DE3012009C2 - Use of an AlMnSi alloy - Google Patents

Description

30th

The invention relates to the use of an AlMnSi alloy for the production of semi-finished products and finished parts for ^{conductive purposes, which must have a tensile strength of at least 120 N / mm 2} and an electrical conductivity of at least 29 m / Ω mm ² .

The standardized E-Al and E-Al-Mg-Si standard materials are used in Germany for guidance purposes. In the F 16 state according to DIN 40 501, E-Al has a very high electrical conductivity of at least 34.5 m / Ω mm ² for aluminum materials, but on the other hand it has only a very low strength. By strong work hardening can be in this material, although tensile strength of about 180 N / mm ² (in the state F 17 according to DIN 40 501) reach, however, this strength can actually be exploited to a maximum of 8O ⁰ C only in a range of temperatures because at higher Temperatures, depending on the duration of exposure, a softening to the completely soft state must be expected. For this reason, the area of application for E-Al in overhead lines is restricted to a limit temperature of at most 80 ° C, for example.

With the second common material, E-Al-Mg-Si, minimum tensile strength ^{values of 215 N / mm 2} can be achieved through hardening, but at the same time the electrical conductivity is reduced to a minimum value of 30 m / Ω mm ² . But even with this material is by prolonged heating at temperatures above 8O ⁰ C the risk bo a gradual softening by aging, the tensile strength may decrease in the fully soft condition up to 100 N / mm ^2.

Furthermore, it must be taken into account that an application limit temperature for a material also means that during the production and further processing of objects made from it, care must be taken that the limit temperature is not exceeded. So it is for example the case of materials with a threshold temperature of 8O ⁰ C is not possible to apply a Kunststoffisoüerung whose processing requires higher temperatures Further, it is not possible to enamel such materials or ay solder.

This results in the task of providing an aluminum material that is comparable to the known materials in terms of tensile strength and electrical conductivity, but in which these properties are reversibly retained up to a significantly higher application temperature. So do not improve the tensile strength and the electric conductivity as such, but the provision is aimed primarily of an aluminum material having similar minimum values, whose processing and application is not as restricted in the known materials to temperatures no higher than 8O ⁰ C.

To solve this problem, the invention proposes an AlMnSi alloy with 0.2 to 2% manganese, 0.6 to 3% silicon, 0.2 to 1% iron, 0 to 0.2% copper, 0 to 0.2 % Magnesium, the remainder aluminum, including a total of at most 0.2% unavoidable production-related impurities, whereby ^{semi-finished products or finished parts are produced from a cast block after the usual annealing at 400 to 620 0} C by hot and / or cold forming and these finally at 300 to 450 ⁰ C of an annealing until complete recrystallization are subjected.

Such semi-finished products or finished parts have a tensile strength of at least 120 N / mm ² and an electrical conductivity of at least 29 m / Ω mm ² , these minimum values being reversibly retained in the application range up to 450 ^{° C.} The semi-finished or finished parts are in a thermodynamically stable state so that the adjusted strength and conductivity values with security retained reversible even at a temperature stress above 8O ⁰ C, at least up to the respectively applied temperature recrystallization annealing.

If, during the use of the alloy in an optimum conductivity values, the recrystallization annealing is preferably carried out at about 300 ⁰ C. However, if optimum strength values are important when using the alloy, recrystallization annealing is expediently carried out at around 450 ° C.

AIMn alloys are known from D. Altenpohl, Aluminum and Aluminum Alloys (1965), pp. 685 to 699, which in the recrystallized state have a tensile strength of 90 to 110 N / mm ² and an electrical conductivity of 23 to 25 m / Ω mm ² have. These alloys obviously do not meet the requirements set here. From the same reference, AIMn alloys is further known to be subjected to a final recrystallization annealing after the ingot has been annealed as usual before the hot forging at about 600 ⁰ C before.

From the Aluminum Taschenbuch (1974), p. 953, there is a wrought aluminum alloy under the designation D 3005 known to contain 0.6% silicon, 0.7% iron, 0.2% copper, 1 to 1.5% manganese, 0.2 to 0.5% magnesium and Contains aluminum as the remainder. This alloy roughly corresponds to that to be used according to the invention, without that in this publication more information about their

Properties and areas of application are mentioned.

Finally, an overview of processes in the Structure and atomic arrangement became known in the course of the most important stages in the manufacture of semi-finished rolled products (see table in the appendix), from which the sequence of procedural steps can be derived the composition of the alloy to be used according to the invention must be observed. It deals However, it is only a general overview, without specific reference to a specific alloy or the Achieving certain properties.

With the aid of the diagram shown in the figure, further details and advantages are described which result from the use of the AlMnSi alloy according to the invention, taking into account the manufacturing measures. The diagram shows the tensile strength and conductivity values measured at room temperature, which result after two hours of recrystallization annealing at the temperature used in each case. In the work-hardened state, the material has a tensile strength of approximately 250 N / mm ² with an electrical conductivity of just under 30 m / Ω mm ² . With these values, the material to be used according to the invention is absolutely comparable with E-Al-Mg-Si in the hardened state. After recrystallization annealing at 300 ^° C., the tensile strength drops to the specified minimum value of 120 N / mm ² , while the electrical conductivity increases to 30.7 m / Ω mm ² . With a recrystallization annealing from 300 to 500 ° C, the tensile strength increases steadily to over 160 N / mm ² , while the electrical conductivity also drops almost continuously to below 28 m / Ω mm ^2. The temperature range that can be used for the recrystallization annealing under the given conditions is therefore expediently limited to an upper limit of 450 ° C. in order to avoid an excessive decrease in the electrical conductivity. At this annealing temperature, the conductivity is just under 29 m / Ω mm ² , while the tensile strength has already risen ^{to over Ϊ40 N / mm 2} and electrical conductivity can be adjusted. It should be repeated once more that the properties set in this way are reversibly retained regardless of the temperature at which the semi-finished products or finished parts are used, because the material structure is in a thermodynamically stable state

The diagram also shows that the material can of course also be used without prior Recrystallization can be used when a particularly high tensile strength is important and when Use the room temperature is certainly not significantly exceeded. To that extent would the However, the material is subject to the same restrictive conditions as those mentioned at the beginning known materials.

With semi-finished products and finished parts that are used according to the invention, one is always on the safe side Page; the minimum values for strength and electrical properties that arise after complete recrystallization Conductivity are still guaranteed even if during processing such as applying a Insulation, enamelling, soldering etc. higher temperatures must be applied.

1 sheet of drawings

Claims (3)

1 claims: 1. Use of an AlMnSi alloy with 0.2 to 2% manganese, 0.6 to 3% silicon, 0.2 to 1% iron, 0 to G, 2% copper, 0 to 0.2% magnesium, the remainder being aluminum including a maximum of 0.2% unavoidable production-related impurities for the production of semi-finished products and finished parts for control purposes, which are produced from a cast block after the usual annealing at 400 to 620 ° C by hot and / or cold forming and finally at 300 to 450 ⁰ C are subjected to annealing up to complete recrystallization, have a tensile strength of at least 120 N / mm ² and an electrical conductivity of at least 29 m / Ω mm ² , with these minimum values in the application range up to 450 ⁰ C being reversible. 2. Use of an alloy according to claim 1, wherein the recrystallization annealing to achieve optimal conductivity values is carried out at about 300 ° C for the purpose of claim 1. 3. Use of an alloy according to claim 1, wherein the recrystallization annealing to achieve optimal strength values carried out at around 450 ° C for the purpose of claim 1. 20th