DE1565269B2 - Device for the production of arc electrodes - Google Patents

Description

F i g. 1 an electrode body under isostatic pressure,

Fig.2 shows an alternative embodiment of the flexible envelope and

F i g. 3 the simultaneous pressing of several electrode bodies.

In Fig. 1 is a device for the electrode manufacture shown according to the invention, which relates to the manufacture of welding electrodes. In a bag 11 is a core wire of low-alloy steel 12 enclosed, which in electrode powder 13 made of aluminum, titanium, ferromanganese, cryolite, alkaline earth metal carbonate and fluorspar is embedded. The bag 11 with its contents is enclosed in a pressure chamber 14 which is filled with a pressure medium. From a pressure generation system 15, e.g. B. from a pump or a compressor, an isostatic pressure is applied exercised the bag with its contents. The pressure must be kept above 1000 atmospheres, advantageously between 2500 and 4000 atmospheres but pressures up to 10,000 atmospheres and higher can also be used. By the isostatic pressure treatment is obtained in whole or in part without the aid of a hydrogen-containing one Binder, e.g. B. water, a homogeneous electrode, which optionally with a subsequent sintering or can be exposed without gas pressure.

The device can also be used to manufacture tubular electrodes. This serves as a resilient sheath the electrode tube made of steel, copper, etc., enclosed in the powdery material is. The tube can be straight or curved, possibly in the form of a coil, for use in automatic welding machines. The tube is sealed at both ends and then the isostatic Exposed to pressure.

The pressure can be applied in the cold state ¹ ; this can only be followed by sintering or a second printing process with heating, in which sintering also takes place, or one can also use the

ίο isostatic pressure at the same time as heating use.

The bag can be provided with a rubber body 16 with several holes 17 for the electrodes (Fig. 2).

Several, possibly a large number of bags with electrodes (FIG. 3) can be enclosed in a pressure chamber and these can be exposed to isostatic pressure at the same time.
In addition to gas or liquid, various solid materials can be used as pressure medium, which are elastic or otherwise compliant or in powder form.

When producing welding electrodes, the powder can be used in terms of its quantity and composition can be varied along the length of the electrode.

In the manufacture of graphite electrodes for electric arc furnaces, the carbon powder is converted into a Bag or some other flexible cover placed in a similar manner, after which the graphitization can be carried out in a suitable oven.

1 sheet of drawings

Claims (1)

1. , ■■■■■■ .. 2 '· - ■ - A disadvantage of these known methods and the Claim: "Powder body produced with it is limited Compaction and the not all-round pressure, where- Device for the production of arcs by not getting any compaction on all sides, Electrodes that do not contain any hydrogen or water release, if necessary a core part can be broken down and thus left no isostatic assign and, moreover, from one with flux, compaction. Adding binders or other additives In the production of, for example, graphite Powdery starting material exist, wel- electrodes for electric arc furnaces and the like. One uses ches under the application of pressure together- io as starting material ground raw coal, which is joined together, characterized by a binding agent, baked together and mixed to compress the constituents (13) in the Pul- is, i.e. with more or less hydrous metallurgy known, the components one or hydrogen containing pitch. The body, which is flexible and baked together under a high pressure, is then closed for the purpose of gray exposable casing (11; 16), with a phitisation as casing being heated to 3000 to 6000 ° C. Despite the bag (11), a rubber body (16), this type of treatment, the electrodes are often not a freely curved tube or, as is known, a straight tube made of hydrogen. Also with other types of. Elek-Rohr are applicable, the use of pressure for an isostatic electrode production comes from ¹ externally closed hydrogen-containing binders with similar disadvantages. 20 share before. Another disadvantage with the usual electrode production is that one does not have a satisfactory f The homogeneity of the electrodes preserves what their burning ^ The invention relates to a device for impairing properties. place of arc electrodes that do not contain water. The object of the invention is to develop a Release substance or water vapor, possibly a device with the arc electrodes of the one-core part have and can also be made from a type mentioned above, the Flux, binders or other additives ye.rv: without the use of organic binders only under Put powdery starting material, the application of pressure creates a homogeneous and uniformly soft structure of the powdery structure that is compacted together with the application of pressure is. material and neither water vapor Covered welding electrodes are usually also given off hydrogen. made so that on one. Core wire with relative. The device according to the invention is characterized by a moderately low Dnirisk irr one or more ^{: It is} characterized by the fact that it is used to compress the pressure directions of the electrode casing in moist components in powder metallurgy - for example, pressed on from the state and then the casing through USA. Patent specification 2 725 288 - known, the heating essentially of the water-containing constituents, resilient and contains a binding agent of the plasticizing agent or the high-pressure shell, with the water content of other additives of the shell freed shell a bag, a curved tube or such will be served. A disadvantage of this method is that the water 40 is known, a straight pipe can be used, which is not completely removed from all sides of the hydrogen contained in certain connections of the jacket by isostatic pressure from the outside. The shape of the shell and its and other properties of water during welding allow that one gets isostatic, material content in the weld metal, which can be harmful and can be pressed under heating, where below ν is, especially in the case of ljpch-resistant, more, or j 45 other wintering takes place. One also avoids less high-alloy steel. ^; the mixing of harmful additives in the It is also already known to produce encased welding powder mass, since their compaction on mechanical electrodes, wherein the electrode casing can be achieved nischem way, ie by pressing a. Mass used as plasticizing, isostatic pressing. The all-round pressure, which is formed by means of at least one organic substance at -5 ° with the aid of gas or liquid as a pressure medium of high viscosity, is formed and obtained in such a way that the bag or the tubes are dried out that no organic, in the can set, pressing the weld metal together on all sides causes pore formation. effecting sub- the enclosed powder and the other ingredients remain (Swiss patent specification constituents, and you get a very homogeneous and 299 790). A chemical way of doing this has succeeded in avoiding hydrogen brittleness, a permanent electrode with good burning properties, which is a result of me and without hydrogen content.
chanical way has not yet been reached. The device can be used to manufacture conventional One has also used in the manufacture of powder Licher electrodes, such as. B. from For atomic reactors these bodies are made by means of gas welding electrodes with a shell containing a powder at a certain pressure and embedded in a 60 alloy additives, flux, reducing agent, outer powder coating, which is surrounded by a sheath containing binders, etc., with the advantage of he, - .. is, compacted, whereby one is mainly interested in the higher homogenization and thus the better Side of the body a certain lower grain burning properties is obtained; also let yourself paktierung with simultaneous degassing of the contents with her graphite electrodes for electric arc furnaces. You have to put the powder body at the same time 65. ν heated to sintering temperature. It is in principle in the drawing is an example of Ausauch known, instead of gas, a liquid pressure conduction of the device according to the invention is used apply. posed, it shows