Method for purifying Al-Ti-B alloy melt

This application is 371 of PCT/CN2010/072559 filed 05/10/2010.

The present invention relates to methods for alloy materials fabrication, especially to a method for purifying Al(aluminum) -Ti(titanium) -B (boron) alloy melt.

Currently, Al—Ti—B alloy basically employ materials of K2TiF6+KBF4 as additive materials for Ti—B elements, and during a reaction processing, a reaction product of mKF·AlF3 is likely to form into macromolecular compounds and mix with Al(TiB2+TiAl3) which causes it hard to be separated out. In this case, a purify degree and a refinement ability are extensively deceased. In traditional fabrication processes, it has been a problem to find a solution for separating the macromolecular reaction product of mKF·AlF3 out of the Al(TiB2+TiAl3) alloy for long.

Huge potential safety hazards could be brought out to Al and Al alloy materials when dregs like mKF·AlF3 distributed in the Al(TiB2+TiAl3) alloy are not eliminated effectively or keep down to a certain amount, and the Al(TiB2+TiAl3) alloy with such dregs are still used as additives for refining of crystal grains of Al and Al alloy. If the Al and Al alloy with such dregs of mKF·AlF3 are used for fabrication of Al plates of plane wings, where the dregs located are likely to become inducement points of mangling due to a low temperature and a high pressure in flight.

What is needed, therefore, is a method for purifying Al—Ti—B alloy that can overcome or mitigate the above-described deficiencies.

It is an object of the present invention to provide a method for purifying Al—Ti—B alloy.

One exemplary embodiment of the present invention is a method for purifying Al-Ti-B) alloy includes putting and melting industrial aluminum ingot in an electromagnetic induction smelting furnace, the melt of Al being covered by a high-temperature covering agent, and its temperature up to at about 670˜900° C.;adding material of K 2 TiF 6 and KBF 4 into the smelting furnace and then stirring the compounds therein to react; adding compound comprising Mg, L, Na and F to the evenly stirred K 2 TiF 6 and KBF 4 , the compound having an amount about 0.01%˜1% of a sum weight of total K 2 TiF 6 and KBF 4 , and uniformly stirring for about 15˜60 minutes under a reaction temperature being constantly at about 670˜900° C., the dregs being removed, the Al alloy being casting molded.

Other novel features and advantages will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.

Step A: Industrial aluminum ingot are put into and melted in an electromagnetic induction smelting furnace. After that, the melt of Al is covered by a high-temperature covering agent, and its temperature is at about 700±10° C.

Step B : Material of K 2 TiF 6 and KBF 4 are added into the smelting furnace and then compounds therein are stirred to react in accordance with the following reaction formula:

In the reaction product of mKF·nAlF 3 , m+n≦200. In the alloy of Al (TiB 2 +TiAl 3 ), a proportion of Ti is about 1˜5%, a proportion of B is about 0.001˜0.5%, and the rest is Al. An amount of K 2 TiF 6 and KBF 4 are determined according to the formula that should ensure a fully reaction. In a normal situation, an amount of K 2 TiF 6 and KBF 4 that should be added into is about 20˜40% and 20˜60% of a total weight of the Al melt, respectively.

Step C: Mg(magnesium)F(fluorine) x ·Li(lithium)F y ·Na(sodium)F z is added. An amount of MgF x ·LiF y ·NaF z is 0.1% of a sum weight of K 2 TiF 6 and KBF 4 . Uniformly stirring for about 15˜60 minutes under a reaction temperature being constantly at about 700±10° C., the dregs including mKF˜nAlF 3 are removed thereas, and the Al alloy is casting molded. A whole reaction process has employed at least 3 layers of windings to generate magnetic vibrations. When there are 3 layers of windings, their vibration frequencies are at 50 HZ, 500˜1200 HZ, and 1500˜2500 HZ, respectively. The reaction process is guaranteed with uniform vibration waves, such that the melt can be uniformly vibrated and groups of grains of TiB 2 have an average diameter no more than 2 μm. During the above mentioned reaction process, by adding proper amount of MgF x ·LiF y ·NaF z , a polymerization of mKF·nAlF 3 is effectively prevented or at least blocked. Compounds including element K(potassium) has an amount reduced from about 5 g/kg using the traditional processes to 0.01 g/kg using the method for purifying Al—Ti—B alloy of the present invention. Therefore an impurity amount of the after products is extensively decreased.

The product of Al-TiB alloy can used for refining of other Al and Al alloy crystal grains, with an additive amount of 1˜5‰, in order to improve the refinement ability of Al and Al alloy crystal grains.

Step A: Industrial aluminum ingot are put into and melted in an electromagnetic induction smelting furnace. After that, the melt of Al is covered by a high-temperature covering agent, and its temperature is at about 750˜850° C.

Step B : Material of K 2 TiF 6 and KBF 4 are added into the smelting furnace and then compounds therein are stirred to react in accordance with the following reaction formula:

In the reaction product of mKF·nAlF 3 , m+n≦200. In the alloy of Al (TiB 2 +TiAl 3 ), a proportion of Ti is about 1˜5%, a proportion of B is about 0.001˜1%, and the rest is Al. An amount of K 2 TiF 6 and KBF 4 are determined according to the formula that should ensure a fully reaction. In a normal situation, an amount of K 2 TiF 6 and KBF 4 that should be added into is about 20˜40% and 20˜60% of a total weight of the Al melt, respectively.

Step C: MgF x ·LiF y ·NaF z is added. An amount of MgF x ·LiF y ·NaF z is 0.5% of a sum weight of K 2 TiF 6 and KBF 4 . Uniformly stirring for about 15˜60 minutes under a reaction temperature being constantly at about 750˜850° C., the dregs are removed thereas, and the Al alloy is casting molded. A whole reaction process has employed at least 3 layers of windings to generate magnetic vibrations. When there are 3 layers of windings, their vibration frequencies are at 50 HZ, 500˜1200 HZ, and 1500˜2500 HZ, respectively. The reaction process is guaranteed with uniform vibration waves, such that the melt can be uniformly vibrated and groups of grains of TiB 2 have an average diameter no more than 2 μm.

During the above mentioned reaction process, by adding proper amount of MgF x ·LiF y ·NaF z , a polymerization of mKF·nAlF 3 is effectively prevented or at least blocked. Compounds including element K(potassium) has an amount reduced from about 5 g/kg using the traditional processes to 0.01 g/kg using the method for purifying Al—Ti—B alloy of the present invention. Therefore an impurity amount of the after products is extensively decreased.

The product of Al-TiB alloy can used for refining of other Al and Al alloy crystal grains, with an additive amount of 1˜5‰ in order to improve the refinement ability of Al and Al alloy crystal grains.

It is to be understood, however, that even though numerous characteristics and advantages of exemplary and preferred embodiments have been set out in the foregoing description, together with details of the structures and functions of the embodiments, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.