JPS6038455B2 - High strength aluminum alloy with good brazing properties - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an aluminum alloy that has excellent brazing properties and maintains excellent corrosion resistance and high strength even after brazing treatment.

Generally speaking, JISA 3003 alloy (AI-1.0%Mn) and A3004 alloy (AI -1
．． 0%Mn-1.0%Mg) thin plate is used, and its assembly is done by directly soldering the thin plate in a predetermined shape, or by directly soldering the thin plate in a predetermined shape,
Alternatively, the thin plate is used in a state where it is paper-bound with a plating sheet, or a plating sheet is formed by cladding wax on both sides of the thin plate, and this is heated in a heating furnace to a temperature of 580 to 63,000. This is done by soldering. However, the above 3003
Although alloys have excellent brazing properties and exhibit relatively good corrosion resistance even after brazing, the strength of the alloy decreases due to heating during brazing. When used in the manufacture of heat exchangers that are subjected to external stress such as, there are problems such as damage.

Furthermore, although the 3004 alloy has high strength even after brazing, its brazing properties are extremely poor.
Corrosion resistance was also not good.

This invention provides an aluminum alloy that has excellent brazing properties and also has high strength and excellent corrosion resistance even after brazing treatment, based on the above-mentioned points. :0.4-2.0%, V:
0.01-0.5%, further containing as necessary, Cu: 0.1-0.8%, Mg: 0.1-0.6%, Zr: 0.01-0.4 It is characterized by an aluminum alloy having a composition containing one or more of the following: %, and the remainder: mountains and unavoidable impurities.

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

'a} The MnMn component has the effect of increasing the corrosion resistance and strength of the alloy, but if the content is less than 0.4%, the desired effect cannot be obtained; on the other hand, if the content exceeds 2.0%, Since no further improvement effect was observed even if it was added, the content was set at 0.4 to 2.0%.

'b) V The V component has the effect of improving brazing properties, preventing a decrease in strength of the alloy after brazing, and improving corrosion resistance, but if its content is less than 0.01%, the above-mentioned The desired effect cannot be obtained, and if the content exceeds 0.5%, coarse crystals of the V compound, which has an adverse effect, are likely to occur, so the content should be reduced to 0.01 to 0.5%.
It was determined that

'c} Cu, Mg, Zr These components have an even effect to further improve the strength of the alloy, but Cu: less than 0.1%,
If Mg: less than 0.1% and Zr: 0.01%, the desired effects cannot be obtained, so it is necessary for each component to be contained at the lower limit value or more.

However, if the Cu content exceeds 0.8%, Cu segregation tends to occur, and moreover, the uneven parts of Cu melt locally during brazing, resulting in a decrease in strength at the brazing temperature. As for the Mg component,
If the Zr content exceeds 0.6%, the brazing properties will deteriorate and the corrosion resistance after brazing will decrease, and if the Zr content exceeds 0.4%, the Zr content will be even worse. Since no improvement effect was observed, the upper limits of the components were set to Cu: 0.8%, Mg: 0.6%,
Zr: was set at 0.4%. Next, the alloy of the present invention will be explained using examples while comparing it with a conventional alloy.

First, by using the normal melting and casting method, a length of 250 mm x width of 1 mm was created.
Alloys 1 to 8 of the present invention, each having dimensions of 0.00 yen x 45 yen thickness, and each having the composition shown in Table 1.
, manufactured mirror blocks of conventional alloy 1 (equivalent to JISA3003 alloy) and conventional alloy 2 (equivalent to JISA A3004 alloy), and then subjected to soaking treatment at a temperature of 600 oo for two unique intervals, and then placed on both sides on the 25 side. The sintered anchor was scraped off, reheated to a temperature of 520°C, hot rolled to a thickness of 6, then cold rolled to a thickness of 1.2, and kept at a temperature of 400 oo for 1 hour. In this way, thin alloy sheets 1 to 8 of the present invention and conventional alloy thin sheets 1 and 2 were manufactured, respectively.

Next, from the resulting thin alloy sheets 1 to 8 of the present invention and conventional alloy thin sheets 1 and 2, a length of 20 mounds x width of 15 mounds x
A test piece 1 with dimensions of 1.2 ribs in thickness was cut out, and a separately prepared plating sheet 2 with dimensions of 20 W in length x 80 ribs in width x 1.2 in thickness was cut out, as shown in perspective in Figure 1. assembled in the form shown in the figure and brazed by holding at a temperature of 600° C. for 15 minutes in a vacuum of 10-5 torr;
A tensile test piece (JIS No. 5 test piece) was cut out from the test piece 1 after brazing, and a tensile test was conducted.

The test results are shown in Table 1. Table 1 As is clear from the results shown in Table 1, conventional alloy 1
, the strength (tensile strength and yield strength) decreases due to brazing treatment, whereas in the present invention alloys 1 to 8, no decrease in strength is observed even after brazing treatment, similar to conventional alloy 2. .

In addition, Table 2 uses a corrosion test piece (dimensions: length 15 mm x width 7 mm x thickness 1.2 mm) cut out from test piece 1 after brazing, and conforms to JIS Z2371. Based on the salt water spray test in which salt water is sprayed for 1 month, and in tap water for 10 days.
A tap water immersion test was conducted with 0 field immersion time, and the results of observing the corrosion status after the test are shown.

As shown in Table 2, it is clear that all of the alloys 1 to 8 of the present invention have excellent pitting corrosion resistance comparable to conventional alloys 1 and 2.

Note that conventional alloy 2 suffered from significant intergranular corrosion and did not have good corrosion resistance. Furthermore, Fig. 2 a and b
As shown in the side view in FIG. The flow state of the wax 2b before brazing (see Fig. 2a) and after brazing under the condition of holding the temperature at 60,000 for 5 minutes (see Fig. 2b), that is, the wax 2b before brazing on the plating sheet 2. The cross-sectional area Ao of the fillet 3 and the cross-sectional area A of the fillet 3 formed after brazing were observed, and the ratio A/Ao (this ratio is referred to as the fluidity coefficient F) was calculated.

This flow coefficient F serves as a guideline for bondability,
The closer F is to 1, the better the fluidity of the wax is, and the better the fillet 3 is formed. As a result, the alloy 5 of the present invention and the conventional alloy 1 were each 0.0.
60 and 0.62, and brazing is performed well, whereas conventional alloy 2 shows flow coefficients of 0.60 and 0.62.
It exhibited a flow coefficient of only 12, indicating difficulty in brazing. Table 2 As shown, although conventional alloy 1 has excellent brazing properties and corrosion resistance, it has the problem of low strength after brazing, and conventional alloy 2 has high strength after brazing. However, it has the problem of extremely poor brazing properties and intergranular corrosion resistance.

In contrast, the alloy of the present invention exhibits excellent brazing properties and also has excellent corrosion resistance and high strength even after brazing. Example 2 Each has the component composition shown in Table 1, and has a length of 2
Yamaichi 9.5% Si-1.5% was applied to the upper and lower surfaces of mirror ingots of the present invention alloy 5, conventional alloy 1, and conventional alloy 2, which had dimensions of 50 mm x width of 100 mm x thickness of 450 mm. It has a composition of Mg (wt%), length 250 x width 100 x thickness 55
Layer wax materials with side dimensions and heat to 500o.
Hot rolling was carried out at 6. A pressing sheet having a core made of the alloy 5 of the present invention was obtained by cold rolling it to a thickness of 1.2 and then sintering it at a temperature of 400°C for 1 hour. A pressing sheet with a core made of conventional alloy 1 and a pressing sheet with a core made of conventional alloy 2 were manufactured, respectively.

Next, from the three types of praising sheets obtained as a result, test pieces 4 having the dimensions of 7 m long x 3 m wide x 12 m thick were cut out, and a separately prepared test piece 4 of length 7 m was cut out. A thin plate piece 5 made of JISA 3003 alloy (corresponding to the conventional alloy 1 described above) having the dimensions of the proboscis x width of 50 ribs x thickness of 1.2 ribs is assembled into the shape shown in the perspective view in Fig. 3, The flow coefficient is measured by brazing at a temperature of 600 oo for 5 minutes, and separately at a temperature of 600 oo.
Brazing was performed at 10:00 AM under conditions of holding for 5 minutes, and the depth of solder melting was measured. In addition, wax penetration depth d
As shown in the side view in FIG. 4, if the thickness of the core of the plating sheet is t, and the minimum thickness of the core at the brazing part (fillet forming part) is d, then d=
It is expressed as t-chi/2, and the larger the value of d, the more significant the corrosion of the wax is. The results of these measurements are shown in Table 3. Table 3 As shown in Table 3, in the measurement of the flow coefficient of the wax, as in Example 1, the present alloy 5 and the conventional alloy 1 were
In contrast, conventional alloy 2 has an extremely low flow coefficient of solder, indicating that good brazing cannot be expected.

Furthermore, when measuring the penetration depth of the solder, almost no corrosion was observed in the present invention alloy 5 and the conventional alloy 1, and good brazing was possible, whereas in the conventional alloy 2, the solder was completely absorbed. It was impossible to penetrate and form a sound brazed joint.

As mentioned above, the alloy of the present invention has excellent brazing properties and maintains excellent corrosion resistance and high strength even after brazing treatment, so it can be used, for example, in a radiator header plate. The thickness of the slope can be made thinner than that of the conventionally used A3003 alloy, making it easier to process and lighter in weight. When used in place of the A3003 alloy, it brings about industrially useful effects such as resolving the conventional concerns about strength.

[Brief explanation of the drawing]

Figures 1 and 3 are perspective views showing the assembled state of the brazing test piece, and Figure 2 is a side view showing the assembled state of the brazing test piece. 4 shows the state after brazing, and FIG. 4 is a side view showing the state after the brazing test. In the drawings, 1, 5... test piece, 2, 4...
...Praising sheet, 2a...Core, 2b...
Ro, 3... Fillet. groove? Figure 2 Figure 3 Figure 4

Claims (1)

[Scope of Claims] 1 Mn: 0.4 to 2.0%, V: 0.01 to 0.5%, Al and unavoidable impurities: the remainder (more than % by weight). High strength aluminum alloy with good brazing properties. 2 Contains Mn: 0.4-2.0%, V: 0.01%-0.5%, and further contains Cu: 0.1-0.8%, Mg: 0.1-0.6 %, Zr: 0.1 to 0.4%, and one or more of the following: Al and unavoidable impurities: the remainder: (more than % by weight). High-strength aluminum alloy with good adhesion properties.