NL7905547A - METHOD FOR ADDING METALLIC ALLOYS TO A BATH OF MOLLED ALUMINUM, SUCH ALLOYS, AND ALUMINUM ALLOYED ALLOY. - Google Patents

Description

AL 30 v v * 4 * "ALUmrJK DELFZIJL B.V« in Delfzijl

ADDITION FOR HIS ADDITION TO ALLIQUE LEGSRIKGSECBDELEÏÏ AAH EE; T BAD GE3Ï-I0LTEIT ΑΠΤίΙΗΙϋΙί, SUCH AN ARMY MEMBERSHIP SIT, AND THE ALTIAFINUKLE'GERLI GETTED

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The applicant mentions as inventor:

Ir Gijsbert Willem Meindert VA2T WIJK in Delfzijl

The invention relates to a new method of adding metallic alloying agents to a bath of molten aluminum. The invention relates to the alloying agents used and to the aluminum alloy obtained. -

In order to make aluminum more suitable for various operations, such as casting, kneading or rolling, or for various applications, such as as construction material, baking sheet material, for domestic applications, various elements such as alloy were added.

Known alloying elements are, for example, manganese, chromium, iron, boron, titanium and silicon. Often these elements are added as pure metal to the aluminum bath, or as an aluminum alloy. For special applications, for example for grain refining, aluminum alloys with a combination of titanium and boron are also occasionally used.

When alloying with these alloying agents, it is often important that they dissolve sufficiently quickly. Chromium, for example, does not dissolve quickly at high temperatures. For this reason, pre-alloys of the pure metals with aluminum are frequently used. Manganese dissolves too slowly at temperatures up to 75'3 ° C. At higher temperatures, for example 850 to 900 ° C, such as these occur in the transport pans that bring electrolysis metal to the foundry, manganese dissolves sufficiently quickly.

It is now common practice to fake prealloys through the pure 790 5 5 47 o. Add 2 'AL 30 alloy metal to high-heat liquid aluminum. Pure alloy metals are also used for direct alloying. This • involves significant costs. It is therefore the object of the invention to achieve cost savings in alloying.

It has now been found that according to the invention, especially in cases where is alloyed at a lower temperature (700 - 750 ° C), a considerable one; Cost savings can be obtained if not the pure alloy elements or their prealloys with aluminum are used, but that the alloying agents consist at least in part of aluminum alloys and ferroalloys of the desired alloying agents.

; As is known, it is often already desirable in the alloying of aluminum with elements such as manganese, chromium, silicon and boron that these; alloying elements in combination with iron are added. Up to now ; however, no use was made of the possibility of producing manganese aluminum and ferroalloys from these elements; use chromium, boron or silicon. However, these ferroalloys are considerably cheaper than the elements themselves.

:. It must be assumed that against the use of such advantages! alloys as an alloying agent for aluminum have obvious prejudices; stood. For example, it can be assumed that the prejudice against ferroalloys consisted in the fact that they often contained sulfur, phosphorus and carbon; elements which are partly soluble in the aluminum, such as phosphorus, partly give rise to the formation of compounds which are undesirable in the aluminum. With the known modern metal cutting; handling techniques, such as vacuum techniques, filtration techniques, and the like, the elements sulfur, phosphorus and carbon no longer pose a major drawback, since both dissolved phosphorus and carbides and sulfides can be removed without much difficulty. Incidentally, in many cases it appears that the pre-alloys used are sufficiently pure and / or that these elements are not included in the molten bath, so that no special cleaning of the alloyed aluminum bath is necessary anymore.

; A prejudice that might exist with regard to it; use of ferroalloy alloys consists in that: their dissolution rate would be slower than that of several of the alloys; elements themselves. f 3

In practice, however, it has been found that this drawback hardly needs to occur, or that it can be easily remedied with additional measures according to the invention. For example, it is recommended to perform the alloying at a temperature that is not too low, and preferably at a temperature of about 900 ° C. Bit can be achieved by alloying the aluminum bath obtained by reduction in electrolysis cells in the transport pans immediately after tapping, which transports the bath to the foundry furnaces.

It is also recommended according to the invention to powder the ferrous alloy, or its pre-alloy with aluminum, before adding it to the bath. Although this increases the solubility, care must be taken that these fine particles do not remain on the bath due to the high surface tension, or the presence of an oxide skin on the bath and / or around the particles. To avoid these difficulties, it is possible according to the invention to blow the powdered alloying agent into the bath in a manner known per se. For this purpose, perfectly baking agents and constructions from metallurgy can be used to blow the powder under the bath surface using a lance, using just air or nitrogen as the floating medium. Another possibility is that the powdered alloying agent i is supplied in a manner known per se in the form of pellets, which lose their cohesion at the melting temperature.

It is noted that it is well known to shape alloy elements into such a pellet form, notably, this is a technique that has been proposed in the dosing of manganese to it; bath. However, it is a novelty to also apply this known technique in the metering of ferroalloys and / or aluminum prealloys of ferroalloys.

For the sake of completeness, it is stated mg that methods are known to increase the solubility of, for example, manganese in aluminum by j.

pre-skin the particles to be metered from a scut mixture which reduces the surface tension. Mountainous measures can also be applied to the use of ferrous alloys. ,

In addition to the method of adding alloying agents, the invention also relates to an alloying agent for aluminum.

minium itself, if it consists at least partly of a vocr alloy t

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[4 AL 30 '* • ί' ".

of ferroalloys of desired alloying elements, or a front alloy of these ferroalloys with aluminum.

Finally, the invention also relates to an aluminum alloy, if it has been obtained according to one of the methods described above. Although this does not exclude other alloys 5 ', four aluminum alloys with ferroalloys are described in the table below, which have been found to be successful in aluminum refining.

TABLE ".

AlMhSiFe Al ^ __ ^ 50 - 1ö $. S; i20 'è $ P®25 - 3l' 1 °:

AlPeSiCr Al ^ _ ^ Pe-) 5 _ ^ _ 3 ^ Cri5 ~ 3 $.

AlEeSi A13q _ 6o * £ Pe20 _ 10 ^ Si60 - 30 $ -

AlPeB Alg0 _ ^ Fe20 -5 <j0 B2 - 2>% [

Always smaller than 1 fo I.

It has also been found possible to use ferroalloys which are not pre-alloyed with aluminum and which correspond to the alloys with aluminum omitted in the table. However, it has been found that the aluminum prealloys can be dosed more accurately and are absorbed more quickly in the bath. Although it is possible to produce these aluminum pre-alloys by adding the iron alloys to molten aluminum, a method has also proved very well possible; * * Where aluminum is added during the production of the iron alloy. The possible savings which can be realized with the invention. are illustrated by the following example.

EXAMPLE 25

Alloying 1 ton of electrolysis metal (so-called E-metal) to an alloy with 1 Wt. $ Mn (AlLLri 1) means:

Si Fe I5n composition E-metal (wt. $) 0.25 0.53 1.10 remainder Al composition Al'Inl (wt. Fo) 0.04 0.12 0.002 remainder Al 30 (wt. $) . 0.21 0.41 1.1 in pounds per tonne melts 2.1 2.1 4.1 11/5 790 5 5 47

Claims (7)

A method for adding metallic alloying agents to a molten aluminum bath, characterized in that the alloying elements consist at least in part of prealloys of aluminum - 2 and ferroalloying of the desired alloying elements. * Method according to claim 1, characterized in that it is alloyed in a pan at about 200 ° C * Method according to claim 1 or 2, characterized in that the alloy is powdered before being fed to the healing bath. A method according to claim 3, characterized in that the powdered alloying agent is incorporated in a manner known per se. Bath is blown. x \. 790 55 47 / «fm> 6 'AL 30' <r * Method according to claim 4, characterized in that the powdery alloying agent is supplied in a manner known per se in the form of pellets, which lose their cohesion at the melting temperature. 5. al 30 i * The costs for the use of pure metals are (on filing date and approximate): 2.1 kg Si a ƒ 2.70 ƒ 5.67 4.1 kg Fe a ƒ 0.60 2.46 11 kg Kh a ƒ 2.50 27.50 total ƒ 35.63 per tonne of alloyed material The cost of using non-ferroaluminium alloys increases considerably. The cost of using ferro-silioo manganese (lm 70 $, Si 18 $ , Fè 8 $) and ferro manganese (Bin 75 $, Fe 20 $) are: 1 11.7 kg ferro-silico manganese a ƒ 1.10 ƒ 12.97 3.7 kg ferro manganese a ƒ Ο, δΟ 2, ^ 6 kg of iron a / -0.60 1.80 t total ƒ 17.73 per tonne of alloyed material Although these amounts are to be used globally, they nevertheless illustrate the significant cost advantage achieved lean. "COCLUSIONS 6. Alloying agent for aluminum, characterized in that it at least in part, it consists of a pre-alloying of ferroalloys of the desired alloying elements with aluminum. ! i * * I Aluminum alloy obtained by the method of one or more of the claims 1 to 5 · 3 | 31 * * Ï i \ ï i i A 4 i «t I i A i \ 'i \ ,: \ * 790 5 5 47