JPS58113347A - Heat exchanger made of brazed aluminum - Google Patents

Abstract

PURPOSE:To enhance the corrosion resistance of the titled heat exchanger by using an Al-Cu alloy as the plate material or the matrix material, an Al-Si alloy contg. restricted Fe as an impurity as the brazing filler metal, and pure Al contg. restricted Cu and Fe as impurities as the core material. CONSTITUTION:This heat exchanger made of brazed Al is formed by combining a matrix plate 1 having many holes with fins made of a brazing sheet 2 and by brazing them. At this time, an alloy consisting of, by weight, 0.2-2.0% Cu and the balance essentially Al or further contg. one or more among 0.01-0.5% each of Mn, Cr and Zr is used as the material 1. An Al-Si or Al-Si-Mg alloy contg. <=0.25% Fe as an impurity is used as the brazing filler metal of the sheet 2 for the fins. Pure Al or an Al-Mn or Al-Mg-Si alloy contg. <=0.1% Cu and <=0.2% Fe as impurities is used as the core material of the sheet 2.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a brazed aluminum polar heat exchanger using plating sheet fins with improved corrosion resistance.

Aluminum alloy has generally been widely known as an alloy material with excellent corrosion resistance, but when used as a brazed structure such as a heat exchanger, for example, kl-8i
Since the brazing filler metal acts as a cathode for the KL base metal, corrosion is electrochemically accelerated, and corrosion resistance becomes insufficient, so some kind of countermeasure against this problem is desired.

The present invention has been made in view of the above-mentioned actual situation and to improve the situation.As a fluid passage constituent member that is subject to pupil damage due to penetrating corrosion, the present invention has excellent corrosion resistance after brazing. The life of the brazed aluminum heat exchanger can be extended by using an alloy that has a positive electric potential, and by using an alloy that is more efficient than the fluid passage component for the fins, which will not cause fatal damage even if they corrode. The structure is an aluminum heat exchanger that uses a plate material or a shape material and a fin made of a vine plating sheet. (The meaning of electric power is the same as below 2), or this and Mn, Cr, Z
r (7) of which 181 or more: using an alloy containing 0.01 to 0.5% each, with the remainder consisting of AI and unavoidable impurities, as a brazing material for a plating sheet for fins, 0.25' of Fe or 0.25' of impurity Using a kl-5i-based or kl-5i-Mg-based alloy that is less than ll, and as a core material,
Impurity Cu is 0.1% or less and -) Fe is 0.2%
Pure Afi system, Al-M n system or kl-M which is below
The gist lies in the use of g-5i alloy. In this aluminum heat exchanger, the core material of the fin plating sheet contains Zn: 0.1 to 1.0% and Sn:
0.01~0.1'lG and In:Q, Ql~0.1%
If one or more of these are included, the performance can be increased to 1: ¥.

The specific contents of the present invention will be further explained in detail below.

First, the material used as the fluid passage component is 0.2~
Contains 2.0 g of Cu as an essential component, and further contains 0.01 to 0.5% of Mn, Cr, and Zr (11% of D) as necessary.
1 [or two or more, with the balance consisting of Afi and impurities; on the other hand, fins are F@ as impurities or kl-5i or Al-5i of 0.25'% or less.
A brazing filler metal made of a 51-Mg alloy and F as an impurity
Pure aluminum with less than 0.2% e and 0.1% copper,
Al-Mn-based, Al-Mg-5i-based alloys and, if necessary, further added Zn of 0.1 to 1.0 to these alloys.
It is composed of a plating sheet whose core material is an alloy containing one or more of 0.01 to 0.1% (y) Sn and In, with the remainder being Al and impurities.

In the present invention described above, the blending amount of each component of the fluid passage component and the composition of the fin material constitute the vehicle equipment features of the present invention, and if the above conditions are met, the intended results of the present invention will not be achieved. I can't get it.

In other words, Cu in the A1 alloy is known as a component that improves strength and shifts the potential in a negative direction.
Since corrosion resistance is affected by the addition of Cu, corrosion-resistant aluminum alloys are generally used in which the amount of Cu added is suppressed to 0.2% or less. However, when assembling A41 alloy material by brazing, Al-
In order to melt the 8i brazing filler metal, high-temperature heating of 570 to 610°C is applied, or even if such high-temperature heating is applied, if one containing a relatively large amount of Cu is used as described above, It has been found that the Cu additive component acts effectively as a strength-improving component and a potential-improving component without substantially lowering the subsequent corrosion resistance.

In the present invention, it is not possible to sufficiently improve the potential of the base material with Cu cooling filter or 0.2% powder droplet of the alloy for the fluid passage component, so it is necessary to add Zn, Sn, 10, etc. to the fin material. In addition, it is necessary to add each element at a higher concentration than in the present invention, resulting in contamination of the brazing furnace and a decrease in workability (Also, if Cu increases beyond the upper limit of 2%, the potential On the other hand, the corrosion resistance decreases.Therefore, 0.2 to 2 liters was selected as an appropriate range that does not reduce the corrosion resistance too much and maintains the potential.

Next, in addition to Cu, kin, Cr,
Zn is effective in suppressing recrystallization during brazing heating and improving strength, and if it is less than 60.01% of each element, the effect will not be exhibited effectively, and if it exceeds 0.5%, corrosion resistance will decrease and processing will be affected. It leads to a decline in sexuality.

Therefore, the amount added is preferably 0.01 to 0.5%, and 3%.
The total content of the elements is preferably less than 1.0%.

Further, the reason why Fe, which is an impurity in the brazing filler metal for fin plating sheets in the present invention, is limited to 0.25% or less is to improve general corrosion resistance and to prevent potential damage. Al3-5i yarn or kl-8i-M
Fe in the g-thread brazing material forms an intermetallic compound such as FeSi or) e S s 2 with Si in the brazing material, which crystallizes during brazing.

These FeSi-based compounds have higher potential than crystallized SiJ and have a greater effect as an effective cand. Therefore, as the Fe content in the brazing filler metal increases, the potential shifts to the higher direction, and the general corrosion resistance also decreases. descend.

If the Fe content in the brazing filler metal is less than 0.25%, this effect will be small; if it exceeds 0.3%, it will cause problems such as cracking of the upper punch and a decrease in corrosion resistance, so impurities in the brazing filler metal The upper limit of Fe was set to 0.25%. Next, upper limits were set for Fe and Cu impurities in the plating sheet core material in order to prevent potential damage.

As for the alloy system for the core material, depending on the potential, corrosion resistance, and brazing properties, there are U strong FK, K full i (JISIXXX), A/-M
n (f13XXX), kl-Mg-8i (6XXX)
is preferred.

Here: L41CJIS 6XXX) and 4iJIs
600011 means one alloy such as 6001. In addition, for applications that require active cathodic protection using fins, 0.1 to 1.0% Z is added to these alloy systems.
Preferable results can be obtained by adding 181 or two or more of Sn, In, and Sn in an amount of 0.01 to 0.1%.

In each case, the effect is insufficient when the lower limit value is exceeded, and although the effect can be obtained when the upper limit value is exceeded, it is not desirable because it contaminates the furnace and builds up secondary deposits such as reduced workability. .

Thus, by selecting the compositions of the components of the fluid component and the plating sheet for fins as described above, corrosion resistance can be significantly improved.

Next, the present invention will be explained in more detail with reference to Examples.

Example First, alloys having each component set 1ik shown in Tables 1, 2, and 3 were prepared. Table 1 shows members for configuring fluid passages, 41
- 8 are materials of the present invention, and 9 - 11 are similar comparative materials to the U-compound metal material. Further, Table 2 shows brazing materials for plating sheets, and A21-22 are materials of the present invention and A23 is a conventional material. Table 3 shows alloys for core materials of plating sheets for fins, where &31-40 are materials of the present invention and M41-43 are similar comparative materials. Note that the heat exchanger of the present invention is constructed by a combination of the above-mentioned members that meet the requirements of the invention.

Using an alloy with the composition shown in Table 1, the first
Figure: A multi-hole material with the cross-sectional shape shown in this figure was created.

Further, a plating sheet having a cladding ratio of 10% and a plate thickness of 0.5 ff was prepared by combining the brazing filler metal shown in Table 2 and the core material alloy shown in Table 3. The multi-hole mold material (1) and plating sheet (2) are assembled into the shape shown in Fig. 2 and heated in a vacuum (1).
A sample material was prepared by heating at 595°C for 3 minutes at a temperature of 0-' to 10-'To...). A CASS test according to JISH8681 was conducted on this sample material.

Table 4 shows the maximum feeding depth after 500 hours of continuous testing.
Reference photos 1 to 4 show typical cross-sectional corrosion conditions.

Table 2 Chemical composition of plating sheet brazing filler metal (&fi
i%) Table 3 Chemical composition of praising sheet core material (j
k & %) All of the combination materials according to the present invention have slight defects, but no matter which fins are used for the conventionally used 50 large material, and 3003 multi-hole material-A.
Clear penetration corrosion also occurred with the AQ plating sheet combination.

Did you explain about the multi-hole heat exchanger in the above article? $39
14 As shown, plate material (3) and brazing fins (4)
) almost similar results were obtained for the plate-fin heat exchanger.

As described above, the present invention constitutes a heat exchanger by combining a fluid passage forming material made of an alloy with a specific composition and a plating sheet fin material compatible with the fluid passage forming material, and the synergistic effect of each member is achieved. This results in improved corrosion resistance. As a result, the number of parts damaged due to corrosion can be prevented, and the performance can be significantly improved compared to conventional aluminum heat exchangers.

[Brief explanation of the drawing]

1 is a cross-sectional diagram of the multi-hole material used in the examples, FIG. 2 is a schematic diagram of the assembly of the sample material, and FIG. 3 is a schematic cross-sectional diagram of the plate-fin type heat exchange element.

Claims (2)

[Claims] (1) For aluminum heat exchangers that use plates or shapes and fins made of plating sheets,
As a plate material or a shape material, Cu: 0.2 to 2.0 哄 (meaning 2 or less of the meaning of storm quantity 哄 is the same), or this and Mn. One or more of Cr%Zr: each contains 0801 to 0.5-, the balance is Ag and unavoidable impurities, and as a brazing material for a plating sheet for fins, the impurity F@0.25% is used. Al-8i series or Ag
-84-Mg-based alloy is used, and the core material is pure An-based, Al-Mn-based, or kl-Mg-8i with impurity Cu of 0.1 or less and ke of 0.2 or less. A brazed aluminum-grade heat exchanger characterized by being made of an alloy of the above-mentioned type. (2) Core material of plating sheet for fins Zn: 0
．． 1-1.0%, Sn:Q, 01-0.1911 and I
The heat exchanger according to claim 1, which contains one or more of n:Q, Ql to 0.1 liters.