and then the cross-section was observed to measure the maximum erosion depth of the fin by the brazing (the thickness H of the erosion part 4 in FIG. 1). The results are shown in Tables 5 to 8.
[0023]
[Table 5]

[0024]
[Table 6]

[0025]
[Table 7]

[0026]
[Table 8]

[0027]
【The invention's effect】
From the results shown in Tables 1 to 8, the fin materials 1 to 37 of the present invention are smaller in the maximum erosion depth of the fin due to the fusion brazing than the conventional fin materials, It is clear that it is further excellent in erosion resistance.
On the other hand, as seen in the comparative Al alloy fin materials 1 and 2, when the deviation of the average crystal grain size and LT / L of the Al alloy is out of the scope of the present invention (Table 7 shows the values out of the scope of the present invention. It is clear that the maximum erosion depth becomes too large.
[0028]
As described above, the Al alloy fin material for heat exchanger of the present invention has excellent erosion resistance, and the Al heat exchanger made of the fin material of the present invention can be reduced in weight and size, and has a heat exchange function. It will help to further improve
[Brief description of the drawings]
FIG. 1 is a partially enlarged cross-sectional view of a joint obtained by brazing a fin material to a refrigerant passage forming body.
FIG. 2 is a partially enlarged cross-sectional view of a joint obtained by brazing a fin material to a refrigerant passage forming body.
[Explanation of symbols]
1 Fin material,
2 refrigerant passage forming body,
3 Fillets,
4 Erosion Club

Claims (5)

Fe: more than 1.5 to 3%, the balance is composed of Al and inevitable impurities, and the average grain size of the crystal grains in the plane perpendicular to the thickness direction of the fin material is 300 to 50,000 μm. When the length of crystal grains in the rolling direction of the fin material is indicated by L and the length of crystal grains in the direction perpendicular to the rolling direction and parallel to the rolling surface is indicated by LT, LT / L is 0.12 to 1. An Al alloy fin material for heat exchangers having excellent erosion resistance, wherein the Al alloy fin material is composed of an Al alloy composed of crystal grains. Fe: more than 1.5 to 3%,
further,
Mn: 0.1 to 0.5%
Si: 0.1 to 0.5%,
Cu: 0.05 to 0.7%,
1 or 2 or more of them, the remainder has a composition composed of Al and inevitable impurities, and the average grain size of the crystal grains in the plane perpendicular to the thickness direction of the fin material is 300 to 50000 μm. When the length of crystal grains in the rolling direction of the fin material is indicated by L and the length of crystal grains in the direction perpendicular to the rolling direction and parallel to the rolling surface is indicated by LT, LT / L is 0.12 to 1. An Al alloy fin material for heat exchangers having excellent erosion resistance, wherein the Al alloy fin material is composed of an Al alloy composed of crystal grains. Fe: more than 1.5 to 3%,
Zn: 0.5-3%,
Zr: 0.05 to 0.2%, the remainder is composed of Al and inevitable impurities, and the average grain size of the crystal grains in the plane perpendicular to the thickness direction of the fin material is 300 to 50,000 μm. When the length of the crystal grain in the rolling direction of the fin material is indicated by L, and the length of the crystal grain in the direction perpendicular to the rolling direction and parallel to the rolling surface is indicated by LT, LT / L is 0.12. An Al alloy fin material for heat exchangers excellent in erosion resistance, characterized by being composed of an Al alloy comprising crystal grains of ˜1. Fe: more than 1.5 to 3%,
Zn: 0.5-3%,
Zr: 0.05 to 0.2%,
In addition,
Mn: 0.1 to 0.5%
Si: 0.1 to 0.5%,
Cu: 0.05 to 0.7%,
Containing one or more of
The balance is composed of Al and inevitable impurities, and the average grain size of the crystal grains in the plane perpendicular to the thickness direction of the fin material is 300 to 50,000 μm, and the crystal grains in the rolling direction of the fin material When the length of the crystal grain in the direction perpendicular to the rolling direction and parallel to the rolling surface is indicated by LT, the length is L, and the LT / L is made of an Al alloy made of crystal grains having a ratio of 0.12 to 1. An Al alloy fin material for heat exchangers with excellent erosion resistance, characterized by   The Al alloy constituting the fin material is an Al alloy having a composition in which Mg: 0.05 to 0.2% is further added to the Al alloy according to claim 1, 2, 3 or 4. Al alloy fin material for heat exchangers with excellent erosion resistance.

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