DE678084C

DE678084C - Method of flame cutting with an electric arc

Info

Publication number: DE678084C
Application number: DEE43781D
Authority: DE
Original assignee: ELIN A G fur ELEK SCHE IND
Current assignee: ELIN A G fur ELEK SCHE IND
Priority date: 1932-11-21
Filing date: 1933-01-10
Publication date: 1939-07-08

Description

Es ist bekannt, eine als Stromschleifstück ausgebildete Elektrode zur Vorwärmung des durch Sauerstoffstrahl zu durchschneidenden Metallstückes zu verwenden. Es erfolgt ein Stromübergang vom Stromschleifstück zum Werkstück, so daß eine Erwärmung der Berührungsstelle durch den Übergangswiderstand stattfindet. Der örtlich eng begrenzte Teil der Oberfläche wird auf' solche Temperatur gebracht, daß der Sauer stoff strahl die Verbrennung des Metalls einleiten kann. Bei einer Ausführungsform dieses Verfahrens diente die Elektrode gleichzeitig als Düse für den Sauerstoff, bestand aus Kupfer und wurde durch fließendes Wasser. gekühlt.It is known to use an electrode designed as a current wiper to preheat the to use a piece of metal to be cut through by an oxygen jet. There is a Current transfer from the current collector to the workpiece, so that the point of contact is heated takes place through the transition resistance. The locally limited Part of the surface is brought to such a temperature that the oxygen radiates the Can initiate combustion of the metal. In one embodiment of this method if the electrode also served as a nozzle for the oxygen, it was made of copper and was by running water. chilled.

Die Erfahrung hat nun gezeigt, daß es in vielen Fällen schwierig ist, das Schleifstück, durch das ein Strom von einigen hundert Ampere auf das Werkstück übergeht, und insbesondere die Düsenöffnung reinzuhalten und daß die Abnützung in vielen, Fällen unerwünscht groß ist. Eingehende Versuche haben die Möglichkeit ergeben, mit einem viel kleineren Strom zu arbeiten, wenn die wassergekühlte Kupferelektrode dauernd in einem kleinen Abstand vom Werkstück gehalten wird, so daß ein Lichtbogen- entsteht ,und der Lichtbogen magnetisch beeinflußt wird.Experience has shown that in many cases it is difficult to through which a current of a few hundred amperes is transferred to the workpiece, and in particular to keep the nozzle opening clean and that in many cases the wear is undesirably great. Incoming attempts have shown the possibility of working with a much smaller current if the water-cooled copper electrode kept at a small distance from the workpiece is, so that an arc occurs, and the arc is magnetically influenced will.

Es ist zwar bekannt, daß man mit dem elektrischen .Lichtbogen sowohl ohne als mit Verwendung eines Sauerstoffstrahles Metalle schneiden kann. Mit beiden Verfahren konnten aber keine glatten Schnittflächen erzielt werden, so daß sie mit den durch ein Sauerstoff-Acetylen-Gemisch erreichbaren Schnitten nicht wettbewerbsfähig waren. Als Elektrode für das Schneiden mit dem Lichtbogen wurde bisher eine Kohle oder ein-Eisendraht bzw. Metallstab verwendet. Die Anwendung einer Elektrode .und daneben einer Sauer stoff düse hat naturgemäß, besonders beim Schneiden von Kurven" und Ecken, erhebliche -Nachteile gegenüber einer einzigen Düse (beim Acetylen-Sauerstoff-Schneiden), aus der gleichzeitig die Flamme und der Sauerstoffstrahl entweicht.It is known that with the electric .Lichtbogen both without and with Use of a jet of oxygen can cut metals. Both methods could but no smooth cut surfaces can be achieved, so that they are with the by an oxygen-acetylene mixture achievable cuts were not competitive. Used as an electrode for cutting with the electric arc previously used a carbon or an iron wire or metal rod. The application of a Electrode and next to it an oxygen nozzle Naturally, it has considerable disadvantages, especially when cutting curves and corners compared to a single nozzle (for acetylene-oxygen cutting), from which the flame and the oxygen jet escape at the same time.

Andererseits findet man auch Verfahren zum Schneiden mittels des elektrischen Lichtbogens, der von einer allenfalls durchbohrten und als Sauerstoffdüse dienenden Elektrode auf das Werkstück gezogen wird. Da man aber bisher nur daran gedacht hat,, das Schneiden als Hilfsmittel zum Abwracken, also zu Zerstörungsarbeiten zu verwenden, so spielte ein ungleichmäßiger, zackiger Schnitt weiter keine Rolle. Dieser ungleichmäßige Schnitt war bei diesen Verfahren durch das ungleich-On the other hand, there are also methods of cutting by means of the electric arc, that of an electrode that may be pierced and used as an oxygen nozzle is pulled onto the workpiece. But since one has only thought of it so far, the cutting to be used as an aid for scrapping, i.e. for destruction work, so played an uneven, jagged cut does not matter. That uneven cut was in these proceedings due to the unequal

Claims

moderate burn-off of the electrodes caused, which was again due to the fact that no thought was given to the cutting. to cool the electrode effectively. Especially with carbon electrodes, which have been used to a great extent, notches easily develop in the nozzle mouth, which immediately result in a rough cut. In addition, the rapid burn-up of the carbon under the action of oxygen has ruled out the economic viability of electrical cutting. Even the attempt to line the bore in the coal with a copper sleeve was not successful because the mouth of the copper sleeve quickly misplaced. According to the invention, an electrode made of a nonmagnetic metal, preferably copper, is used, which is drilled at the same time serves as oxygen nozzle, which by flowing further by themselves or the electrode holder liquid is cooled _s and has a magnetic influence of the arc. Only through the simultaneous presence of the features described does a flawless, economical process on a par with oxy-fuel cutting results.

One uses as a carrier of the magnetic lines of force, for example, a water vessel serving outer iron sleeve with a tapered end and a hole through through which a copper rod serving as an electrode passes, either soldered or slidable, with appropriate gasket applied. There is a coil over the iron sleeve pushed either in series with the arc or to any power source is switched and influences the direction of the arc in the desired manner. The soaking of the cooling water between the sleeve and the electrode can be made that the ^ magnet coil is also effective cooled, possibly flushed with water immediately, even with suitable insulation,

so that high current density can be used and the coil itself as a calming resistor serves for the arc. Experiments with drilled round copper bars from 5 to over 15 mm outside diameter and with iron sleeves that 'run through coils from 100 to over 3000 ampere-turns were magnetized, have shown that you can with * a Arc voltages of a little over 20 volts and currents of .30 to over 100 amps are sufficient Thermal effect on plates of 10 up to 40 mm thick, so that the oxygen jet gave a smooth cut surface and the cooled copper rod is nowhere strongly attacked became.

The method described has the advantage over cutting with fuel gas the elimination of the risk of explosion.

The voltage and amperage necessary to perform the procedure, can be from an ordinary, for arc welding used dynamo machine, which is a great practical Advantage. It is therefore not necessary in a welding workshop set up for electric welding, a special one To install a transformer or a special dynamo machine for cutting.

Process for flame cutting with an electric arc, marked by applying the following measures at the same time:

a) Use of an electrode made of non-magnetic metal, - preferably Copper,

b) Design of this electrode as an oxygen nozzle by means of a bore,

c) Cooling of the electrode by itself or the electrode holder liquid flowing through.

d) magnetic influence on the arc.