JPS6038457B2 - Aluminum alloy for brazing sheet brazing material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for manufacturing aluminum and aluminum alloy products used in extremely corrosive environments by brazing in a vacuum or inert gas atmosphere. The present invention relates to an aluminum alloy suitable for use as a blank in plating sheets used.

Conventionally, in general, for example, radiators of motorcycles and automobiles, condensers of coolers, and evaporators (
In the production of heat exchangers (hereinafter collectively referred to as heat exchangers),
A standard 1050 material (99.00% purity AI), same 10
70 material (99.7% purity AI), 3003 material (N-
Yamaichi 7-15% Sj alloy, AI-3-15% Si-0.3, etc.
A plating sheet made of clad aluminum alloy such as Mg alloy as a brazing material is used as the fin material, and this fin material is -1.0
~1.5%Mn-0.8~1.3%Mg), and 5
The heat exchanger is manufactured by brazing aluminum and aluminum alloys such as 009 material (N-0.5 to 1.1% Mg) in manufactured tubes or in an inert gas atmosphere.

However, in a heat exchanger in which the fin core material and the tube body are brazed and joined by brazing of different materials, the entire surface of the fin core material and the joint with the fin core material in the tube body are However, because they are covered with a high natural potential, a local battery is formed in both of them, and when the heat exchanger is exposed to a particularly harsh corrosive environment, corrosion progresses and pitting corrosion occurs. As a result, this pitting corrosion progresses deep into the interior.

When pitting corrosion progresses in this way, there is a problem that liquid or gas inside the tube may enter the tube and the tube loses its function as a heat exchanger. From the above-mentioned point of view, the present invention involves brazing, for example, a plating sheet as a fin material made of a core material of aluminum and aluminum alloy clad with a waxy layer of aluminum alloy to a tube body made of aluminum and aluminum alloy. This was done in order to prevent pitting corrosion from occurring in the bodies to be brazed, such as the pipe body and fin core material, in a heat exchanger manufactured by brazing the brazing material in the plating sheet. , in weight percent, Si:
3-15%, Mg: 0.5-5.0%, Zn: 0.3-4.0%, Bi: 0.01-0.5%, Sn: 0.01-0.5%, Contains, if necessary, one or two of the following: ln: 0.02 to 0.3%, Ga: 0.02 to 0.3%, N and unavoidable impurities: the remainder, By constructing the aluminum alloy with a composition of It is characterized in that it exhibits good fluidity when applied.

Next, the reason why the composition of the alloy of the present invention is limited as described above will be explained.

'a} Si The Si component has the effect of lowering the melting point of the alloy and improving its fluidity, but if its content is less than 3%, the desired effect cannot be obtained; on the other hand, if it exceeds 15%, If it is contained, the fluidity will be lowered and the self-potential will be significantly higher, so the content was set at 3 to 15%.

[bl Mg The Mg component lowers the melting point when coexisting with Si,
In addition to making brazing easier and lowering the self-potential of the alloy, it also prevents the formation of local batteries of alloy components and prevents self-corrosion.
It has the effect of preventing the segregation of alloy components and creating a uniform structure, thereby preventing local preferential corrosion caused by segregation, but if its content is less than 0.5%, the desired effect cannot be obtained. On the other hand, if the content exceeds 5.0%, edge cracking will occur frequently in the rolling process during the production of the plating sheet, so the content was set at 0.5 to 5.0%.

'c} The BiBi component has the effect of increasing the fluidity of the alloy, lowering the self-potential, and promoting uniform corrosion, but if the content is less than 0.01, the desired effect may not be achieved. On the other hand, even if the content exceeds 0.5%, there is no further improvement effect due to the above-mentioned action, and it is not economical. Therefore, the content was determined to be 0.01 to 0.5%.

{d) The ZnZn component has the effect of lowering the natural potential of the alloy, but if its content is less than 0.3%, the desired natural lowering effect cannot be obtained; on the other hand, if the content exceeds 4.0%, Since further improvement effects cannot be expected even if the content is 0.3% to 4.0%.

{e'Sn The Sn component has the effect of reducing surface tension during brazing and improving fluidity in coexistence with Mg, Bi, and Zn, but if its content is less than 0.01%, the On the other hand, if the content exceeds 0.5%, Sn polarization will occur frequently during the solidification process, so the content should be adjusted to 0.01 to 0.5%.
It was set at 5%.

(f} ln and Ga ln and Ga have an equal effect of lowering the natural potential of the alloy, and are therefore components that are included when it is necessary to further lower the natural potential. If the content is less than 0.02%, the desired improvement effect cannot be obtained, while if the content exceeds 0.3%, self-corrosion will occur, so the content should be reduced to 0.02%. 0.3%, respectively.

Next, the alloy of the present invention will be specifically explained with reference to Examples.

Example 1 Conventional AI alloys 1 and 2 for brazing filler metals and the present invention for brazing filler metals having dimensions of 30 mm thickness x 100 mm width x 3000 mm length, and each having the composition shown in Table 1. Prepare coin blocks of Yamagokin 1 to 4, hold each of these coins at a temperature of 48,000 for 8 hours to soak them, and then shave both sides to a thickness of 26 mm on one side. The material is made into a proboscis, and then hot rolled at a temperature of 480 oo to make a thick plate with a thickness of 56 ribs, and the thick plate is further cut into dimensions of 56 ribs thick x 1000 width side x 3000 pieces long. A hot-rolled plate (hereinafter referred to as a hot-rolled plate for brazing filler metal) serving as a soldering plate for a plating sheet was manufactured using the following methods.

Table 1 On the other hand, a conventionally known AI alloy 1 for core material has dimensions of 30 mm thickness x 100 mm width x 3000 mm length, and the compositions shown in Table 2. -4 mirror coins are prepared, these coin coins are kept at a temperature of 60,000 for 8 hours and soaked, and then one side is made to have a thickness of 20 mm and both sides are made to have a thickness of 260 mm. Thick plates serving as core materials for plating sheets were prepared by the following methods.

Table 2 shows the above-mentioned core material AI alloys 1 to 4 prepared in this manner.
The hot-rolled plates for use in the construction industry are superimposed on the upper and lower surfaces of the thick plates in the combinations shown in Table 3, and in this state they are heated to a temperature of 4.
After hot rolling at 85o0 to make the plate thickness 6, then cold rolling to make the plate thickness 1 side, intermediate carcass purification was performed by holding at a temperature of 350q0 for 2 hours, and finally the plate thickness was reduced by cold rolling. By making it 0.2 skin, conventional A as a brazing material
Placing sheets 1 and 2 using I alloys 1 and 2 (hereinafter referred to as conventional plating sheets) and plating sheets using AI alloys 1 to 4 of the present invention as brazing materials (
Examples 1 to 7 (hereinafter referred to as the plating sheet of the present invention) were manufactured, respectively.

Table 3 shows that the conventional plating sheets 1 and 2 and the plating sheets 1 to 7 of the present invention obtained as a result were cut into a width of 25 mm and separately prepared with a purity of 99.5% for use as a fin material. It has a composition consisting of the above pure AI (equivalent to AA standard 105), and has a width of 25 sides x thickness of 6 skin x
Combined with an extruded AI alloy deformed tube with a wall thickness of 1, this combination was heated to a temperature of 600°C in an N2 gas atmosphere.
By applying brazing treatment to 00 for 5 minutes,
The fin material 1 and the tube body 2 shown in a schematic perspective view in FIG.
A heat exchanger consisting of the following was manufactured.

Next, each of the resulting heat exchangers was subjected to a salt spray test for 300 hours, and the maximum depth of pitting corrosion occurring in the tube body 2 was measured.

The measurement results are also shown in Table 3. As shown in Table 3, the heat exchanger incorporating the fin material manufactured from the plating sheet of the present invention using the N alloy of the present invention as the brazing material is different from that of the conventional plating sheet using the N alloy of the present invention as the brazing material. The N alloy of the present invention, which exhibits significantly superior corrosion resistance, that is, pitting corrosion resistance, as compared to a heat exchanger manufactured using a heat exchanger sheet as a fin material, and in particular contains either ln and ○a, or both, as a fin material. It is clear that when used, even better pitting corrosion resistance is exhibited.

Example 2 A core alloy ingot with dimensions of 30 mm thick x 100 mm wide x 3000 mm long and a composition of AI-1.0% Mn (equivalent to AA3003) was prepared. After holding this mirror block at a temperature of 60q C for 24 hours and soaking it,
One side is machined on both sides by 20 sides to make a plank with a thickness of 260 ribs, and then on this one side, each side has a thickness of 56 sides and a width of 100 mm.
Thick plates of conventional N alloys 1 and 2 for brazing filler metals and river alloys 1 to 7 of the present invention for brazing filler metals having dimensions of length x 300 ratio and having the composition shown in Table 1, On the other hand,
Same dimensions and AI-1.0%Zn (AA7072
Thick plates having the composition (equivalent) were stacked one on top of the other, hot rolled at a temperature of 480 qC in this state to a thickness of 6, then cold rolled to a thickness of 1, and then rolled to a thickness of 35 qC.
By performing intermediate sintering at 0°C for 2 hours and then cold rolling to a thickness of 0.5, the plating sheet (using conventional AI alloys 1 and 2 as brazing filler metals) is produced.
A plating sheet using AI alloys 1 to 7 of the present invention (hereinafter referred to as a plating sheet of the present invention) was manufactured, respectively.

Next, the resulting plasing sheet is cut out to a width of 25 mm to be used as a tube, bent in the width direction, the mating surfaces are joined with sash stitching, and then rolled. By making it a flat tube with a width of 2,
Pipe bodies made from conventional plating sheets (hereinafter referred to as conventional pipe bodies) 1 and 2, both of which have brazing metal on the outside.
and a tube made from the plating sheet of the present invention (
Samples 1 to 6 (hereinafter referred to as the tube of the present invention) were manufactured, respectively.

Next, the conventional pipe bodies 1 and 2 and the pipe bodies 1 to 6 of the present invention obtained as a result of this process were made to have the compositions shown in Table 4, and have dimensions of 2 mm wide x 0.2 mm thick. By combining the obtained AI and N alloy fin materials and brazing this combination under the same conditions as in Example 1, the fin material 1 and tube body 2 shown in a schematic front view in FIG. A heat exchanger consisting of , and tank 3 was manufactured. Each of the heat exchangers was subjected to a salt spray test for 300 field hours, and the maximum depth of pitting corrosion occurring in the tube body 2 was measured.

The measurement results are also shown in Table 4. Table 4 As shown in Table 4, compared to the conventional pipe made from the conventional plating sheet using the conventional AI alloy as the brazing material, the pipe of the present invention using the needle alloy of the present invention as the brazing material It is clear that the tube of the present invention made from the ging sheet has significantly better corrosion resistance.

As mentioned above, since the alloy of the present invention has an extremely low self-potential, when used as a wax for plating sheets, corrosion caused by the core material and other product structural components is greatly reduced. Furthermore, it has excellent melt flowability (fluidity), so it has industrial properties such as being able to perform clean brazing work and using a small amount of brazing filler metal.

[Brief explanation of drawings]

FIG. 1 is a schematic perspective view of a heat exchanger, and FIG. 2 is a schematic front view of another heat exchanger. In the drawing, 1...Fi material, 2...
Pipe body, 3...tank. Younger brother's figure 2

Claims (1)

[Claims] 1 Si: 3-15% Mg: 0.5-5.0%, Zn: 0.3-4.0%, Bi: 0.01-0.5%, Sn: 0. 01 to 0.5%, Al and unavoidable impurities: the rest (more than % by weight), and is characterized by having a low self-potential and exhibiting good fluidity during brazing. Aluminum alloy for sheet brazing filler metal. 2 Si: 3-15%, Mg: 0.5-5.0%, Zn: 0.3-4.0%, Bi: 0.01-0.5%, Sn: 0.01-0.5 %, and further contains one or two of In: 0.02 to 0.3%, Ga: 0.02 to 0.3%, Al and unavoidable impurities: the remainder, (or more) % by weight), has a low self-potential, and exhibits good fluidity during brazing.