JPH0154418B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention uses an electrode made from metal scrap, particularly scrap of a refractory metal such as titanium, zirconium, or an alloy thereof, as a consumable electrode in a consumable electrode type arc melting furnace. This invention relates to a method for manufacturing ingots by melting scrap. [Prior Art] Conventionally, metal scraps, particularly scraps of refractory metals such as titanium, zirconium, or alloys thereof, are melted to produce ingots.
A consumable electrode arc melting method is used. For example, to produce a titanium ingot from titanium scrap, a consumable electrode made from the molten raw material, i.e., scrap, is suspended in a water-cooled copper crucible, and a direct current is applied between its tip and the molten metal in the copper crucible. An arc is generated, which gradually melts the electrode itself from its tip, causing it to fall into a copper crucible to form a molten metal pool, and the molten metal pool is solidified from below to produce an ingot. In order to make the above-mentioned consumable electrodes from scrap using the method, the scraps are first sorted according to their size, and then larger items are welded together in the atmosphere using an argon seal to make electrodes, removing chips and granules. Or small lumps are optionally pressed together with titanium sponge to make briquettes, which are then welded together to make electrodes.
For medium-sized lumps between the above two, fine particles are crushed and optionally pressed with titanium sponge to make briquettes, which are then welded together to make electrodes. There is. [Problems to be Solved by the Invention] However, in this melting method, the method for manufacturing the consumable electrode must be changed depending on the size of the scrap, so it is necessary to sort the scraps in advance according to their size. Not only is there
Scraps in the form of chips or small lumps require additional pressing, and scraps in medium-sized lumps require even further grinding before pressing, requiring more time to make the consumable electrode. There was a problem that it took a lot of effort and time. [Means for Solving the Problem] This invention was invented in view of the above-mentioned situation, and is a method for melting metal scrap using an electrode made from metal scrap as a consumable electrode in a consumable electrode type arc melting furnace. In the method for manufacturing an ingot from the metal scrap by solidifying the molten metal thereby produced into an ingot in a water-cooled mold, the metal scrap is packed without being pressurized. A bottomed pipe made of the same material as scrap,
While the metal scrap tubes are held horizontally on a water-cooled mold with their bottoms facing each other in the melting furnace, an arc is generated between these tubes packed without being pressurized to melt the metal scrap. The molten metal thus produced is dropped into a water-cooled mold and solidified. [Detailed Description of the Invention] In this invention for manufacturing ingots from metal scraps, as shown in a side view of the outline of the manufacturing state in FIG.
Scraps 1 of various sizes are packed into a pipe without being sorted or pressurized, and the pipes 2 filled with scraps 1 are placed in a water-cooled copper mold 3 with their bottoms 2a facing each other.
When these are placed horizontally on a water-cooled mold as consumable electrodes and an arc 4 is generated between them, the metal scrap 1 constituting both electrodes melts down into the water-cooled copper mold 3 along with the tube material 2.
A pool of molten metal 5 is formed above the water-cooled copper mold 3, while below it the molten metal 5 is cooled and solidified by the water-cooled copper mold, forming an ingot 6.
form. Although the tube used in this invention may have any shape in cross section, it is usually preferable to use a tube with a circular or square cross section, and the bottom provided at one or both ends of the tube may be This is to prevent scrap from falling out of the pipe when it is filled with scrap and before the pipe filled with scrap is fed into the melting furnace and melted. If so, this bottom part may be of any shape; for example, if the size of the scrap is large enough, it may be shaped like a net, a lattice, or a slit, or may have a through hole formed therein; Although it is usually sufficient to provide the material at one end of the tube, it may be provided at the other end, that is, at both ends, if necessary. After the bottom of the pipe material melts down, some of the scrap packed inside the pipe material may fall into the molten metal pool formed above the water-cooled mold without being melted during the melting operation. Because of their relatively small size, such scrap easily melts in a pool of molten metal heated by a hot arc. In this invention, the number of tube materials to be processed at a time is not necessarily one pair; for example, in order to increase productivity, more consumable electrodes, for example, two or more pairs, may be placed facing each other and these may be similarly melted. The present invention is particularly advantageously applied to the production of ingots from scrap of refractory metals such as titanium, zirconium, or their alloys, but other metal scraps can also be melted by the consumable electrode arc melting method. It goes without saying that the present invention can be applied to any metal scrap that is suitable for this purpose. [Example] Next, the present invention will be explained by referring to an example.
A titanium alloy pipe with a bottom having a composition of Ti-6%Al-4%V and dimensions of 60 mm square x length: 1200 mm x thickness: 1 mm is prepared, and this pipe has the above composition and Titanium alloy scraps of various sizes, ranging from a minimum of 10 mm square to a maximum of 40 mm square, having the same composition are allowed to fall naturally and packed without pressure, and the total weight of the pipe is
The weight was 11.3Kg, and the filling rate was 58%. This 2
As shown in Fig. 1, they were placed horizontally in an arc melting furnace with their bottoms facing each other, and these were used as consumable electrodes under vacuum (2 x 10 ^-3 mmHg).
An arc was generated under the conditions of voltage: 40 V and current: 2000 A, thereby melting the consumable electrode to produce a cylindrical ingot having dimensions of diameter: 115 mm x length: 400 mm. The component analysis values of the scrap used in this example and the obtained ingot were as shown in Table 1.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, in a consumable electrode type arc melting furnace, metal scraps of various sizes ranging from chips to large lumps can be packed into a pipe material without applying pressure. As a consumable electrode, these metal scraps can be melted together, so there is no need to sort metal scraps by size, and
The industrially advantageous effect is that ingots can be produced from metal scrap without any complicated processes such as welding, pressing and crushing.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram drawn from the side to show the main points of the method of the present invention. In the figure, 1... metal scrap, 2... tube material, 3... water cooling mold, 4... arc, 5...
Molten metal, 6... ingots.

Claims (1)

[Claims] 1. In a consumable electrode type arc melting furnace, an electrode made from metal scrap is used as a consumable electrode to melt the metal scrap, and the resulting molten metal is solidified in a water-cooled mold to form an ingot. In the method for producing ingots from metal scrap, bottomed tubes made of the same material as the metal scraps, into which the metal scraps are packed without being pressurized, are placed with their bottoms facing each other in the melting furnace. While held horizontally on a water-cooled mold, an arc is generated between these pipes packed with the metal scrap to melt the metal scrap, and the molten metal thus produced is dropped into the water-cooled mold and solidified. The method for manufacturing an ingot, characterized in that: