JPS60138083A - Composite al alloy material for fin of heat exchanger having superior strength at high temperature and significant sacrificial anode effect - Google Patents

Abstract

PURPOSE:To obtain a composite Al alloy material for the fins of a heat exchanger having superior strength at high temp. and a significant sacrificial anode effect by cladding both sides of a core material of an Al alloy contg. specified amounts of Mn and Zn with a shell material of an Al alloy contg. specified amounts of Sn and Zn. CONSTITUTION:Both sides of a core material of an Al alloy having a composition consisting of 0.1-1.5wt% Mn, 0.01-0.5wt% Zn and the balance Al with inevitable impurities are clad with a shell material of an Al alloy having a composition consisting of 0.03-0.12wt% Sn, 0.01-0.3wt% Zn and the balance Al with inevitable impurities.

Description

DETAILED DESCRIPTION OF THE INVENTION When manufacturing a heat exchanger by brazing fin materials and tube materials, the present invention provides that brazing has high-temperature strength that exhibits excellent sagging resistance against heating during heating. However, brazing is related to a composite fin material made of AQ alloy for heat exchangers that exhibits an excellent sacrificial anode effect on the subsequent tube material.

In general, M alloys are lightweight and have excellent thermal conductivity.

Since it also has excellent corrosion resistance, it is widely used, for example, in the manufacture of heat exchangers such as automobile radiators. This heat exchanger includes, for example, a pipe material made of a pre-song sheet made of an AQ-Mn alloy as a core material and one side of the core material clad with an AA-8i alloy brazing material; Combined with Mn-based alloy fin material,
The assembly is manufactured by brazing without 7 lux in vacuum or inert gas, or by brazing with 7 lux in low pressure air.

Therefore, it goes without saying that the fin material of a heat exchanger is required to have sufficient sagging resistance, that is, high-temperature strength, so that it will not deform when heated above the melting temperature of the brazing material during brazing. In particular, in practical use, it is required that the sacrificial anode exhibit a sufficiently satisfactory sacrificial anode effect on the pipe material.

However, in the above-mentioned AQ-Mn alloy fin material, it cannot be expected to exhibit a satisfactory sacrificial anode effect because it is not electrochemically sufficient to form a ring with respect to the tube material.

From this point of view, 〇-Mn can be used as a fin material for heat exchangers.
An Ag-Mn-Zn alloy has been proposed in which the alloy contains about 1-2% of Zn to make it electrochemically less noble, thereby fully exerting the sacrificial anode effect on the pipe material. Fin materials made of AR-Mn-Zn alloys exhibited excellent sacrificial anode effects when the heat exchanger was manufactured by brazing in an inert gas atmosphere or in the air, but the high-temperature strength was poor. Furthermore, when a heat exchanger is manufactured by brazing in a vacuum using this, the Zn content is high and Zn has a high vapor pressure, so During brazing, a large amount of Zn in the fin material evaporates, and the remaining amount becomes small, resulting in a low sacrificial anode effect on the tube material, and problems such as furnace contamination due to Zn evaporation occur. .

Therefore, from the above-mentioned viewpoint, the present inventors recognized that it would be extremely difficult to construct a fin material with high-temperature strength and sacrificial anode effect from a single material. As a result of research to ensure that by constructing the heat exchanger fin material with composite materials, we found that the fin material for heat exchangers has
(Hereinafter, ``H'' indicates weight %), Mn: 0.1 to 1.5%.

Zn: 0.01-05%.

Contains, and if necessary, Mg: O, Ol ~ 1%.

Cu: 0.01-0.2%.

Zr: 0.0 2-0.2%.

Cr: 002-03'L%.

Sn: 0.03 to 0.12% on both sides of a core material made of 48 alloy having a composition containing one or two of the above, and the remainder consisting of AQ and unavoidable impurities.

Zn: 0.01-0.3%.

Contains, and if necessary, Mg: O, Ol ~ 1%.

When constructed with an Aε alloy composite cladding made of AQ alloy cladding having a composition containing M and the remainder consisting of M and unavoidable impurities, the core material ensures excellent sagging resistance (high temperature strength). In addition, since the Zn content is relatively low in the above-mentioned skin material, the evaporation of Zn during vacuum brazing is suppressed as much as possible, and S
Since the coexistence with n sufficiently forms a ring electrochemically, it was discovered that this skin material ensures an excellent sacrificial anode effect.

This invention has been made based on the above findings, and the reason why the component compositions of the core material and the skin material are limited as described above will be explained below.

A. Core material (a) Mn The Mn component forms a compound with M, and is finely dispersed and precipitated in the matrix, significantly increasing the recrystallization temperature of the alloy. As a result, during brazing, recrystallized grains are formed during heating. Coarsening and brazing have the effect of improving the sagging resistance (high temperature strength), but if the content is less than 0.1%, the desired effect cannot be obtained; on the other hand, if the content exceeds 1.5% Even if it is included, not only will it not be possible to obtain further improvement effects, but also it will form giant parts during melting and casting, impairing workability, and further reducing thermal conductivity. Its content is set at 0.1 to 15 chi.

(b) Zn The Zn component in the core material is contained for the purpose of replenishing a small amount of Zn that evaporates from the skin material during vacuum brazing addition heat. Zn cannot be replenished satisfactorily to the skin material at times, and on the other hand, if the content exceeds 0.5%, a large amount of Zn will evaporate through the skin material.
01 to 05 section.

(c) Mg and Cu These components dissolve in solid solution in the base material and have the effect of strengthening it, so they are included as necessary when particularly strength is required, but the content is Mg: 0.0 each
If the content is less than 1% and Cu: less than 0.01%, the desired strength improvement effect cannot be obtained, while if the Mg content exceeds 1%, the sagging resistance (high temperature strength) will be significantly reduced.
However, if the Cu content exceeds 0.2%, it becomes electrochemically extremely noble and loses its sacrificial anode effect on the pipe material, so the content is adjusted to Mg: 0.01~ 1%, Cu: 0.01-0.
It was set at 2%.

(d) Zr and cr When these components coexist with Mn, they form a compound with M, finely disperse and precipitate in the matrix, further raising the recrystallization temperature of the alloy, and thus brazing is difficult during heating. Since it has the effect of coarsening recrystallized grains and improving sagging resistance, it is included as necessary especially when even higher sagging resistance is required. 02
% and Cr: less than 0.02%, the desired sagging resistance improvement effect cannot be obtained, while Cr: 0.3% and Zr:
If the content exceeds 0.2%, it becomes easy to form giant pieces during melting, reducing workability, and further improving the sagging resistance is not achieved. Zr: 0.02-0.2%, Cr: 0.
It was set at 02-03%.

B. Skin material (a) Sn and Zn These components have the effect of electrochemically making the skin material base in the coexistence of the same components, giving it an excellent sacrificial anode effect, and also improving its feeding properties. It has an effect.

Therefore, even if the Sn content is less than 0.034% or the Zn content is less than 1%, excellent sacrificial anode effect and corrosion resistance cannot be ensured. and Zn: Even if the content exceeds 0.3%, not only the desired effect of improving the above action cannot be obtained, but also the workability deteriorates.
The content is Sn: 0.03-0.12%, Zn
: It is set at 0.01 to 0.3 chi.

(b) Mg The Mg component has the effect of improving the corrosion resistance of the skin material without almost changing the electrochemical properties of the skin material.
In particular, it is included as necessary when corrosion resistance is required, but if the content is less than 0.014, the desired effect of improving corrosion resistance cannot be obtained, while on the other hand, if it is contained in excess of 1. The content is reduced to 0.01 because it does not provide any improvement effect and causes deterioration of workability.
~1ch.

Next, the composite fin material of the present invention will be specifically explained using examples.

Example An M alloy for the core material and an M alloy for the skin material each having the final component compositions shown in Table 1 were melted by a conventional melting method,
After casting into an ingot, it is homogenized under normal conditions, and then processed into these alloy ingots. Among the alloy ingots, A2 alloy for the core material is hot-rolled under normal conditions to obtain a plate thickness of 8. This hot-rolled sheet was then similarly hot-rolled to M alloy for skin material under normal conditions to obtain a hot-rolled sheet with a thickness of 5 mm, which was then cold-rolled to obtain a sheet. A cold-rolled plate with a thickness of 1 mm was prepared, and then the A1 alloy hot-rolled plate for the core material with a plate thickness of 28 mm and the M alloy cold-rolled plate for the skin material with a plate thickness of 1 mx were formed in the same way. In the introduction shown in Table 1, the AQ alloy cold-rolled sheet for the skin material is superimposed on both sides of the A2 alloy hot-rolled sheet for the core material, and the superposed body is hot-rolled under normal conditions. The plate is cladded with 3U to give a plate thickness of 3U, and then subjected to appropriate intermediate annealing and then cold rolled (final cold working rate: 30%).
Two types of composite fin materials 1 to 27 made of the AQ alloy of the present invention having plate thicknesses of 05 wrL and 0.16 wIL were manufactured by applying the following steps.

For the purpose of comparison, an A9 alloy having the same final component composition shown in Table 1 was melted and cast.

After the homogenization treatment, this was hot rolled under normal conditions to obtain a hot rolled sheet with a thickness of 5 TuL, followed by appropriate intermediate annealing and then cold rolling (final cold working rate: 309 J). )
Two types of conventional AA alloy fin materials having plate thicknesses of 0.5 m and 016 M were manufactured by applying the following steps.

Next, a drooping resistance test was conducted for the purpose of evaluating high-temperature strength using the composite fin materials 1 to 27 made of the M alloy of the present invention and the conventional fin material made of the AA alloy, each having a plate thickness of 0.16 m.

The sagging resistance test was conducted using a sample as a width: 30+u+X length:
Using a specimen with a dimension of 140M, the part 30111111 from one end in the length direction of this specimen was held horizontally in a vacuum of about 10""' torr at a temperature of 620
The test was carried out under the condition of being held at ℃ for 5 minutes, and the hanging height of the tip was measured.

Further, using the specimens after the sagging resistance test, the potential for pitting corrosion in 1N saline (saturated calomel standard) was measured for the purpose of evaluating the sacrificial anode effect.

Furthermore, the above plate thickness: 0.5M composite fin materials 1 to 27 made of the M alloy of the present invention and the width of the conventional fin material made of the M alloy: 2
Cut out a specimen with dimensions between ONX length = 50, and use this specimen as a separately prepared width: 40 + 11111X length: 5
0MX plate thickness: 1M dimensions, Mn: 1.21%,
AQ and unavoidable impurities: On one side of a core material with a thickness of 0.9u+ having a composition consisting of the remainder, Si: 9.50%,
Mg: 1.53, 2M, and unavoidable impurities: Residue: The center of the length of an M alloy plate, which is usually used as a pipe material, and is made by cladding with a thickness of 20, 'llK++1. Hold it upright at right angles to the line,
In this state, brazing was carried out in a vacuum at a temperature of 620°C for 5 minutes.
A tap water immersion test of 30 days immersion in 0°C tap water and a 30 day CASS test were conducted to determine the number of occurrences of pitting corrosion and the maximum pitting depth in the M alloy plate material commonly used as pipe material after the test. It was measured.

These measurement results are also shown in Table 1.

From the results shown in Table 1, as is clear from the comparison between the composite fin material 5 made of the M alloy of the present invention and the conventional fin material made of the M alloy, which have almost the same Mn content, the composite fin material 1 made of the M alloy of the present invention ~27 all have excellent droop resistance (high temperature strength) equivalent to conventional A8 alloy fin materials, while the sacrificial anode effect is even better than conventional M alloy fin materials. It shows.

The various Aε alloys shown in Table 1 all contain Mn: 0.01% or less and Cu: 0 as unavoidable impurities.
,01% or less, Cr:0.01% or less, Zr:O,01
% or less, Si: 0.3% or less, and Fe: 0.4% or less.

As mentioned above, the M alloy composite fin material of the present invention has excellent high temperature strength (sagging resistance), so the brazing applied when manufacturing the heat exchanger is
Not only does it not cause any sag, so good brazing can be achieved, but it also has electrical properties that are electrochemically sufficient for the pipe material to be brazed. It exhibits a sufficient sacrificial anode effect on the tube material and has excellent corrosion resistance, and has industrially useful properties such as making it possible to significantly extend the life of heat exchangers.

Claims (8)

[Claims] (1) Mn: 0.1-1.5%. Zn: 0.01-0.5%. 42 alloy core material containing 0.03 to 0.12% Sn2 and Zn:0. O2N2.3chi. An M alloy composite fin material for a heat exchanger, which has excellent high-temperature strength and sacrificial anode effect, and is made by cladding an A9 alloy skin material having a composition (by weight %) of AA and unavoidable impurities. (2) Mn: 0.1-1.5% tZn: ,
O, Ol~0.5%. and further contains Mg: 0.01 to 1 t. Cu: 0.01-0.2%. Sn: 0.03 to 0112% on both sides of an M alloy core material having a composition containing one or two of these, with the remainder consisting of M and unavoidable impurities. Zn: 0.01-0.3%. A1 for heat exchangers with excellent high-temperature strength and sacrificial anode effect, made by cladding with A1 alloy skin material having a composition (by weight %) containing
Alloy composite fin material. (3) Mn: 0.1 to 1.5 To. Zn: 0.01-0.5%. and further contains Zr: 0.02 to 0.2%. Cr: 0.02-0.3%. Sn: 0.03 to 0.12% on both sides of an A1 alloy core material having a composition containing one or two of the above, and the remainder consisting of M and unavoidable impurities. Zn: 0.0 1-0.3%. An AQ alloy composite fin material for a heat exchanger, which has excellent high-temperature strength and sacrificial anode effect, and is made by cladding an M alloy skin material having a composition (by weight %) containing Aε and unavoidable impurities. (4) Mn: 0. IN1.5%. Zn: 0.01-0.5%. and further contains Mg: O, Ol to 1. Cu: 0.01-0.2%. One or two of the above, and Zr: 0.02 to 0.2%. Cr: 0.02-0.3%. Sn: 0.03 to 0.12% on both sides of an A1 alloy core material containing one or two of these, with the remainder being AA and unavoidable impurities. Zn: 0.01-0.3%. AQ for heat exchangers with excellent high-temperature strength and sacrificial anode effect, made by cladding with M alloy skin material having a composition (type, quantity) containing AQ and unavoidable impurities.
Alloy composite fin material. (5) Mn: 0.1-1.5%. Zn: 0.01-0.5%. Sn: 0.03-0.12%. Zn: 0.01-0.3%. Mg: 0.01 to 1 t. An Al1 alloy composite fin material for a heat exchanger, which has excellent high-temperature strength and sacrificial anode effect, and is made by cladding an M alloy skin material having a composition (by weight %) of M and unavoidable impurities. (6) Mn: 0.1-1.5%. Contains Zn: 0.01 to 0.5'16°, and further contains Mg: 0.01 to 1%. Cu: 0.01-0.2%. Sn: 0.03 to 0.12% on both sides of an A9 alloy core material having a composition containing one or two of the following, with the remainder consisting of M and unavoidable impurities. Zn: 0.01~O, 3chi. Mg: 0.01 to 1 t. M for heat exchangers with excellent high-temperature strength and sacrificial anode effect, which is made by cladding AP and alloy skin material with a composition (by weight %) containing Ag and unavoidable impurities.
Alloy composite fin material. (7) Mn: 0.1-1.5%. Zn: 0.01-0.5%. and further contains Zr: 0.02 to 0.2%. Cr: 0.02-0.3%. Sn: 0.03 to 0.12% on both sides of an M alloy core material containing one or two of the above, with the remainder consisting of AQ and unavoidable impurities. Zn: 0.01-0.3%. Mg: 0.01-1%. AQ for heat exchangers with excellent high-temperature strength and sacrificial anode effect, which is made by cladding A1 alloy skin material with a composition (by weight %) containing AQ and unavoidable impurities.
Alloy composite fin material. (8) Mn: 0.1-1.5%. Zn:0101~05chi. and further contains Mg: 0.01 to 1%. Cu: 0.01-0.2%. One or two of these and Zr: 0.02 to 0.2%. Cr: 0.02-0.3%. Sn: 0.03 to 0.12% on both sides of an M alloy core material having a composition containing one or two of the following, with the remainder consisting of M and unavoidable impurities. Zn: 0.01-0.3chi. Mg: 0.01 to 1 t. An AQ alloy composite fin material for a heat exchanger, which has excellent high-temperature strength and sacrificial anode effect, and is made by cladding an M alloy skin material containing AQ and unavoidable impurities (weight percent).