JPH01255639A - Fin material for heat exchanger made of aluminum - Google Patents

Abstract

PURPOSE:To improve the heat conductivity, high temp. strength at the time of brazing and sagging resistance by regulating the core to a pure Al having specific value or below of Fe and Si content and regulating the surface material to an Al alloy having specific Mn content. CONSTITUTION:In the fin material for a heat exchanger made of Al, the alloy constituted of, by weight, 0.3-2.0% Mn and the balance consisting of Al is clad as the surface material to both sides or one side of the alloy as the core constituted of <=0.25% Fe, <=0.20% Si and the balance consisting of Al. In the above core, by the limitation of Fe content, heat conductivity and sagging resistance are improved and, by the limitation of Si content, heat conductivity is improved. The above surface material has excellent high temp. strength and, by the limitation of Mn content, has improved sagging resistance; but in the case of below the lower limit, it is ineffective, and in the case of above the upper limit, the effect is saturated and the heat conductivity is reduced. If required, each limiting amount of Zr, Cr and Ti or Zn, Sn In, etc., may be added to the above core and surface material.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a fin material for an aluminum heat exchanger.
In addition, the thermal conductivity of the fins has been improved.

・ [Prior art] Aluminum heat exchangers, such as automobile radiators and condensers, have fins made of bare material of Al or Al alloy, and Al-Si alloy brazing filler metal or Al-Al on both or one side of the fins. A fin made of a plating sheet clad with a Si-based alloy brazing material is used, and the fins are joined by a flux brazing method or a vacuum brazing method.

In other words, as shown in Figure 2, the radiator is a combination of a flat erw tube (2) made of a plating sheet clad with brazing material on the outside and bare corrugated fins (1), which are joined using the brazing method. . JIS for fin material
3003 alloy or an alloy to which Zn, Sn, In, etc. are added, JIS 3203 alloy, or JIS 6951 alloy is used, and the thickness thereof is 0.08 to 0.15 m. In the figure, (3) indicates the header, and (4) indicates the tank.

As shown in Figure 3, a serpentine type condenser is an extruded multi-hole tube (5) that is bender-processed into a serpentine shape.
It is combined with a fin (1) made of a corrugated plating sheet and joined by the wax bone method. The fin material is JIS 3003 alloy or Zn, Sn.
, In, etc. are added as a core material, and both sides of the alloy are coated with Al-
A plating sheet clad with 10 to 15% of Si-based alloy brazing material or Al-5r-My-based alloy brazing material is used, and its thickness is generally 0.16 m.

In addition, by adding Zn, Sn, In, etc. to the fin material, the potential can be roughly matched to the fin material.
It is known that the sacrificial effect of the fins becomes effective if the voltage is less than mV.

(Problem to be solved by the invention) HI3 material is usually used as the fin material to withstand the tightening of jigs during core assembly, but it has excellent high-temperature strength and sag resistance in brazing heat at around 600°C. If both properties are not sufficient, the brazing between each member and the fin will be incomplete due to deformation of the fins, causing problems such as deformation of the core, reduction in the strength of the core structure, and reduction in heat exchange performance.

In addition, when comparing the thermal conductivity of aluminum, pure Al shows 60%lAC3 in terms of electrical conductivity, but in the l-Mn-based JIS 3003 alloy used for fin materials, the solid solution of Mn and Sl in the solder joint As a result, the conductivity decreases to 40%lAC3 or less, and the heat exchange performance of the fins decreases. Also $I
T! Al fin materials may not have sufficient high-temperature strength or 1° nog resistance, and brazing may not be successful.

(Means for Solving the Problems) In view of this, as a result of various studies, the present invention has high thermal conductivity,
We have developed a fin material for aluminum heat exchangers that has excellent high-temperature strength and league resistance during brazing.

That is, the present invention provides F e of 0.25 wt% or less (hereinafter wt
% is abbreviated as %), contains 0.20% or less of Si, and the balance is Al.
The core material is an alloy consisting of and unavoidable impurities, and the core material is clad with an alloy containing 0.3 to 2.0% Mn on both or one side, and the remainder is Af and unavoidable impurities as the skin material. .

The above core material contains 0.25% or less of Fe and 0.20% of Si.
Contains and further includes: Zr 0.3% or less, Cr 0.3% or less, Ti 0.3% or less, Mrl less than 0.3% lMg0.
3% or less, Cu 0.3% or less, Sn 0.1% or less.

It is possible to use an alloy containing one or more of In 0.1% or less, Znz, o% or less, and Ca 0.4% or less, with the remainder being Al and inevitable impurities.

In addition, the skin material contains 0.3 to 2.0% Mn, and further contains Zn.
2.0% or less, Sn 0.1% or less, In 0.1% or less,
Zr 0.3% or less, Cr 0.3% or less.

It is possible to use an alloy containing at least one of Cu 0.3% or less, Mg 0.3% or less, Li 0.3% or less, and Ca 0.4% or less, with the remainder being Al and inevitable impurities.

Furthermore, A, f! -Si-based alloy brazing material or A,
It is also possible to re-rad the c-s r-v+g alloy brazing filler metal.

(Function) The present invention uses a pure Al alloy with excellent thermal conductivity as the core material, and clads both or one side of the core material with an Al-Mn alloy with excellent high-temperature strength as a skin material, thereby achieving unprecedented durability. Fins with excellent sagging properties and thermal conductivity are obtained, and various combinations of core material and skin material are adopted depending on the required high temperature strength and thermal conductivity.In other words, both sides of the core material or The skin, clad on one side, may be larger or smaller than the core.

In addition, the fin material of the present invention has a core material clad with a skin material on both sides or one side, and a /l-Si alloy brazing material or an Al-81-Mg alloy brazing material on both surfaces or one surface of the core material, and a plating sheet. It can also be used as

The cladding ratio of the skin material and the brazing material is not particularly limited, but it is necessary to ensure a sufficient amount of the brazing material.

The reason why the components of the core material and skin material are limited as described above is as follows.

In other words, the reason why the Fe content in the core material is limited to 0.25% or less is to improve thermal conductivity and coarsen the grain size to improve sag resistance. rate decreases.

Further, the reason why the Si content is limited to 0.2% or less is to improve the thermal conductivity, and if the content exceeds this, the thermal conductivity decreases.

Furthermore, Zr 0.3% or less, Cr 0.3% or less, Ti 0.3
% or less, Mn less than 0.3%, My 0.3% or less.

Cu0.3% or less, Sn0.1% or less, 1n0. Adding one or more of these within the ranges of i% or less, Zn2.0% or less, and Qa0.4% improves sag resistance, provides sacrificial anode action, and is useful for vacuum brazing. Zn in case
To prevent evaporation, Zr, Qr, Ti, Mn, Mg
, Cu improves sag resistance, Sn, Jn, and ln lower the potential and give sacrificial anode action, and Ca lowers the potential and gives sacrificial anode action, especially when used in vacuum brazing. Although the evaporation of Zn is prevented, if the upper limit is exceeded, the thermal conductivity decreases.

In addition, the reason why the Mn content in the skin material is limited to 0.3 to 2.0% is to improve sag resistance. Below the lower limit, there is no effect, and when the upper limit is exceeded, the effect not only becomes saturated, but also
Reduces thermal conductivity.

Furthermore, Zn2.0% or less, Sn0.1% or less, In0. i
% or less, Zr 0.3% or less, Qr 0.3% or less.

Adding any one or more of Cu 0.3% or less, Mg 0.3% or less, Ti 0.3% or less, and Ca 0.4% or less imparts a sacrificial anode effect and improves sag resistance. Furthermore, 7-n, Sn is used to prevent Zn from evaporating when used in vacuum brazing.

In makes the potential less noble and acts as a sacrificial anode, and Zr and C
r, Cu, Mg, and Ti improve sag resistance, and Ca lowers the potential and provides a sacrificial anode effect, and also prevents evaporation of Zn especially when used in vacuum brazing, but all of them have an upper limit. Exceeding this will reduce thermal conductivity.

In addition, in the structure of the fin material in which both sides or one side of the core material are clad with skin material, it is desirable that the skin material side be made thinner, and it is better to add Znff1 to the skin material in a larger amount than the Znff1 added to the core material. If the potential of the core material becomes less base than the potential of the skin material, the core material will preferentially corrode and bulge-like corrosion will occur, ventilation resistance will increase, and heat exchange performance will decrease, which is undesirable.

(Example) Example (1) Using the core material and skin material shown in Tables 1 and 2, a pair fin material used in conjunction with flux brazing using the fluoride flux shown in Table 3 was produced by a conventional method. . That is, the core material and the skin material are each cast, soaked at 500°C for 3 hours after the face side, hot rolled at 500°C to the desired thickness, and then cold rolled. and intermediate annealing to achieve a thickness of 0.1. It was made of HI3 material. The high temperature strength (sag resistance), electrical conductivity (thermal conductivity), and potential of these fin materials were measured. The results are also listed in Table 3.

Between the sag, as shown in Figure 1, fix the fin material (6) on the fixing base (
7) Protrude 50m from the ceiling and fix it in place ~ eoo' in the gas
The sample was heated at c for 3 minutes and the sag ff1(i) was measured. Moreover, the electrical conductivity was measured by the double bridge method using a sag test sample. Furthermore, the potential was measured in a 5% NaCl aqueous solution. If the front and back sides were different, the potentials were measured separately.

Table 3 For Ichi single-sided cladding materials, the skin material and core H are shown in this order.

As is clear from Table 3, the fin materials of the present invention Nα1 to 13
exhibits characteristics of a sag amount of 15 s or less and a conductivity of 45%lAC3 or more, and uses Zn as the sacrificial fin.

The potential of the fin material of the present invention to which 3n, ln, and Ca are added is -770 to -950 mV, making it possible to protect the aluminum member to be combined with the fin material from corrosion.

On the other hand, the comparative fin material Na14 made only of core material has a large sag amount of 30 m, and the comparative fin material Nα15 made only of skin material, which is a conventional fin material, has a conductivity of 40%lA.
It can be seen that the comparative fin material Nα16, which has a low C3 and high Si content and Fe content in the core material, and the comparative fin material Nα17, which has a low Mn content in the skin material, have a large sag amount of 20 m or more.

Example (2) In the manufacturing process of the present fin materials NQ1, 3, 5.10 and the comparative fin material Nα15 shown in Table 3, JIS 4004 alloy brazing filler metal (Ai-10%5i-1,
A fin material having a thickness of 0.13 sheets as shown in Table 4 and consisting of a vacuum plating sheet was prepared by cladding with 10% Mg alloy (5% Mg alloy). The sag amount and electrical conductivity of these fin materials were measured. The results are shown in Table 4. Sag (2) was measured by protruding the fin material by 50 m and fixing it in the same manner as in Example (1), and heating it in a vacuum at 600° C. for 3 minutes, and the conductivity was measured by the double bridge method using a sag test sample.

Table 4 As is clear from Table 4, the sag amount is 25 M or less, and the N conductivity is 45% lAC3 or more, which is much lower than the comparative fin material Nα22, which is a conventional fin material.

〔Effect of the invention〕

According to the present invention, not only pair fins but also fin materials clad with brazing metal can be dramatically improved in thermal conductivity of the fins without reducing the sag resistance of the fins during brazing. It has significant industrial effects such as being able to improve the heat exchange performance of the vessel.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing the sample holding state in a sag test, Fig. 2 is a perspective view showing an example of a radiator, and Fig. 3 is an explanatory diagram showing a sample holding state in a sag test.
FIG. 1 is a side view showing an example of a pentine type capacitor. 1, fin 2, flat tube 3, header 4, tank 5, extruded tube 6, fin material 7, fixing base Fig. 1 Fig. 2 Fig. 3

Claims (4)

[Claims] (1) Fe0.25wt% or less, Si0.20wt%
The core material is an alloy containing the following, the balance being Al and unavoidable impurities, and Mn0.3 to 2.0w on both or one side.
A fin material for an aluminum heat exchanger, characterized in that the skin material is clad with an alloy containing % Al and unavoidable impurities. (2) Fe0.25wt% or less, Si0.20 in core material
Contains wt% or less, and further contains Zr0.3wt% or less, Cr0
．． 3wt% or less, Ti0.3wt% or less, Mn0.3
Less than wt%, Mg0.3wt% or less, Cu0.3wt%
Below, Sn0.1wt% or less, In0.1wt% or less,
The fin material for an aluminum heat exchanger according to claim 1, wherein an alloy containing at least one of Zn of 2.0 wt% or less and Ca of 0.4 wt% or less, and the balance consisting of Al and unavoidable impurities is used. (3) The skin material contains Mn0.3 to 2.0wt%, and further contains Zn2.0wt% or less, Sn0.1wt% or less, In0
．． 1wt% or less, Zr0.3wt% or less, Cr0.3w
t% or less, Cu0.3wt% or less, Mg0.3wt% or less, Ti0.3wt% or less, Ca0.4wt% or less, and the balance is Al and inevitable impurities. The fin material for an aluminum heat exchanger according to claim (1) or (2). (4) Al-Si alloy brazing filler metal or Al
-Claim (1) in which the Si-Mg alloy brazing filler metal is clad.
, (2) or (3), the fin material for an aluminum heat exchanger.