JPS6333185A - Manufacture of al alloy brazing sheet excellent in corrosion resistance and drooping resistance - Google Patents

Abstract

PURPOSE:To improve the productivity of a product and to extend the life by containing Mn and Zr of the specific wt% in the component and regulating the final cold rolling reduction factor in the range of the prescribed %. CONSTITUTION:The Al alloy of a core material is composed by 0.2-1.5wt% Mn and 0.03-0.15% Zr and the Zr containing amount is regulated >=20% of Fe as the impurity. The coating of Al-Si alloy material is performed on this core material and the rolling reduction factor of the final cold rolling is limited to the range of 5-25%. The component of Zr promotes the coarsening of the crystal grain at the core material brazing time and the crystal grain formation restraining action of Fe is prevented by the Zr containing of >=20% of the impurity of Fe. Owing to the rolling reduction factor of the final cold rolling being restricted the immersion of a brazing filler metal is prevented. In this way, the productivity of a product is improved and the life can be extended because of the corrosion resistance and drooping resistance of the sheet being improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention provides an aluminum alloy with excellent corrosion resistance and droop resistance, which is used as a fin material or tube material of an Al alloy heat exchanger.
The present invention relates to a method for manufacturing an alloy brazing sheet.

[Prior art]

Conventionally, Al alloy play song sheets have been widely used as fin materials and tube materials for Al alloy heat exchangers such as evaporators, condensers, and radiators. As a conventional play song sheet, Mn: 1.0-1.5%,
Al alloy (J
ISΔ3003) as a core material, one or both sides of this core material is coated with AI-3i alloy as a brazing material,
It is known that gJI production is performed with a reduction ratio of 25 to 40% in the final cold rolling after hot rolling.

[Problem that the invention seeks to solve]

However, when the play song sheet manufactured using the chemical composition of the conventional material and its manufacturing method is brazed in an atmosphere at a temperature of around 600℃ as the fin material or tube material of a heat exchanger, the crystal grains of the core material is fine and isotropic, and the molten Al-3i solder penetrates through the grain boundaries of the core material, which deteriorates the sagging resistance at high temperatures, and
Corrosion resistance at room temperature had deteriorated. Deterioration in sagging resistance causes shape deformation and poor brazing, reducing manufacturing yield, while deterioration in corrosion resistance shortens the life of the heat exchanger itself.

[Means for solving problems]

The present invention has been made from the above-mentioned viewpoints, and the present inventors have discovered that the crystal grains of the core material become anisotropic coarse grains during the brazing process, making it difficult for molten solder to penetrate into the core material at high temperatures. As a result of conducting research to develop an Al alloy brazing sheet with excellent sagging resistance during heating and corrosion resistance after high-temperature heating, the following facts were discovered.

(1) In order to make the crystal grains of the core material anisotropically coarse in the high temperature environment during brazing, the core material must contain Mn: 0.2 to 1.5%.
, Zr: 0.03 to 0.15%.

(2) Zr in the core material also contains F, which is an unavoidable impurity.
It has the effect of suppressing the harmful effects of Fe, but in order to achieve this, it is necessary to
It is necessary to contain 0% or more.

(3) A brazing sheet having a core material satisfying the compositions of (1) and (2) above has a final cold rolling reduction of 5
By manufacturing under the conditions of ~25%, its characteristics can be effectively utilized and, as a result, sagging resistance and corrosion resistance can be imparted.

The present invention was made based on the above knowledge, and the reasons for setting each condition will be explained below.

(a) Chemical composition range of core material Mn and Zr are both elements necessary to form anisotropic crystal grains during brazing, and even if one is not contained, sufficient anisotropic crystal grains can be formed. Hard to obtain. Alloys containing these elements generally have a high complete softening temperature, and are characterized by the recrystallization extending greatly in the rolling direction using the driving force of the worked structure formed by rolling during the heating process during brazing. Mn
: less than 0.2%, Zr: less than 0.03%, the effect is not sufficient; on the other hand, Mn: 1.5%, Zr: o, 1
Even if the content exceeds 5%, there will be no further effect, and the processability will deteriorate.

In addition, Zr suppresses the effect of Fe, an unavoidable impurity, on lowering the complete softening temperature and promoting the formation of isotropic crystal grains, but this effect is exerted when the Fe content is 20% or more. be done.

Therefore, the content range is Mn: 0.2% to 1.5%, Z
r: 0.03 to 0.15% and 20% or more of Fe.

(b) Reduction ratio of final cold rolling Since the complete softening temperature of a brazing sheet having a core material of (,) above is high, normal annealing during cold rolling does not completely soften it and some processed structure remains. If the rolling reduction in the final cold rolling is as high as in the production of the conventional brazing sheet using A 3003 as the core material, the crystal grains of the core material formed during brazing are likely to become finer. Therefore, in the brazing sheet of the present invention, it is necessary to suppress the rolling reduction to a low rate of 5 to 25%.
The sagging resistance also decreases.

〔Example〕

Next, the present invention will be explained in more detail based on examples.

Core materials A-E, comparative core materials F and G, conventional core material H, and brazing filler metal, which satisfy the conditions of the present invention and have the compositions shown in Table 1, are melt-produced by the usual melt casting method. After forming into an ingot, it was subjected to homogenization heat treatment under normal conditions.

Next, after this ingot was side-separated, the core material was hot rolled into plates with a thickness of 81 and 911111, and the brazing material was hot rolled to a thickness of 3 (to) and then cold rolled into plates with a thickness of 11. And so. Next, the core material with a thickness of 8"1 was coated with the brazing filler metal on both sides, and the core material with a thickness of 9a+m was coated with the brazing filler metal on one side by hot rolling. After that, this gland material , as appropriate, 370℃ x 2
Cold rolling is carried out while performing intermediate annealing for a certain period of time, and in the final cold rolling, ゛C reduction car is 7%H respectively] 5
Divided into 96,3096 conditions, the final plate thickness is double-sided cladding material: 0.16+1116, single-sided cladding material: 0.32
+am, brazing sheet of the present invention: 1 to 20,
Comparative play song sheets 1 to 14 and conventional play song sheets 1 to 6 were prepared. Table 2 shows play song sheets made of double-sided cran-and wood, and tjS for play song sheets made of single-sided cran-and wood.
They are shown in Table 3. In addition, in Tables 1, 2, and 3, items that are outside the scope of the present invention are marked with an X.

Next, the resulting double-sided clad material was evaluated for its sagging property under high temperatures, and the single-sided clad material was evaluated for corrosion resistance from the solder side by the following tests.

Width: 30 from the above play song sheet in the sagging resistance test
+a+ −6” from room temperature in a vacuum of Torr.
After heat treatment was performed by increasing the temperature to 20° C. and holding it at 620° C. for 10 minutes, the hanging height of the free end of each specimen was measured, and the results are shown in Table 2.

BS indicates a play song sheet (Table 3) BS indicates a play song sheet (Table 3) In addition, in the corrosion resistance test, 40
+a+eX50n+a specimen was cut out and 10-"To
Keto-warm from room temperature to 620 °C in vacuum at 620 °C.
After heat treatment for 10 minutes at ℃, the wax side surface was subjected to an acidic salt spray test for 720 hours, the local corrosion depth was measured, and the results were shown in Ronin 3.

〔Effect of the invention〕

As is clear from Tables 2 and 3, the play song sheet made by the manufacturing method of the present invention has excellent sagging resistance and corrosion resistance at high temperatures, whereas the sheet made by the comparative manufacturing method Play song sheets and play song sheets manufactured using conventional methods have sufficient sagging resistance.
Corrosion resistance has not been achieved.

The pre-plated sheet of the present invention can be similarly applied to brazing in an inert gas atmosphere, for example, by changing the component composition of the brazing material.

As mentioned above, the play song sheet manufactured by the manufacturing method of the present invention has excellent sagging resistance and corrosion resistance, so if used as fin material or tube material for an Al alloy heat exchanger, it will not cause "settling" during brazing. This prevents deformation such as ``deformation'', improves product productivity and yield, and significantly extends the life of the heat exchanger itself.

Claims (1)

[Claims] Al made of core material coated with brazing filler metal on one or both sides
In producing an alloy brazing sheet by a process including hot rolling and cold rolling, the core material is at least Mn: 0.2 to 1.5% and Zr: 0.03 to 0.15%.
And Zr is an Al alloy containing 20% or more of Fe, which is an unavoidable impurity (the above content indicates weight %), and the brazing material is an Al-Si alloy, and the final cold rolling reduction A method for producing an Al alloy brazing sheet having excellent corrosion resistance and drooping resistance, characterized in that the ratio is 5 to 25%.