SU1196405A1 - Method of producing aluminium-silicon alloys - Google Patents

Abstract

METHOD OF BLOODING ALSHINE-SILICON ALLOYS, including loading a solid charge into the metal melt, melting it, entering the alloyed elements, loading the solid charge after the entry of the leiruki elements before recharging the solid charge.

Description

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The invention deviates to the metal industry of non-ferrous alloys, in particular to the production of aluminum-silicon alloys for the production of engineering castings.

The aim of the invention is to improve the quality of the alloy by changing the sequence of melting operations, namely the modification operation,

The method is carried out as follows.

In an IAT type melting furnace, a liquid metal of approximately 20-25% of the volume of the crucible is loaded into a solid charge in accordance with the metal dumping calculation to obtain a given amount of alloy of a given chemical composition (for example, for alloy AL4: Si 9iO, Mg 0.29, Mn $ 0.38, Al - the rest),

Download lead in the following sequence; First, a return of own production is loaded (spruce profit; rejected casting. After melting the return at 750780 ° C, primary raw materials are introduced (primary aluminum of grades A6 - A8, silumin SILO, CHO, alloying elements, for example, manganese Mnl, then add 20-100% in the amount of 0.01-0j2% by weight of the total metal sludge. Gradually, t-sepe settling into the crucible, a solid mixture is added and melted at 750-770 ° C.

At 720-730 ° C, the calculated amount of magnesium is introduced into the melt with a bell and then degassed with the Degasor in an amount of 0506-0.1% by weight of the metal. After 10-13 minutes, the furnace is shut off, the slag is removed from the surface of the melt, and then reheated again to 750–780 ° C. The finished metal is poured into the casting buckets when a positive rapid analysis of chemical composition is obtained, is poured into the workshop and poured into transfer furnaces and filling and dispensing devices.

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of which the modified and refined metal is poured into casting molds.

When contained in a modifier

Strontium less than 0%, it has a low melting point, dissolves easily and practically does not interact with the chlorine-containing refining agents used.

The introduction of a modifier with a strontium content of 20-100% requires additional time for its absorption by melting and dissolution, after which subsequent degassing is possible. This is ensured by a break in carrying out the modifying treatment and degassing, which should be at least 0.5 hours between these operations. With less time

strontium does not have time to assimilate with molten aluminum. With a large time interval (more than 155-2 hours), the whole effect of the preservation of the modified state may fall on the melting itself, which is undesirable because of the reduction in the period of release from the melting furnace of the juded-fusion alloy, DHEA reduction of the possibility of intense oxidation and strontium ignition; modifier is selected in the range of 600-720 C.

With an increased content of more than 70% in strontium modifier, especially when using metallic strontium, which is susceptible to rapid oxidation, the modifier is placed in a sealed container made of aluminum-silicon alloy of the same composition as the alloy to be processed. For this purpose, cavity casting of the necessary container with a tight-fitting lid is used. Further filling the pig charge on the modifier also reduces its oxidation intensity,

Comparative data on the application of the known and proposed methods for the production of aluminum-silicon alloy AL4 are given in the table.

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Tests of the proposed method for obtaining aluminum-silicon alloys have shown that the quality of the alloy AP4 prepared in IAT-2.5 induction crucible furnaces is higher than that obtained by traditional methods. Comparison of alloy properties, mastering the master alloy, the quality of the modification shows that the application of the proposed method (Example 4-b) permits significantly. improve the mechanical properties of the metal, especially the relative elongation 1.4-2.0 times, providing a stable modified state up to 5-6 hours with low gas saturation

and also to reduce the consumption of consumed ligature by 2-2.5 times due to better absorption.

In the known method, when the modification is carried out after refining, the effect of modification does not exceed 2-2.5 hours, the alloy has an increased gas emission rate of up to 3 on the scale (VIAM) (Example 1-h)

The introduction of a ligature together with a solid mixture does not provide a qualitative modification of the alloy; it is characterized by an increased modifier deprivation and a small effect of modification.

Claims (1)

METHOD FOR PRODUCING ALUMINUM-SILICON ALLOYS, including loading a solid charge into a metal melt, melting it, introducing alloying elements, reloading a solid charge, refining and modifying treatment during the melting process, characterized in that, in order to improve the quality of the alloy, modifying processing is carried out after input alloying elements before reloading the solid charge.