JPH0372136B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical field to which the invention pertains] The present invention relates to a consumable electrode for alloy melting consisting of two or more types of high melting point active metals, and in particular to a Nb-Ti alloy,
This invention relates to a consumable electrode used in melting by a consumable electrode type vacuum arc melting method. [Prior art] Titanium alloys containing high-melting point metals such as Nb-Ti alloys cannot be homogeneously melted using the ordinary consumable electrode vacuum arc melting method due to the significant difference in melting point and specific gravity between them and the alloy component metals. However, it is difficult to obtain an ingot without segregation. Conventionally, as a method to solve the above-mentioned problems, various methods regarding consumable electrodes have been applied to titanium alloys containing several percent of high-melting point metals, such as Ti-5wt%Ta (hereinafter wt% is simply abbreviated as %). Although improved methods have been made, there have been few reports on alloys containing about half of high melting point metals.Consumable electrodes reported on Ti-5% Ta alloys and the like are as follows. A consumable electrode made by thoroughly mixing the base metal and alloy component metal and molding it into a compact shape (Special Publication Publication No. 49-8607
issue). A consumable electrode made of a large number of thin plates of base metal and alloy component metal stacked in parallel in the longitudinal direction
No. 120811). Mix the base metal and alloy component metal powder well,
A consumable electrode (Japanese Patent Publication No. 17413/1983) is made by compression molding this mixture, inserting it into the center of a base metal, and molding it into a compact shape. However, when these consumable electrodes are applied to Nb-Ti alloys, they have the following drawbacks. In order to manufacture the first electrode, the average particle size of the titanium sponge is 0.8 mm to 13 mm and the bulk specific gravity is about 1.3, and the average particle size of the niobium powder is 0.07 mm to 1.0 mm and the bulk specific gravity is about 4.5. There is a large difference in particle size and bulk specific gravity,
It is extremely difficult to mix uniformly. In the electrode formed by the method of stacking a large number of second thin plates, it is expensive to obtain the thin plates themselves, and inert gas welding within the chamber is difficult. In the production of the third electrode, titanium powder has a high oxygen content and is expensive, and since niobium and titanium are used in approximately half each, a compression-molded compact after mixing is mounted on the base metal. I cannot do the operation of entering it. The object of the present invention is to overcome these drawbacks and provide a consumable electrode that has a uniform composition, is free from segregation, and is capable of melting titanium alloys containing about half of niobium. [Structure of the Invention] That is, the present invention is a Nb- The present invention provides a consumable electrode for melting Ti alloy. In the compact according to the present invention, the average particle size of the outer titanium sponge is usually 10 mm or less, preferably 5 mm.
mm or less, and the average particle size of the inner niobium grains or powder is usually 50 mm or less, preferably 5 mm or less. The reason why the niobium particles or powder are wrapped in this titanium sponge is that compression molding of only the niobium particles or powder would cause seizure on the mold wall, so by using fine titanium sponge, the niobium particles Alternatively, reduce the area where the powder comes into contact with the mold wall to prevent seizure of the mold wall. Several of the compacts compressed in this manner are placed in a titanium sponge with an average grain size of 50 mm or less, compression molded, and then welded to form a consumable electrode. [Embodiments of the Invention] Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal cross-sectional view of a press mold for compact production. First, a core 2 is placed in a press mold 1, a niobium powder 3 is placed inside the core 2, and a titanium sponge 4 is charged to the outside so as to cover the niobium powder 3.After pulling out the core 2, the core 2 is properly smoothed and compression molded. do. The shape of the compact 5 obtained by this is shown in the second perspective view.
As shown in the figure. Next, as shown in FIG. 3, six compacts 5 are placed in a titanium sponge 6, compression molded to obtain briquettes 7, and a plurality of these briquettes 7 are welded to form a consumable electrode. FIG. 4 is a longitudinal sectional view of the consumable electrode 8 manufactured in this manner. 9 is a joint with a power source. Table 1 shows the results of producing a Nb-50% Ti alloy by triple melting the consumable electrode 8 in a vacuum arc. Table 1 shows the results of producing a 1500Kg ingot.

[Table] [Effects of the Invention] As is clear from the results of the above examples, the consumable electrode of the present invention is suitable for melting a Nb-Ti alloy with a uniform composition and no segregation. In particular, the electrode of the present invention is excellent for melting Nb-Ti alloys, which are commonly used as superconducting materials and aircraft fastener materials. It has the excellent effect of being able to produce an alloy with a uniform composition even when it contains about 40 to 60%).

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, and FIG. 1 is a longitudinal cross-sectional view of a press mold for producing a compact, FIG. 2 is a perspective view of the compact, FIG. 3 is a perspective view of a briquette for a consumable electrode, and FIG. FIG. 3 is a longitudinal cross-sectional view of a consumable electrode. 1... Press mold for compact manufacturing, 2... Core, 3
... Niobium grains or powder, 4... Sponge titanium,
5... Compact, 6... Titanium sponge, 7... Briquette, 8... Consumable electrode, 9... Joint.

Claims (1)

[Claims] 1. In a consumable electrode for Nb-Ti alloy melting, a compact made by wrapping niobium grains or powder in titanium sponge and compression molding is inserted into titanium sponge and compression molded, and from this molded body. An electrode characterized by comprising: 2. The electrode according to claim 1, wherein the average particle size of the niobium particles or powder is 50 mm or less. 3. Claim 1, wherein the average particle size of the titanium sponge containing niobium grains or powder is 10 mm or less
Electrode as described in Section. 4. The electrode according to claim 1, comprising a compact inserted into titanium sponge having an average particle size of 50 mm or less.