JPS61106731A - Production of ingot of high melting active metallic alloy - Google Patents

Abstract

PURPOSE:To produce an ingot of a titled alloy having uniform and small crystal grains at a low cost by mixing and molding plural kinds of powder metals consisting essentially of a high melting active metal and melting the same in a plasma electron beam using a hollow hot-cathode thereby producing the alloy. CONSTITUTION:The hollow hot-cathode 2 made of tantalum is suspended in a melting chamber 1 and a water cooled copper crucible 3 is disposed in the position where said crucible faces the cathode. A focusing coil 4 is provided to enclose a plasma electron beam passage extending to the cathode 2. A raw material supply mechanism 6 is provided on the outside between the cathode 2 and the crucible 3 and the molding 5 mixed with plural kinds of powder and sponge-like metals consisting essentially of the high melting metal (Ti, Zr, Nb, Ta, etc.) is supplied from a horizontal direction to the mechanism. The molding 5 is melted in this state by the plasma electron beam under 1X10<-2>-1X10<-4>Torr working pressure and an ingot 7 is produced while the crucible 3 is pulled down by a pulling down mechanism 8.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is applicable to titanium, zirconium, niobium, tantalum,
It is a method for melting an alloy consisting of two or more kinds of active metals with a high melting point such as molybdenum and tungsten as a base.

Conventional Techniques Conventionally, the arc melting method and the electron beam method are generally known as methods for producing alloys consisting of two or more metals belonging to the groups ■b, yh, and ν1 of the periodic table of the elements. There is. The arc melting method uses a consumable electrode made by bundling rod-shaped or plate-shaped materials made of multiple alloy components into a desired composition ratio and forming them into a rod or plate shape in a pure atmosphere or an inert gas atmosphere. There is a method of forming an agglomerate by arc melting in a medium, or a method of mixing powders or sponges of multiple types of alloy components to a desired composition ratio, compression molding, and forming a consumable electrode in the same manner as the above method. As known examples of such consumable electrodes, reference may be made to Utility Model Publication No. 33-3!04 and Japanese Patent Publication Akihiro A-/74LIJ.

In addition, the electron beam melting method can produce molten metal, which is made by bundling rod-shaped materials or plate-shaped materials made of multiple types of alloy components to a desired composition ratio and forming them into a rod or plate shape, or powder made of multiple types of alloy components. In this method, a molding raw material or a fluid raw material mixed with sponge in a desired composition ratio is irradiated and melted with an electron beam in a vacuum atmosphere to form an agglomerate.

Problems to be Solved by the Invention By the way, in the conventional consumable electrode type arc melting method as described above, metal is melted in a water-cooled copper furnace, and the molten metal rapidly and sequentially moves upward in layers. and coagulation is performed. Therefore, the alloy ingotted in this way has a non-uniform composition and is likely to cause segregation, and in some cases, alloy components with extremely high melting points may remain in an unmolten state.

When used as a superconducting material to make agglomerates using the consumable electrode type arc melting method using Nb-Ti alloy rod-shaped or plate-shaped raw material bundles, it is necessary to uniformize the composition once. It is necessary to form the melted agglomerated agglomerate into a consumable electrode by forging again, and repeat arc melting. This not only complicates the process, but also reduces the yield of Vc EX ingots due to repeated arc melting and cutting when remolding consumable electrodes. It is below 0. In addition, the raw material must always be an electrode shaped into a rod. Therefore, a consumable electrode made of rod-shaped or plate-shaped raw materials of multiple types of ingredients is used)
This method has the disadvantage that it takes time and effort to uniformly combine these rod-shaped or plate-shaped raw materials into a molded body. On the other hand, when powders or sponge materials of multiple alloy components are mixed in a desired composition ratio and molded and a friend electrode is used, it is easy to mold the electrode. is also uniform. However, powdered raw materials contain oxygen, nitrogen, or moisture due to their nature.9. Further, in the arc melting method, the pressure inside the melter is generally 7 to 100 Torr, so no degassing occurs. A large amount of the above-mentioned gas components remains in the ingot produced by Shichi no Tomome, which impairs subsequent workability. For example, the superconducting material of Nb-Ti alloy is 0.0
It is usually used as an ultra-fine wire of approximately Jtxxφ, and the final superconducting property is determined by the large cross-sectional area reduction rate (i.e. cold working rate) of the final wire processed from the raw material ingot without any intermediate annealing. It is known that it is very arrogant. However, the ingot formed by the above method is prone to cracking during rolling and wire breakage during wire drawing.

In this way, in the consumable electrode type arc bath welding method, it is necessary to use a rod-shaped raw material as a consumable electrode, the dissolution rate is constant and cannot be adjusted arbitrarily, and the component elements are consumed in advance. It is necessary to mix the ingredients uniformly throughout the substrate, and to obtain uniformity, it is necessary to perform double melting or three-way melting, which results in poor yields, and it is difficult to mix sponge or powdered raw materials. When a molded product is used as a consumable electrode, residual gas components in the IC in the agglomerate also pose a problem.

Further, in the electron beam f& solution, the molten metal is overheated because it is melted by irradiating an electron beam with a high power Vj in a vacuum of /X 10-'Torr or less. Therefore, the evaporation of components with high vapor pressure is significantly reduced, and the alloy composition of the agglomerate tends to be non-uniform. For example, even in the case of Nb-Ti, since the vapor pressure of Ti is significantly higher than that of NMC, it is extremely difficult to produce an agglomerate with uniform alloy composition in which the evaporation reduction of Ti is extremely uniform. Furthermore, in the electron beam scanning method, since the voltage is small and the current is small, no electromagnetic stirring effect occurs, and it is difficult to obtain a uniform composition even though the alloy solidifies.

Therefore, in the electron beam bath method, when the vapor pressures of the component elements are low, it is difficult to distort the component image, and there is no electromagnetic stirring effect, so the agglomeration tends to be non-uniform. &M There is a problem with adjusting the speed.

Therefore, in consideration of the problems of the conventional methods described above, the present invention uses a mixture of powdered or sponge raw materials that can easily obtain a macroscopically uniform composition, and can be sufficiently degassed to form agglomerates. Does gas remain in things? In addition, the operating pressure can be set over a wide range, the melting rate and melting rate can be adjusted to any desired value, and the electromagnetic stirring effect of the molten metal can be obtained in the same way as the arc age method. The purpose of this invention is to provide a method for producing small, uniform composition, high melting point active metal alloys.

Means for Solving the Problems In order to achieve the above objects, according to the present invention, a hollow hot cathode is used as a plasma electron beam total heating means, and a plurality of types of powders having high melting point active metals as a base are used. A method for producing a melting point active metal alloy is provided, which is characterized by melting a molded or fluid raw material mixed with a spongy metal to produce a desired alloy 1.

Function As described above, in the method according to the present invention, since a plasma electron beam using a hollow hot cathode is used as a heating source,
Working pressure 'ii-/X 104~/XIO'' TOrr
It can be applied over a wide range of 7 tl [more stable primary heat action, and at a lower pressure of 7 tl (E+), the evaporation of metal vapor is suppressed, but the degree of vacuum is low enough to release gas components. can be,
Therefore, even powdered raw materials can be sufficiently degassed and will not remain in the gas during agglomeration.

Furthermore, since it is a low voltage, high current (electron beam), the dissolution rate can be adjusted as desired, and an electromagnetic stirring action for hot water supply based on the self-current can be obtained. Furthermore, the depth of the bath can be reduced, and a uniform composition of the corpse can be obtained when the slag solidifies.

The raw material used in the present invention is in the form of a mixture of multiple types of powdered or cylindrical metals (including a high melting point active metal as a base) (it may be a molded material or an unformed fluid material). ), and the supply of step 7 can be carried out in the same manner as in the conventional electron beam melting method, i.e., for example, raw material 1.1 is laterally fed into a water-cooled copper lubrication tube and plasma is applied from above. If the raw material is a molded material, it may be suspended from above the crucible and the plasma electron beam may be irradiated from the side.Furthermore, if the raw material is a molded material, it may be irradiated from the top of the crucible with the plasma electron beam. Ruh? It may also be made to fall inside. Note that in either method, a plurality of hollow cathode plasma electron guns may be used.

The alloy melted in this manner is sequentially lowered from the crucible, and by rotating the alloy at this time, the outer circumferential surface of the PjJJ ingot can be finished smoothly.

The following describes the method of the present invention with reference to the accompanying drawings. An example of the TA-made i&so currently in use will be explained.

The illustrated device uses powder forming raw materials,
/ is 8 pages extending vertically! A hollow hot cathode made of Tammel is suspended from above inside the soaking chamber in one chamber, and a water-cooled copper crucible 3 is placed opposite to this hollow hot cathode. A yarn bundle coil is arranged surrounding the path of the plasma electron beam extending from the water-cooled copper nut de3 to the hollow lA cathode λ. Between the hollow hot cathode and the water-cooled copper crucible 3, a raw material feeder r47 for feeding powder forming raw material j'fr from the lateral direction is provided outside the melting chamber l. Further, on the lower side of the melting chamber 1, there is provided a pull-down mechanism t for pulling down from the water-cooled copper crucible 3 to the ingot ingot 7.

As explained above, the present invention uses a plasma electron beam using a hollow cathode as the heating means, so the working pressure is f/X10-"~lx10"-'To
It is possible to obtain a wide range of rr, to achieve a sufficiently low degree of vacuum for gas release, and to use powdered or spongy raw materials tf, which are easy to assemble uniformly from a macroscopic point of view, without leaving any gas in the agglomerated ingot. It is possible to form an ingot with a uniform alloy composition, a small crystal grain size, and few impurities by melting twice.

In addition, since there is no need to carry out two-wheel melting or triple melting in the consumable storm arc melting method, not only can the ingot-forming cost be reduced, but the yield can also be greatly improved. Furthermore, the metal structure of the ingot made by the method according to the present invention shows that the crystal grains are about A8TM-No, M-1, and have slight a'c a'c grains. Therefore, according to the method of the present invention, an alloy with extremely good plastic workability can be obtained.

[Brief explanation of the drawing]

The drawing is a schematic illustration of an example of an apparatus implementing the method of the invention.

Claims (1)

[Claims] Forming a mixture of multiple types of powder or sponge metals based on a high melting point active metal using a plasma electron beam using a hollow hot cathode as a heating means, or melting fluid raw materials to produce a desired alloy. A method for producing high melting point active metal alloys.