JPH0331771B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to the refining of metals such as titanium alloys, which must be free of any unrefined inclusions, in an electron beam cold furnace, and more particularly to More particularly, it relates to a new and improved electron beam cold smelting furnace configured to prevent contamination of refined metals.

Prior Art When a metal such as a titanium alloy refined by electron beam cold furnace refining is used in an aircraft engine part, the refined ingot contains extremely small amounts of unrefined inclusions. will also incur severe damage. Such inclusions must be completely eliminated, as they lead to destruction and decomposition, for example, in aircraft engine parts that rotate at very high speeds.

Conventionally, when refining metals such as titanium alloys in beam cold furnaces, processed titanium alloy cuttings made of chunks or pieces of titanium sponge or scraps obtained from manufacturers of titanium alloy parts are placed in a water-cooled furnace. I'm putting it in. The material is fed by gravity at one end of a cooled elongated hearth in the electron beam furnace, and the impact of the electron beam within the furnace melts and refines the material. This refined molten material is injected into a cylindrical mold from the opposite end of the hearth to form vertically oriented cylindrical ingots which, when solidified, are drawn downwardly from the mold. .

In conventional electron beam cold furnaces used for refining titanium alloys and the like, the raw material often contains evaporable contaminants such as chlorine in the titanium sponge and oil or moisture in the processed cuttings. When such materials are introduced into the melting region of the furnace and heated by the molten metal and the electron beam, vaporizable contaminants often cause a relatively violent injection into the molten metal being refined.
It has been found that when such jetting occurs, both molten and unmolten material from the molten region is sputtered toward other regions of the electron beam furnace, including the casting region where the ingots are smelted and molded. As a result, unrefined metals containing undesirable inclusions, such as titanium nitride and tungsten carbide, can enter the mold and produce cast ingots and finished products formed from ingots, such as jet engine compressor disks. It is possible that it is included in

In the past, it has been proposed to provide a vertical shield over the molten material at the end of the furnace adjacent to the casting area in order to prevent material from sputtering into the mold in this way. ing. However, in such a configuration, the unmelted material sputtered by the jet and prevented by the shield from directly entering the casting area is deflected downwardly from the shield and at the point where it passes from the furnace to the mold. It will enter the molten material. Furthermore, the evaporated material and the sputtered molten material deposit and solidify on the shield, and the portion of such solid material containing contaminant inclusions is removed from the smelted molten material from the shield as it is passed from the furnace to the mold. will fall to.

It is therefore an object of the present invention to provide a new and improved electron beam cold furnace refining arrangement that overcomes the above-mentioned drawbacks of the known art.

Another object of the present invention is to provide a new and improved electron beam cold smelting furnace that substantially ensures that the refined metal is free of undesirable inclusions.

SUMMARY OF THE INVENTION These and other objects of the present invention provide for furnace sections extending at an angle to each other, a feeding device for introducing raw material into the melting zone at one end of one furnace section, and a feeding device for introducing raw material into the melting zone at one end of one furnace section, a mold for receiving refined material from opposite ends of the furnace; and a shield positioned at an angle between the furnace compartments, the shield being arranged at an angle between the melting region and the mold so that a straight line extending between the melting region and the mold is laterally disposed from both furnace compartments. This is accomplished by providing an elongated furnace arrangement with a shield disposed intersecting the shield at spaced apart locations. In a preferred arrangement, the two furnace sections are separate furnaces arranged at different levels and at right angles to each other, and the refined molten metal from the first furnace is injected into adjacent ends of the second furnace. configured so that

Further objects and advantages of the present invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings.

EXAMPLE In the conventional cold furnace electron beam refining arrangement shown in FIG. 1, a furnace 10 includes a hearth 11 containing cooling pipes 12 for circulating water or another cooling liquid. At the inlet end of the furnace, the chute 13
feeds a piece of raw material 14 to be refined, such as a titanium sponge or a titanium alloy working cutting, towards the furnace, and a series of electron beam guns 15 placed above the furnace emit a controllable electron beam 16. and these beams can be directed to desired areas of the furnace to heat the material to be refined in the desired manner. One of the beams 16 is focused on the raw material 14 in the melting region 17 of the furnace to melt the raw material, and the other electron beam 16 directs the molten metal from the melting region 17 to an injection lip 18 at the other end of the furnace. controlled to refine the molten metal in between.

As a result, the raw material introduced into the furnace forms a molten pool 19 which flows from the melting zone 17 to the lip 18. Since the hearth 11 is cooled by the liquid flowing in the pipe 12, a solid skull 20 of the molten material 19 of the weld pool forms on the inner surface of the hearth, preventing the hearth from being degraded by the molten material. .

The molten material 19 is completely melted and refined as it flows through the furnace, forming a stream 21 of molten and refined material. This is injection lip 1
8 into a vertical mold 22 containing cooling pipes 23. The molten material cools in mold 22;
An ingot 24 is formed. The ingot is
It is gradually moved downwards through the mold in a conventional manner as indicated by the arrows. Another electron beam gun 25 is
The electron beam 26 is directed in a controlled manner onto the surface of the molten material 27 in the mold to form an ingot 2.
1. Control the cooling and solidification to 1 in the desired manner. Of course, the entire arrangement is housed within a sealed enclosure (not shown) and maintained under high vacuum in the usual manner.

When the raw material 14 is introduced into the melting zone of the furnace, it often carries with it certain contaminants, which are volatile at the temperature of the molten material 19 and are therefore not present during the refining process. will be removed. For example, titanium sponge particles may contain chlorine, and when titanium alloy cuttings are injected from chute 13 into melting region 17, liquids such as oil or water may be entrained with these cuttings. There is. If such volatile materials are included in the molten material 19, they will rapidly evaporate at or below the surface of the molten material, creating a jet. These jets sputter molten and non-molten material in all directions.

In conventional furnace configurations, such injection sputters unrefined material directly from the melting region 17 of the furnace toward the mold 22, as shown by dotted line path 28 in FIG. The electron beam gun 25 directs an electron beam 26 onto the surface of the molten material 27 in the mold, which is generally at a lower temperature than the material in the furnace, and the electron beam 26 is unable to refine the unrefined material in the mold. It is insufficient. As a result, sputtered unrefined metal containing inclusions such as titanium nitride and tungsten carbide may be included in the ingot 24, contaminating and having a detrimental effect on the final product formed from the ingot. affect

In a certain conventional electron beam cold furnace device,
A shield is placed over the outlet end of the furnace, as shown by dotted line 29 in FIG. 1, to prevent material sputtered from the molten region from passing directly into mold 22. However, in such a configuration, unrefined material that is sputtered from the molten region 17 toward the mold and hits the shield 29 is deflected downwardly onto the surface of the molten material 19 being poured into the mold and is mixed with the molten material. It is often fed directly into the mold. Furthermore, the evaporated material and sputtered molten material solidify on the surface of the shield, and a portion of such solidified material may become dislodged and fall directly into the molten material being injected, causing the same harmful effects. results.

According to the invention, the possibility of introducing such unrefined material into the mold is eliminated by providing a compartmentalized furnace as shown in FIG. In this configuration, the first furnace section 30 is in the form of an elongated furnace with an inlet end, and the raw material 14, such as titanium sponge or titanium alloy cuttings, is introduced from the chute 13 into the melting region 17 at the inlet end. An electron beam gun, not shown in FIG. 2, which is similar to gun 15 shown in FIG.
The molten material 31 being fed towards the injection lip 32 at the outlet end of the furnace section 30 is refined. A second elongated furnace section 33 is positioned at a lower level and perpendicular to the first furnace section 30 and receives molten material 34 from the injection lip 32. One or more additional electron guns similar to gun 15 of FIG. 1 but not shown in FIG. 2 direct an electron beam onto the surface of the molten material in the refining region 35 of this furnace section; The material flowing through this furnace section completes the smelting. The furnace section 33 has an injection lip 36 at its outlet end through which the refined molten metal 37 is poured into a mold 38 and a first
A refined ingot is formed in the same manner as described above for the figure. The mold 38 is circular in cross-section, as shown in FIG. 2, but may have any other desired shape, such as rectangular, for example.

According to the invention, a solid shield 39 is installed at an angle between the first furnace section 30 and the second furnace section 33 in order to prevent unrefined material from being introduced into the mold 38. The shield 39 is intersected by a straight line connecting the melting zone 17 at the inlet of the furnace 30 and the refining zone 35 or mold 38 of the second furnace section. Furthermore, as shown in FIG.
9 is laterally offset from the furnace compartment so that the molten material sputtered towards it or the evaporated or sputtered material solidified on its surface also flows into the molten material of the first furnace compartment 30. The melted material in the second furnace section 33 is also prevented from falling. Although only two furnace compartments are shown in Figure 2, any number of furnace compartments may of course be used, as long as a shielding arrangement is provided to prevent material sputtered from the melting region from reaching the mold. Good too.

Advantages of the Invention This configuration allows the introduction of materials containing vaporizable contaminants into the melting zone of the furnace, such as titanium alloys, without the risk of such inclusions sputtering into the mold at the end of the furnace. metals can be refined in an electron beam cold furnace apparatus. Furthermore, when two or more furnace sections are used at different levels, as is the case in the embodiment shown in FIG. occurs in each furnace compartment regardless of the status of other furnace compartments. As a result, different smelting conditions can be applied to each furnace section, which improves the agitation of the material being smelted by cascading the molten material from one section to another. The degree of refinement of materials can be improved.

Although the invention has been described with respect to specific embodiments, many changes and modifications will become apparent to those skilled in the art. It is therefore intended that the following claims cover all such changes and modifications that fall within the scope of this invention.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing a conventional electron beam cold furnace refining structure, and FIG. 2 is a schematic plan view showing a typical electron beam cold furnace refining structure according to the present invention. It is. 10...furnace, 11...hearth, 12...cooling pipe, 13...chute, 14...piece of raw material, 1
5,25... Electron beam gun, 16,26... Electron beam, 17... Melting area, 18... Injection pipe, 19... Molten pool, 20... Skull, 22,3
8... Mold, 24... Ingot, 29, 39...
Shield, 30...first furnace section, 31...molten material, 32, 36...injection lip, 33...second
Furnace section, 35... Refining area.

Claims (1)

Claims: 1. Furnace means comprising first and second elongate furnace sections disposed at an angle to each other, and a mold for receiving molten material after passing through the first and second furnace sections; feeding means for introducing the material to be refined into the melting zone near one end of the first furnace section and flowing the molten material between the opposite end of the first furnace section and one end of the second furnace section; means for transferring refined material from the opposite end of the second furnace section to the mold;
shielding means disposed between the melting region of the first furnace section and the mold, wherein a straight line extending between the melting region of the first furnace section and the mold is laterally separated from the first and second furnace sections; 1. A refining furnace of an electron beam type, comprising: a shield means disposed to intersect with the shield means at a position where the electron beam refining furnace is exposed. 2. The method of claim 1, wherein the first furnace compartment is at a higher level than the second furnace compartment, and the connecting means comprises an injection lip at the end of the first furnace compartment adjacent to the second furnace compartment. The electron beam type refining furnace described. 3. Second, the furnace section includes a smelting region, and the shielding means is such that a straight line extending between the melting region of the first furnace section and the smelting region of the second furnace section is located between the first and second furnace sections. 2. The electron beam type refining furnace according to claim 1, wherein the electron beam refining furnace is arranged so as to cross the shielding means at a position laterally away from the compartment. 4 the first and second elongated furnace sections are arranged substantially at right angles to each other, the melting region of the first furnace section being at the end of the section remote from the second furnace section;
The mold is positioned near the end of the second furnace section remote from the first furnace section, and the shielding means is positioned at an angle formed between the first and second furnace sections. The electron beam type refining furnace according to claim 1. 5. The first and second furnace sections are configured to pass molten material under different refining conditions.
Electron beam type refining furnace described in .