JPS6199597A - Brazing sheet for vacuum brazing - Google Patents

Abstract

PURPOSE:To improve the brazability, corrosion resistance and strength of a brazing sheet for vacuum brazing by using an Al alloy contg. Cu and Mg at a specified ratio as a core material and an Al alloy contg. Si and Mg at a specified ratio as a facing material. CONSTITUTION:The Al alloy which contains 0.3-1.0wt% Cu and 0.3-0.8% Mg and is added with >=1 kinds among 0.05-0.5% Mn, 0.05-0.5% Zr and 0.05-0.5% Cr is used as the core material. The Al alloy contg. 7-14% Si and 0.05-0.5% Mg is used as the facing material. The above-mentioned facing material is coated on one or both surfaces of the core material to manufacture a brazing sheet for vacuum brazing. The above-mentioned facing material is otherwise coated on the core material and pure Al contg. >=99.0% A as the facing material of a sacrificial anode on the other surface. The brazing sheet for vacuum brazing is highly effective for preventing the contamination of a vacuum surface, vacuum pump, etc. and lessening the deterioration of vacuum performance.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a brazing sheet for vacuum brazing, and more particularly to a brazing sheet for fluff threaded brazing, particularly for vacuum brazing.

[Prior art j Conventionally, core material 400 skin material specified in JIS Z3262 has been used as a brazing sheet for vacuum brazing.
3.4004.4005, N04 crud material and core material 6951 skin material 4343.4045 crud material have been used.

Although these clad materials have good brazing properties, they are used in harsh environments such as condensers, evaporators, engine oil coolers, radiators, and intercoolers for automobile air conditioners. In recent years, higher corrosion resistance and strength have been required.

In addition, in vacuum brazing, recent advances in vacuum technology have made it possible to increase the degree of vacuum in the vacuum furnace.
ttjl+: Oh. . However, scales such as evaporated M may adhere to the furnace wall of the vacuum furnace, and the vacuum pump may be dyed with 7FJ, resulting in poor vacuum performance. li!, such as a decrease in the vacuum level of the vacuum pump or an increase in moisture adhering to the walls of the vacuum furnace. There is a problem of harm occurring.

[Problem to be Solved by the Invention 1] The present invention solves the above-mentioned problems of a clad material in which a skin material is covered with a core material as a plaisong sheet for vacuum brazing, and the vacuum brazing during vacuum brazing. l in the furnace! This product was developed by the present inventor as a result of intensive research in view of the above problems, and has excellent brazing properties, excellent corrosion resistance and strength, and is vacuum brazing that does not cause problems with vacuum furnaces during vacuum brazing. It provides play song sheets for

[Means for solving 8 problems 1] The pre-song sheet for vacuum brazing according to the present invention contains (1) Cu G, 3 to 1.0 wt%, Mg0.3 to
0.3wt%, and 'h(n 0.05-0.5wt%, Zr 0.05~
The core material is an aluminum alloy containing at least lfi selected from 0.5 wt%, Cr 0.05-0.5 wt%, the balance being Al and impurities, Si7-14+wt%, Mg 0. O5~0.5wt%
The first plating sheet for vacuum brazing has a skin material made of an aluminum alloy containing IAI residue and impurities, and has a vf characteristic that the core material is coated with the skin material on one or both sides of the core material.
(2) Cu 0.3-1, Owt%, Mg 0.3
~0.8wt%, Mn 0.05-0.5wt%, Zr 0.05-0.
The core material is an aluminum alloy containing one or more selected from 5vL%, Cr0005-0.5wt%, the balance being Al and impurities, Si214wt%, Mg 0.05-0.5wt
%, with the remainder being Al and impurities, is used as the skin material, aluminum containing 99.0 wt% or more of AI is used as the skin material of the sacrificial anode, and the above skin material on one side of the core material is used as the skin material of the sacrificial anode. This invention consists of two inventions, the second invention being a pre-song sheet for vacuum brazing which is coated with the sacrificial anode coating material on one side.

The pre-song sheet for vacuum brazing according to the present invention will be explained in detail below.

First, the components and component ratios of the core material, the sacrificial anode skin material and the sacrificial anode skin material of the pre-song sheet for vacuum brazing according to the present invention will be explained.

(1) Regarding the core material.

Cu increases the strength of the core H, but the - (Cu) of the core material is considered to be a component that inhibits other products, but in vacuum brazing, Cu increases the strength of the core H.
When used as a core material heated to 620°C, the reduction in corrosion resistance due to Cu content is ignored due to the heating effect and the intergranular corrosion suppressing effect due to the inclusion of one or more of In, Zr, and Cr. It is possible to exhibit the effects of improving strength and potential, and the content is suppressed to the extent possible.
If it is less than 311IL%, no effect of improving strength or V potential can be expected, and if it is contained in excess of 1.0wt%,
Even if g is contained, corrosion resistance deteriorates. Therefore, Cu
The content is 0.3 to 1.0 wt%.

Sig contributes to improving the strength of the core material after brazing, and
When Mg evaporates during vacuum brazing, it acts as a dehydrator, which removes oxygen and moisture in the vacuum furnace and destroys or reduces the oxide film on the surface of the brazing metal. It is possible to reduce the ht content in the brazing filler metal without deteriorating the brazing properties, but if the content is less than 0.3 wt%, no improvement in the strength of the core material can be expected, and the brazing properties will not be improved. I couldn't expect it, and 0.8wt
If the content exceeds %, diffusion into the brazing filler metal during brazing increases, resulting in decreased brazing properties and corrosion resistance. Therefore, M
The g content is 0.3 to 0.3 wt%.

ζ Zr forms an intermetallic compound (A l h Z r ) with Al, and is finely distributed in the core material to strengthen the subgrain and to suppress recrystallization by rolling, extrusion, etc. The metal structure becomes fibrous due to processing, and even after heating during brazing, the crystals do not become equiaxed crystals, but instead become oblate grains extending in the processing direction. It suppresses grain boundary diffusion and prevents increase in a-boundary corrosion susceptibility, and the content is 0.05W.
If the amount is less than t%, these effects are insufficient, and if the amount is less than 0.
If the content exceeds 5 wt%, the effect will be saturated and processability will deteriorate due to the formation of giant crystallized substances. Therefore, Z
The content is 0.05 to 0.5 wt%.

As explained above, Mn and Cr are effective in strengthening the subgrain, suppressing recrystallization, and improving the drawability of the core material. 0.05
If the Mn content is less than 11 L%, such effects are insufficient, and if the Mn content exceeds 0.5 wt%, the susceptibility to intergranular corrosion of the core material tends to increase.
05-0.5wt%, C "Content is 0.05-0.51
It is assumed to be t%.

In addition to these components, an appropriate amount of Ti may be included during casting, and impurities such as Si up to about 0.2 wt% and Fe up to about 0.7 wt% are allowed.

(2) Regarding the leather material.

Si is a basic component of aluminum brazing material, has a lower melting point than the brazing material, provides fluidity during brazing, and improves the corrosion resistance, strength, workability, etc. of the brazed part. Considering this, if the content is less than 7 wt%, such an effect cannot be expected, and if the content exceeds 14 wt%, the effect will be saturated and it will be wasteful. Therefore,
The Si content is 7 to 14 wt%.

Mg is required to destroy at least the oxide film on the surface of the brazing material due to the defter action of Mg during laxless vacuum brazing. Indirect defter action alone through diffusion into the brazing filler metal does not have the above effect. Therefore, if the content is less than 0.05 wt%, there is no such effect, and if the content exceeds 0.5 wt%, evaporation will occur. An increase in M8 causes contamination of the vacuum furnace and deterioration of vacuum performance. Therefore, Mg content is 0.05
~0.5wt%.

(3) Regarding the skin material of the sacrificial anode.

As the core sacrificial anode skin material, an aluminum material with a lower potential than the core material must be used, and as such a sacrificial anode skin material, pure aluminum with an AI of 99.0 wt% or more is preferably used. Furthermore, in order to make the potential of pure Al more base, aluminum containing 0.5 wt % or less of heptads may be used, and aluminum containing 0.2 wt % or less of Cu may be used.

] Example 1 Next, an example of a plain nongloss sheet for vacuum brazing according to the present invention will be described.

EXAMPLES Core materials, skin materials, and sacrificial anode skin materials having the components and component ratios shown in Table 1 were manufactured by melting casting and processing in a conventional manner.

Three types of skin materials (A-1 to A-3) are applied to one side of seven types of core materials (B-1 to B-7), and sacrificial anode skin materials (C-1) are applied to the other side. , thickness 0.4am, width 200mm,
Coverage rate 10% (skin material, sacrificial anode skin material, thickness 0.0-4m
Nine types of play songs (m) were prepared.

Using the pre-song sheet sample material produced in this way, a brazing property test during vacuum brazing and the amount of Mg evaporation in the pre-song sheet were measured.

In addition, the strength and corrosion resistance of the sample materials after vacuum brazing were tested.

The results are shown in Table 1)152.

*1 Brazing properties were evaluated based on the flow coefficient.

From the play song sheet sample material, width 2SmeX length 50
Cut out the specified sample, and assemble the board 4 (A3003) of thickness 0.5 mm
The temperature was raised to 595°C in a vacuum of 2 x 10-'' Torr (heating time 32 minutes), held for 2 minutes, and then cooled. and evaluated the brazing properties.

Flow coefficient 0.5 or more 00.3~0.
49 Δ Less than 0.3 × *2 The amount of M8 evaporation (g/dm2) is determined by calculating the difference (8) in the M8 content in the play song sheet before and after vacuum brazing.
The surface area of the play song sheet (shown as the value divided by di).
Cut out a plate with a length of 2004 mm and heat it in a vacuum furnace at a vacuum degree of 2
After heating and holding at a temperature of 10-'' Torr and 595'C for 2 minutes (heating time: 29 minutes), it was cooled down.

X3 Strength (σ, kg/as') is a value obtained by performing a tensile test using a JIS No. 5 test piece from a vacuum-brazed play song sheet to determine the tensile strength. Incidentally, the vacuum brazing of the pre-song sheet test material was carried out under the same conditions as described above.

×4 Corrosion resistance was determined by conducting a cast test on the skin side of vacuum-brazed pre-song sheet specimens, and an immersion test in corrosive liquid on the sacrificial anode skin side, and measuring the lifespan until penetrating the plate thickness of 0.4-mm. A comparative evaluation was made.

Time to penetrate the plate thickness 0.4+s in the skin material Il capacity test 200 hours or more 0 100 to 200 hours Δ ioo * r + u full x Plate thickness 0.4- in the sacrificial anode skin material side corrosive liquid immersion test Time to penetration: 2 months or more ○ (1 to 2'''' 4 Less than 1 month
A 0m plate was cut out and subjected to a cast test and a corrosive liquid immersion test.

The immersion test was carried out in an 88°C corrosive solution (C1”12 in solution 11).
5 5ppm, 5ot-260pp+s, Cu
” 1 ppm.

330 ppm in Fe, pH 4,5) at 8 o'clock wI
immersion, then left at room temperature for 16 hours, and repeating this immersion in the corrosive solution and leaving at room temperature every 24 hours,
This is the result of testing until the test piece penetrated.

As is clear from this Table 2, the pressing seams for vacuum brazing according to the present invention (Nos. 1 to 1).

4) has excellent brazing properties, low Mg evaporation, high strength after brazing, and excellent corrosion resistance.

Comparison materials No. and S play song sheets are made of leather material (4004
Due to the high Mg content (equivalent), the amount of Mg evaporated during brazing is extremely high, contaminating the vacuum furnace and vacuum pump, and significantly deteriorating the vacuum performance.

Comparative material No. 6, the play song sheet, is made of leather material (4045
It is recognized that the brazing properties are reduced due to the low M content (equivalent), and it is therefore clear that it is necessary to include a certain amount of Mg in the skin material.

Comparative material No. 7, the play song sheet, has high strength after brazing, but has significantly poor corrosion resistance and poor brazing properties, and the Mg evaporation amount is somewhat high because the core material has a high Mg content.

Comparative material 8, the play song sheet, has a low Mg content in the core material, so the amount of Mg evaporation is the lowest, and the corrosion resistance is good, but the strength is low and the brazing property is also significantly reduced. . Therefore, it can be seen that there is a suitable range for the N1g content of the core material.

Comparative material No. 9, the play song sheet, has a small amount of Mg evaporation and good brazing properties, but its strength after brazing is low and its corrosion resistance is significantly reduced. This is because the content is low.

Therefore, if the core material has a high Cu content, even if high strength is obtained, corrosion resistance will be reduced. Therefore, it can be seen that there is an optimum range of Cu content 1 in the core material in view of the balance between strength and corrosion resistance.

[Effects of the Invention] As explained above, since the vacuum brazing play song sheet according to the present invention has the above-mentioned configuration, it has excellent vacuum brazing properties, and also has excellent vacuum brazing properties. It has excellent corrosion resistance and strength, and has the excellent effect of causing very little contamination of vacuum furnaces, vacuum pumps, etc., and very little deterioration of vacuum performance.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the assembly of a test piece for a brazeability test. X... play song sheet, 1... core material, 2... leather material,
3. The skin material of the sacrificial anode.

Claims (2)

[Claims] (1) Cu0.3-1.0wt%, Mg0.3-0.
Contains 8wt%, and Mn0.05-0.5wt%, Zr0.05-0.5w
The core material is an aluminum alloy containing one or more selected from t%, Cr0.05-0.5wt%, and the balance is Al and impurities, and Si7-14wt% and Mg0.05-0.5wt%. A brazing sheet for vacuum brazing, characterized in that the skin material is made of an aluminum alloy containing Al and the remainder is Al and impurities, and one or both sides of the core material are coated with the skin material. (2) Cu0.3-1.0wt%, Mg0.3-0.
Contains 8wt%, and Mn0.05-0.5wt%, Zr0.05-0.5w
The core material is an aluminum alloy containing one or more selected from t%, Cr0.05-0.5wt%, and the balance is Al and impurities, and Si7-14wt% and Mg0.05-0.5wt%. The aluminum alloy containing 99.0 wt% or more of Al is used as the skin material of the sacrificial anode, and the skin material is on one side of the core material, and the sacrificial material is on the other side of the core material. A brazing sheet for vacuum brazing that is characterized by being individually coated with anode skin material.