DE2034838A1 - Process for improving the compressibility of aluminum alloys of the type AlMgSi - Google Patents

Description

VAW Leichtmetall-Werke GmbH
Bonn

Process for improving compressibility of aluminum alloys of the type AlMgSi

-It is known that by adding boron the surface, of extruded semi-finished products that are subjected to a chemical and / or electrolytic treatment, one of structural markings resulting streaky surface largely can be avoided. Here in particular the one in increasing Dimensions of the extruded material used in architecture AlMgSi 0.5, which is almost always in an anodized state is used. Undoubtedly the beneficial effect of a boron additive is to explain the anodisability by influencing the casting, primarily through grain refinement.

It has now surprisingly been found that a normal grain refinement / Efexceeding addition of boron to this material not only has a favorable effect on the appearance of the surface after anodizing, but also in addition the compression properties of this material are considerably improved. The latter was only the case when after the addition of boron an intensive treatment with a gaseous one Medium was preferably carried out with chlorine, argon or nitrogen, and if the ingot is one known per se Were subjected to homogenization treatment. If such fumigation is not carried out, the addition of boron alone no improvement in the compression properties is achieved » if, on the other hand, a treatment with chlorine, nitrogen or argon is applied without the addition of boron, then a certain amount occurs Improvement of the compressibility compared to the material not treated with a gaseous medium, but becomes the optimum compressibility, as found with a combination of boron addition and fumigation, is not achieved in all cases homogenization to improve compressibility indispensable.

109884/0806 - 2 -.

BAD ORIQJNAL

For materials of the type AlMgSi with higher Mg or Si contents, For example, with the materials AlMgSi 0.8 and AlMgSi 1 according to standard sheet DIN 1725, sheet 1, the same As in the case of the AlMgSi 0.5 material mentioned at the beginning, a significant improvement in the compression properties found by the method described.

An addition of titanium, as it is generally used because of its grain-refining properties Effect in extrusion alloys of the type AlMgSi is common, is not only unnecessary with the proposed method, but disadvantageous. The introduction of boron can be in the form of boron-containing chemical compounds, for example Potassium boron fluoride and borax, or as an aluminum-boron master alloy.

A pplication for games

Example 1)

(Influence of fumigation when adding boron to AlMgSi 0.5) A casting batch with the following chemical composition: ($)

Cu 0.018

Mn 0.025

Mg 0.52

Si 0.45

Fe 0.20

Zn 0.050

Ti 0.005
Remainder aluminum

was in the furnace $ 0.03 boron in the form of potassium boron fluoride added. The contents of the furnace were placed in a heatable crucible furnace decanted. After that, the melt is cleaned in the usual way a part of it became round rods with 145 mm poured off »The rest of the batch is then reduced to 1 kg Clp / t chlorinated and poured off in the same way. All the material was homogenized for 12 Ii at 560-570 ° C. »Comparative press = try to show the following result §

Hohlp ^ ofil-, l'JanMiek © "1 * 2 ram * PreSgesGtoinöigkeit 35 m / min» Bie e-Uloriert © n barges could be pressed with 35 ra / min »

BATH ORIGINAL

The non-chlorinated bars exhibited at this press rate slight flaking. The pressing speed therefore had to be reduced to 27 m / min.

Example 2)

(Influence of adding boron to AlMgSi 0.5 when gassing with chlorine or argon)

5 batches each (έ approx. 4.5 t) cast ingots made of AlMgSi 0.5 / chemical composition according to DIN 1725> sheet 1, but with an addition of boron in the form of KBFj. from

0 0.005 0.01 0.02 and 0.03 # were treated with 0.7 kg of Cl _? / t or t treated with 0.35 kg Ar / 12 h at 560 - 570 ⁰ C is homogenized and compressed into a thin-walled hollow profile.

At a pressing speed of 35 m / min and a bolt temperature From 480 ° oj, very light flakes appeared for the first time after the following number of pressings;

Number of pressings up to the first appearance of slight flaking during treatment

Boron addition % with chlorine with argon 0 3 2

0.005 4 3

0.01 6 4

0.02 6 5

0.03> io 7

Example 3)

(Influence of adding boron to AlMgSi 0.8 when gassing with chlorine)

Tubes with dimensions of 60 χ 2 mm made of AlMgSi 0.8 with the following chemical composition

- 4 -10988470606

. BATH ORIGINAL

Cu 0.024

Mn 0.060

Mg 0.80

Si 0.75

Fe 0.22

Zn 0.03

Ti 0.007

B 0.007 (dated 0.03 %)

were produced in such a way that 0.03 $ boron was added in the form of potassium borofluoride in the furnace. The melt was then chlorinated with 0.7 kg Cl / t and homogenized at 560 ° -570 ° C. for 12 h. In a pin temperature of 530 - 54o ° C and an outlet temperature of 520 ⁰ C the tubes by means of fans over a period of 70 to 200 ⁰ C were lake blown off. After a heat treatment of 3 hours at 195 ° C, the following mechanical properties were found:

O ₀₂ = 27 kgf / mm ²

er _B '= 30.2 "

O ₅ 15 %>

In the case of material not treated with boron but also chlorinated and of practically the same composition, a pressing speed of more than 10 m / min could not be maintained without the appearance of flakes on the pipe surface Fan current to achieve the required temperature of at least 510 ^{0 C «}

Example 4)

(Influence of the addition of boron on AlMgSi 1 and the homogenization when gassing with chlorine)

Bars in AlMgSi 1, 145 mm 0, with the following chemical composition: {%)%

Cu 0.048

Mn 0.71

Mg 1.03

Si 1.02

Pe 0.37

Zn 0.15

Ti 0.010

B 0.020 (added $ 0.03 in the form of

109884/0806

were homogenized for 12 h at 480 C and pressed to form a hollow profile with a wall thickness of 2 mm. As a result of the addition of boron, the pressing speed was increased from 3r5 to ^ r> m / min compared to a similar, ie chlorinated, casting, but without the addition of boron. Upon entry of the profile in a mounted in the outlet of the profiles standing water wave measured at the profile temperature 52o ° C was at a billet temperature of 5 ² IO ⁰ C. The temperature of 520 G completely sufficient to h after an artificial aging of 12 at 170 ⁰ C to achieve the following strength values:

° q _{) 2} = 26.6 -30.5 kp / mm ²

O ₅ = 13-14.4 %.

Was not homogenized with the same composition and fumigation, so were because of the too low pressing speed of approx. 2 m / min no sufficient values found:

6 ~ 0.2 = 18.3-25.2 kgf / mm ²

Qj ₃ '= 22.7 - 27.3 "

O ₅ = 11-19.4 %.

Example 5)

(Influence of an addition of boron as an AIB master alloy in Fumigation and chlorination) A test batch of the type AlMgSi 0.5 with the following chemical ■ composition (#):

Cu 0.046

Mn 0.028

Mg 0.58

Si 0.43

Pe 0.22

Zn 0.050

Ti 0.005

0.03 ^ boron was added in the form of a 3 ^ AIB master alloy. The ingots were homogenized 12 hours at 560 ° C and pressed at a billet temperature of 470 ⁰ C. With an angle profile of 2 mm wall thickness, a pressing speed of 110 m / min was achieved. Although the outlet temperature increased in this extremely high press speed on the profile to 530 ⁰ C, the profiles showed a clean smooth surface.

': - 6 10-9834 / 0606'

Claims (4)

In contrast, the pressing speed was at. a comparative batch having the following composition (to which no metallic boron was added) (%); Cu 0.038 Mn 0.026 Mg 0.52 Si 0. ^ Q Fe 0.20 Zn 0.045 Ti 0.005 with the same profile only 30 m / min ,, patent 1) Process for improving the compression properties of billets of the genus AlMgSi., marked by dadurßh, / ^ C ^ ^ f ve that an amount of boron which goes beyond the normal purpose of use is added to the melt and then the melt is gassed, for example with chlorine, argon or nitrogen, and homogenization takes place. 2) Method according to claim 1), characterized in that that boron in the form of a boron-containing chemical compound, for example as potassium borofluoride or as borax or in Form of an AIB master alloy is added. 3) Method according to claim 1) and 2), characterized in that the material of the type AlMgSi has the following chemical composition {%)% Cu 0 - O ₅ 20 Mg 0.30 - 1.50 Si 0 * 30 - 1 * 50 Fe 0.10-0.40 Zn 0.01-0.30 Ti 0.001-0.020 B 0.005-0.03 Bo? Additional Oj, 01 - 0.05 ^ ₅ preferably 0/03 $ - 7-109 884/080 $ 4) Method according to claim 1 to 3, characterized in that that the billets are subjected to homogenization for 2 to 24 hours at 480 to 600.degree. C. before pressing. 109884/0806