JP2535678B2 - Method for producing Al-B alloy - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to Al-B used as a conductivity improving material and a neutron absorbing material for aluminum electric wires.
The present invention relates to a method for manufacturing an alloy .

[0002]

2. Description of the Related Art U.S.P. S. P. As disclosed in 3503738, Al metal is briquetted with KBF ₄ , added to molten aluminum and reacted at 900 ° C.
An Al-B alloy is manufactured at a reaction temperature of 1000 ° C or higher. Further, in JP-A-62-1834, 660-80
When a borofluoride is added to an Al melt at 0 ° C. to produce an Al-B ₂ intermetallic compound, an alkali fluoride is added,
A method of controlling the reaction temperature is disclosed. In the Al-B manufacturing method, if the reaction temperature is raised to 900 ° C or higher, A
lB ₂ ends up changing in all AlB ₁₂ crystal, AlB ₁₂
Then, there arises a drawback that the effect of improving the conductivity of aluminum is lowered. In addition, although AlB ₂ is produced by the method in which the molten metal temperature is 660 to 800 ° C., the viscosity of the Al-B molten metal becomes large, and it is difficult to separate the flux only by adding alkali fluoride, and a large amount of flux is present in the product. In addition to having the drawback of being mixed, the melt had a poor viscosity and could not be cast into a mold.

[0003]

The problem to be solved by the present invention is to eliminate the above-mentioned drawbacks of the conventional Al-B alloy, which is a raw material for producing aluminum electric wires, in particular.

[0004]

As a result of various studies on the production method of an Al-B alloy consisting only of AlB ₂ crystals with few clusters, the inventors have reacted KBF ₄ with aluminum within a reaction temperature range of 680 to 850 ° C. Generated AlB ₂
It was found that by adding a small amount of K ₂ TiF ₆ to the molten Al-B alloy containing crystals, an Al-B alloy having low viscosity and easy to cast can be obtained.

[0005]

Structure of the Invention and Its Function AlB ₂ is A at 920 ° C.
Transferred to LB ₁₂ [Atoda, Higashi, Kobayashi, Sci.Pat.Inst.P
hys.Chem.Rev.61 (3), 92 (1967)], it is important to control the heat generation of the reaction between Al and KBF ₄ and suppress the temperature rise during the reaction. Although the transition to AlB ₁₂ is 920 ° C., the crystal form of the Al-B interphase compound is retained in AlB ₂ ,
Moreover, the temperature is 850 ° C to keep the viscosity of the molten metal in good condition.
Must not exceed.

When KBF ₄ is added while keeping the molten aluminum at 730 ° C., an exothermic reaction reaches 800 ° C., so the addition is stopped, the temperature is lowered to 730 ° C. again, and KBF ₄ is again added.
Add ₄ . Thus, KBF ₄ is reacted with Al while controlling the temperature at 850 ° C. or lower, preferably 780 ° C. or lower. The Al-B melt generated at this time has a very high viscosity. Especially when the B content is 5% by weight or more, it becomes difficult to stir the molten metal. When this molten metal was sampled, solidified by cooling, and the structure of the alloy was examined, it was revealed that the AlB ₂ crystals were bonded in a mesh pattern. It was found that this network structure is the cause of the increase in viscosity. As a result of various studies on the method of destroying the network, it was found that the treatment with K ₂ TiF ₆ destroys the network structure and reduces the viscosity of the Al-B melt. Originally aluminum metal has 0.01% Ti
Although it is included below, this Ti is Ti when KBF _{4 is} added.
It changes to B ₂ and has no effect on the cutting of the network structure at the time of forming the Al—B alloy. K added after forming the network structure
₂ Ti in TiF ₆ is reduced and melts into the molten metal
It cuts IB. This viscous and difficult to stir A
When the optimum amount of K ₂ TiF ₆ was added to the LB melt, the viscosity of the melt immediately improved (decreased) and the stirring became easy. Moreover, it was easy to flow out from the crucible and could be poured into any mold. Al-B treated with K ₂ TiF ₆
When the molten metal was sampled, cooled and solidified, and the structure of the alloy was inspected, AlB ₂ crystals were independently present and the mesh pattern was completely disappeared. Thus, the K ₂ TiF ₆ treated Al-B alloy contained 0.001 to 0.05% of Ti, and all the boron became AlB ₂ crystals, which were independently present in Al. It is said that Ti in the Al alloy deteriorates the conductivity, but the Ti contained therein is TiB ₂ and it was confirmed that the conductivity of aluminum is not deteriorated. In the present invention, it is possible to manufacture up to a boron content of 7%.

A molten Al-B alloy having a low viscosity produced by the reaction between KBF ₄ and Al is treated with K ₂ TiF ₆ to form Al-B.
By improving the viscosity of the molten alloy, it becomes possible to easily manufacture an Al-B alloy having a high boron concentration and containing only AlB ₂ crystals having few clusters even if the boron content increases. As a result, the efficiency of improving the conductivity of aluminum was improved, and the production of an aluminum material for neutron absorption was facilitated.

[0008]

EXAMPLES In order to clarify the technical contents of the present invention, representative examples will be extracted and illustrated as examples. Example 1. 360 kg of aluminum is put into a graphite crucible and melted and kept at 740 ° C. First, 85 kg of KBF ₄ is added to this and reacted. The reaction temperature rose to 820 ° C. After removing the generated flux of the upper layer, KBF ₄ 88
KG is added. The maximum reaction temperature after this step is 780
Performed up to ℃. Then add a small amount of K ₂ TiF ₆
Adjust the viscosity of the LB melt. After the remaining 15 kg of KBF ₄ was added and reacted, K ₂ TiF _{6 was} further added to adjust the viscosity of the molten metal. After the adjustment is completed, the flux is removed and Al
Cast the B alloy melt into the mold. Al-4% B alloy 340
kg was obtained. This had a Ti content of 0.01% and a boron content of 4.2%. As a result of the structure inspection of the alloy, all the boron crystals were AlB ₂ and independently existed in Al. Almost no clusters were observed. Embodiment 2. FIG. 360 kg of molten aluminum is put into a graphite crucible and the temperature is brought to 720 ° C. To this is added 100 kg of KBF ₄ . The reaction temperature rises but is controlled up to 820 ° C. After removing the produced flux, 100 kg of KBF ₄ was added by reaction. At this point, the viscosity of the molten metal increased considerably and the separation of flux and metal deteriorated. K
₂ Add a small amount of TiF ₆ to improve the viscosity of Al-B melt and improve the stirring efficiency.
88 kg of F ₄ was added. K ₂ TiF ₆ was added again, and Al was added.
-Lower the viscosity of the B melt and improve the fluidity. After removing the generated flux, it is cast into a mold and Al-5% B alloy 3
05 kg was obtained. As a result of inspecting the structure of this alloy, the crystal was AlB ₂ and no network structure was observed. Moreover, the existence of clusters was hardly recognized. The Ti content of this material is 0.02%, and the boron content is 5.3.
%Met. Example 3. 304 kg of Al melt was kept at 720 ° C., 250 kg of KBF ₄ was divided into 3 times, and the same operation as in Example 2 was performed. As a result, a viscous boron-containing 6.3% Al
250 kg of -6% B alloy was obtained. The Ti content of this material is 0.04%, and all the intermetallic compounds of boron are AlB ₂
It was a crystal. Example 4.7 Molten Al kept at 720 ° C. 365 kg KBF ₄
150 Kg was added in two batches. After the end of feeding, K ₂
TiF ₆ was added to improve the viscosity of the Al-B melt. After removing the generated flux, it is poured into a mold and boron 3.10
% Al-3% B alloy 340 kg was obtained. This thing T
The i content was 0.01% and the boron consisted entirely of AlB ₂ crystals.

Claims (1)

(57) [Claims] 1. A molten aluminum is K in a temperature range of 680-850 ° C.
After adding BF ₄ and converting all the boron into AlB ₂ crystals,
Adjusting the viscosity of Al-B melt by adding K ₂ TiF ₆
Al improves the separation of flux and makes it easy to cast.
-B alloy is produced, which contains 2 to 7% of boron.
A method for manufacturing an Al-B alloy .