CZ296688B6 - Use of aluminium alloy - Google Patents

Abstract

The present invention relates to the use of an aluminium alloy containing more than 97 percent of aluminium in the alloy wherein the sum of alloying proportions of at the most 2 main alloy components exceeds the sum of the alloying proportions of the remaining alloying components by at least a factor of 5. The invented alloy finds its use in the manufacture of sheets to screen-off heat, particularly in motor vehicles.

Description

Area of techniques

The invention relates to the use of an aluminum alloy for the production of heat shielding sheets with an aluminum content in the alloy greater than 97%.

BACKGROUND OF THE INVENTION

Due to the physical properties of aluminum, in particular its high reflectivity in the infrared region and very good thermal conductivity, particularly advantageous for heat shielding, aluminum alloys have established themselves as a standard material for the production of heat shielding sheets.

In order to exploit these physical properties of aluminum to a large extent and to meet the high requirements for the formability of the material in sheet metal production to remove heat, about 80% of the aluminum heat shielding sheets from Al 99.5 aluminum (AA1050) are currently produced, is a common designation of an aluminum alloy containing at least 99.5% aluminum.

A sufficiently good formability of this material is ensured by deep drawing, since the ductility of aluminum Al 99.5 is about 45%.

Al 99.5 aluminum contains the following alloying components in addition to aluminum:

Alloy component upper limit silicon 0.25% copper 0.05% magnesium 0.05% zinc 0,07% manganese 0.05% titanium 0.05% other 0,03%

Although the use of Al 99.5 aluminum has been advantageous in terms of high heat shielding and good formability, it is also problematic in other respects.

Aluminum Al 99.5 has a particularly low strength. However, the use of heat shielding sheets in the construction of motor vehicles imposes high strength requirements, such as, for example, causing wind during driving and the impact of pebbles. The low strength of aluminum Al 99.5 leads to the fact that sheet metal extrusions of greater thickness must be used to provide the required strength, which both increases the cost and increases the weight of the sheet to shield heat.

The low thermal stability of Al 99.5 aluminum, in which the brittleness occurs already at temperatures above 150 ° C, leads to a delicate shape stability in use, which, however, is necessary to maintain heat shielding with respect to the metal sheet. heat.

Aluminum Al 99.5 exhibits good deep ductility, as mentioned above, with a high ductility value.

-1 CZ 296688 B6

However, the yield strength is relatively low at about 30 N / mm ² . The low yield strength of aluminum Al 99.5 limits the possibility of forming in the production of heat shielding sheets.

A further problem, especially in the long-term use of heat shielding sheets, is that Al 99.5 aluminum has a strong tendency to form coarse grains, especially after slight cold forming. This formation of coarse grains, especially in the case of the unavoidable heat load of the sheets to shield the heat, leads to the risk of cracks, especially at the bends, for example at the places where the sheets are attached to the heat shield.

Also, the dynamic load values of the aluminum heat shielding plates of aluminum 99.5 are insufficient due to the strong coarse grain formation. The use of galvanized sheets, which in itself is desirable for structural reasons, is problematic when using Al 99.5 aluminum since shape stability cannot be ensured. This dimensional stability is deteriorated by the fact that in the case of tinplate sheets, increased coarse grain formation after thermal loading must be expected in the deformed tinplate regions.

SUMMARY OF THE INVENTION

Based on the above-described prior art, the present invention is based on the object of developing an aluminum alloy having improved formability, improved strength, higher thermal stability and less coarse grain formation compared to Al 99.5 aluminum.

According to the invention, this object has been achieved by using an aluminum alloy with an aluminum content in alloys of greater than 97%, the sum of the contents of at most two alloying constituents in the alloy being at least five times the sum of the remaining alloying constituents in the alloy. heat for motor vehicles.

The sum of the contents of at most two main alloying components in the alloy preferably is at least ten times the sum of the contents of the remaining alloying components in the alloy.

The main alloying components are preferably iron and manganese.

The manganese content of the alloy is preferably from 0.35 to 0.45% by weight.

In a preferred embodiment, one major alloying component is iron.

The iron content of the alloy is preferably from 1.25 to 1.35% by weight.

The aluminum content of the alloy is preferably at least 98% by weight.

The silicon content of the alloy is preferably at most 0.2% by weight.

The magnesium content of the alloy is preferably at most 0.03% by weight.

The zinc content of the alloy is preferably at most 0.03% by weight.

The titanium content of the alloy is preferably at most 0.03% by weight.

The chromium content of the alloy is preferably at most 0.02% by weight.

It follows from the above that the sum of the contents of at most two main alloying components is at least five times the sum of the contents of the remaining alloying components. Through the predominance of at most two alloying constituents, permissible in aluminum Al 99.5 over the remaining alloying constituents, it is ensured that the aluminum alloy has a significantly more homogeneous structure, thereby

-2GB 296688 B6 improves strength and ductility, while reducing the tendency to coarse grain formation. The ductility remains at least at the same level.

Doubling of the yield strength is also ensured, while at the same time increasing the strength by at least 50% by the sum of the contents of the main alloying components at least ten times the sum of the contents of the remaining alloying components.

An aluminum alloy with a particularly high yield strength and good tensile strength unchanged against Al 99.5 aluminum is characterized in that the main alloying components are iron and manganese.

The optimization of the yield strength and strength of the aluminum alloy is ensured by the manganese content in the alloy being from 0.35 to 0.45%.

The aluminum alloy, when the only major alloying component is iron, exhibits an improved yield strength and strength while improving ductility over Al 99.5 aluminum.

The properties of the aluminum alloy are ensured both when the main gelling constituents are iron and manganese and when the only main alloying constituent is iron, by ensuring that the iron content of the alloy is from 1.25 to 1.35%.

In order to make the most of the advantageous physical properties of aluminum for heat shielding sheets, it is preferred that the aluminum content of the aluminum alloy is at least 98%.

By ensuring that the silicon content of the alloy does not exceed 0.2%, it is ensured that the desired increase in yield strength and strength with at least unchanged ductility and coarse grain formation is achieved. For the same reasons, it is preferred that the magnesium content of the alloy does not exceed 0.003% and / or the zinc content of the alloy does not exceed 0.03%.

Chromium and titanium, which are also acceptable for aluminum Al 99.5, do not initially deteriorate the desired properties of the aluminum alloy even above the permitted levels. However, to ensure the desired properties of the aluminum alloy, it is preferred that the titanium content of the alloy does not exceed 0.03% and / or the chromium content of the alloy does not exceed 0.02%.

The contents of copper, sodium and potassium as other alloying constituents acceptable in the alloy deteriorate the achieved properties only slightly.

DETAILED DESCRIPTION OF THE INVENTION

The yield strength, improved to about 100 N / mm ² , is ensured by the composition of the aluminum alloy with the alloying component contents acceptable for Al 99.5 aluminum within the following limits:

-3GB 296688 B6

Table 1

Alloy component lower limit upper limit silicon 0.05% 0.1% copper 0.0% 0.05% magnesium 0.0% 0.003% zinc 0.0% 0,03% bor 0.0% 0.002% sodium 0.0% 0.001% lithium 0.0% 0.0002% iron 1,25% 1.35% manganese 0.35% 0.45% chrome 0.0% 0.02% titanium 0.0% 0,03% beryllium 0.0% 0.0% potassium 0.0% 0.001%

Within the given limits, the contents of the alloy components can be specifically varied to adjust the various properties of the aluminum alloy.

The contents of the aluminum alloy components of the first exemplary embodiment having a yield strength of about 110 N / mm ² , a yield strength of 124 N / mm ^2, and an elongation of about 45% will be discussed below. The contents of the components in such an aluminum alloy are as follows:

Table 2

Alloy component content in alloy silicon 0,063% copper 0.005% magnesium 0.0016% zinc 0.0036% bor 0.001% sodium <0.001% iron 1,34% manganese 0, 37% chrome 0.0014% titanium 0.019%

The contents of the aluminum alloy of the second exemplary embodiment having a yield strength of about 66 N / mm ² , a strength of about 108 N / mm ^2, and an elongation of about 52% will be discussed below. The contents of the components in such an aluminum alloy are as follows:

-4GB 296688 B6

Table 3

Alloy component content in alloy silicon 0.08% copper 0.004% bitter k 0.0021% zinc 0.0044% bor 0.001% sodium <0.001% iron 1.3% manganese 0.014% chrome 0.0012% titanium 0.02%

PATENT CLAIMS

Use of an aluminum alloy with an aluminum content in the alloy greater than 97%, wherein the sum of the contents of at least two major alloying constituents in the alloy is at least five times the sum of the remaining alloying constituents in the alloy for producing heat shielding plates for motor vehicles.

Claims (12)

Use of an aluminum alloy with an aluminum content in the alloy greater than 97%, wherein the sum of the contents of at least two major alloying constituents in the alloy is at least five times the sum of the remaining alloying constituents in the alloy for producing heat shielding plates for motor vehicles. Use of an aluminum alloy according to claim 1, wherein the sum of the contents of at most two major alloying components in the alloy is at least ten times the sum of the contents of the remaining alloying components in the alloy. Use of an aluminum alloy according to claim 1 or 2, wherein the main alloying components are iron and manganese. Use of an aluminum alloy according to claim 3, wherein the manganese content of the alloy is from 0.35 to 0.45% by weight. Use of an aluminum alloy according to claim 1 or 2, wherein the only major alloying component is iron. Use of an aluminum alloy according to any one of claims 3 to 5, wherein the iron content of the alloy is from 1.25 to 1.35% by weight. Use of an aluminum alloy according to any one of claims 1 to 6, wherein the aluminum content of the alloy is at least 98% by weight. Use of an aluminum alloy according to any one of claims 1 to 7, wherein the silicon content of the alloy is at most 0.2% by weight. Use of an aluminum alloy according to any one of claims 1 to 8, wherein the magnesium content of the alloy is at most 0.003% by weight. Use of an aluminum alloy according to any one of claims 1 to 9, wherein the zinc content of the alloy is at most 0.03% by weight. Use of an aluminum alloy according to any one of claims 1 to 10, wherein the titanium content in the alloy is 5 at most 0.03% by weight. Use of an aluminum alloy according to any one of claims 1 to 11, wherein the chromium content of the alloy is at most 0.02% by weight.