JPH04333542A - Al-b alloy and its manufacture - Google Patents

Abstract

PURPOSE:To manufacture an Al-B alloy having low viscosity, good in the separability of flux and capable of easily casting by adding KBF4 to the molten metal of Al with a specified temp. to form the total B into AlB2 crystals and thereafter adding K2TiF6 thereto to regulate its comps. into a specified one. CONSTITUTION:A prescribed amt. of KBF4 is added to the molten metal of Al in the temp. range of 680 to 850 deg.C, and they are brought into reaction with to form the whole B into AlB2 crystals. The molten metal of the Al-B alloy provided with high viscosity by the above method is mixed with a small amt. of K2TiF6 to regulate its viscosity. At this time, the amounts of B and Ti to be added are regulated into an Al-B alloy contg., by weight, 0.001 to 0.05% Ti and 2 to 7% B and in which the whole B is constituted of AlB2 crystals. In this way, the high viscosity of the above molten metal is dissolved to enable easy molding.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to Al-B used as a conductivity improver and neutron absorber for aluminum electric wires.
Related to alloys and their manufacturing methods.

0002

[Prior Art] U. S. P. 3503738, Al metal is briquetteted with KBF4, added to molten aluminum, reacted at 900°C,
The Al-B alloy is manufactured at a reaction temperature of 1000°C or higher. Also, in JP-A-62-1834, 660-80
When adding borofluoride to 0°C Al molten metal to produce an Al-B2 intermetallic compound, alkali fluoride is added,
A method of controlling reaction temperature is disclosed. In the Al-B manufacturing method, when the reaction temperature is raised to 900°C or higher, A
All lB2 changes to AlB12 crystals, and AlB
No. 12 has the disadvantage that the effect of improving the conductivity of aluminum is reduced. In addition, in the method in which the molten metal temperature is 660 to 800°C, AlB2 is generated, but the viscosity of the Al-B molten metal increases, and it is difficult to separate the flux just by adding alkali fluoride, resulting in a large amount of flux mixed into the product. In addition, the molten metal had poor viscosity and could not be cast into a mold.

0003

OBJECTS OF THE INVENTION The problem to be solved by the present invention is to solve the above-mentioned disadvantages of conventional Al-B alloys, especially Al-B alloys which are raw materials for producing aluminum electric wires.

0004

[Means for Solving the Problems] The inventors investigated various methods for producing an Al-B alloy consisting only of AlB2 crystals with few clusters, and found that KBF4 is reacted with aluminum at a reaction temperature in the range of 680 to 850°C. Generated AlB
It has been found that by adding a small amount of K2TiF6 to a molten Al-B alloy containing two crystals, an Al-B alloy with low viscosity and easy to cast can be obtained.

[0005]

Structure of the invention and its operation: AlB2 has A at 920°C.
metastasizes to lB12 [Atoda, Higashi, Kobayashi, Sci. Pa
t. Inst. Phys. Chem. Rev. 61(3
), 92 (1967)], it is important to control the heat generation of the reaction between Al and KBF4 and suppress the temperature rise during the reaction. The transition to AlB12 is at 920°C, but A
In order to maintain the crystalline form of the l-B interphase compound in AlB2 and to maintain the viscosity of the molten metal in a good state, the temperature must not exceed 850°C.

When KBF4 is added while keeping the Al molten metal at 730°C, the temperature reaches about 800°C due to an exothermic reaction, so the addition is stopped, the temperature is lowered to 730°C again, and KBF4 is added again.
Add 4. In this way, KBF4 is reacted with Al while controlling the temperature to 850°C or lower, preferably 780°C or lower. The Al-B molten metal produced at this time has a very high viscosity. In particular, if the B content is 5% by weight or more, it becomes difficult to stir the molten metal. When this molten metal was sampled, cooled and solidified, and the structure of the alloy was examined, it was revealed that AlB2 crystals were bonded in a network pattern. This network structure was found to be the cause of the increase in viscosity. As a result of examining various methods for destroying this network, it was found that K2TiF6 treatment destroys this network structure and lowers the viscosity of the Al-B molten metal. Originally, Ti was 0.01 in aluminum metal.
% or less, but when KBF4 is added, this Ti
It changes to iB2 and has no effect on cutting the network structure during Al-B alloy formation. Ti in K2TiF6 added after the network structure is formed is reduced and dissolved into the molten metal, cutting the AlB network. When an optimal amount of K2TiF6 was added to this Al-B molten metal, which had poor viscosity and was difficult to stir, the viscosity of the molten metal immediately improved (reduced) and it became possible to stir it easily. It was also easy to drain from the crucible and could be poured into any mold. When the K2TiF6-treated Al-B molten metal was collected, cooled and solidified, and the structure of the alloy was examined, it was found that AlB2 crystals existed independently and the network pattern had completely disappeared. A treated with K2TiF6 in this way
The 1-B alloy contained 0.001 to 0.05% Ti, and all boron was formed into AlB2 crystals and existed independently in Al. It is said that Ti in Al alloys deteriorates conductivity, but the Ti contained here is
2, and it was recognized that the conductivity of aluminum was not reduced. In the present invention, it is possible to produce a material with a boron content of up to 7%.

[0007] The molten Al-B alloy with poor viscosity produced by the reaction between KBF4 and Al is treated with Al-B by K2TiF6 treatment.
By improving the viscosity of the molten B alloy, it has become possible to easily produce an Al-B alloy with a high boron concentration that contains only AlB2 crystals with few clusters even when the boron content is increased. As a result, the efficiency of improving the conductivity of aluminum increases,
Also, it has become easier to manufacture aluminum materials for neutron absorption.

[0008]

EXAMPLES In order to clarify the technical content of the present invention, representative examples will be extracted and illustrated as examples. Example 1. 360 kg of aluminum is placed in a graphite crucible, melted, and kept at 740°C. First of all, KBF485kg
Inject and react. The reaction temperature rose to 820°C. After removing the upper layer generated flux, KBF488
Add kg. The reaction temperature after this step is up to 780℃.
It was carried out at temperatures up to ℃. Then add a small amount of K2TiF6,
Adjust the viscosity of Al-B molten metal. remaining KBF415k
After adding and reacting, K2TiF6 was added,
Adjust the viscosity of molten metal. After the adjustment is completed, the flux is removed and the molten Al-B alloy is poured into a mold. 340 kg of Al-4%B alloy was obtained. The Ti content of this is 0.0
1% and the boron content was 4.2%. As a result of microstructural examination of the alloy, all boron crystals were AlB2 and independently present in Al. In addition, almost no clusters were observed. Example 2. 360 kg of molten aluminum is placed in a graphite crucible and the temperature is brought to 720°C. KBF4100K for this
Add g. Although the reaction temperature increases, it is controlled at a maximum of 820°C. After removing the generated flux, KBF4100
kg was reacted. At this point, the viscosity of the molten metal increased considerably, and the separation of the flux and metal deteriorated. After adding a small amount of K2TiF6 and again removing the generated flux that improves the viscosity of the Al-B melt and increases the stirring efficiency, 488 kg of KBF was added. K2TiF6 is added again to reduce the viscosity of the Al-B molten metal and improve its fluidity. After removing the generated flux, it is poured into a mold and Al-
305 kg of 5% B alloy was obtained. As a result of microstructural examination of this alloy, it was found that the crystals were AlB2 and no network structure was observed. Furthermore, the presence of clusters was hardly recognized. The Ti content of this material was 0.02%, and the boron content was 5.3%. Example 3. The same operation as in Example 2 was carried out by keeping 304 kg of molten Al at 720° C. and dividing 4250 kg of KBF into this into three portions. As a result, 250 kg of Al-6% B alloy containing 6.3% boron and having good viscosity was obtained. The Ti content of this material was 0.04%, and all boron intermetallic compounds were AlB2 crystals. Example 4. 365Kg KBF of Al molten metal kept at 720℃
4,150 kg was divided into two doses. After the input is complete,
K2TiF6 was added to improve the viscosity of the Al-B molten metal. After removing the generated flux, pour it into a mold and add boron 3.
340 kg of Al-3% B alloy containing 10% was obtained. The Ti content of this material is 0.01%, and all boron is Al.
It consisted of B2 crystals.

Claims (2)

[Claims] 1. An Al-B alloy containing 0.001 to 0.05% by weight of Ti and 2 to 7% by weight of boron, and characterized in that all of the boron consists of AlB2 crystals. Claim 2: Add KBF4 to molten Al to convert all boron into AlB2 crystals, and then add K2TiF6 to form Al-
Adjusting the viscosity of the B molten metal, improving flux separation, and producing an easy-to-cast Al-B alloy at 680-850℃
A method for producing an Al-B alloy containing 2 to 7% boron, characterized in that the process is carried out in a temperature range of 2 to 7%.