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Vsesojuzny Nauchno-issledovatelsky Proektno-konstruktorsky I

Arkady Leonidovich Bolotnikov

David Grigorievich Bykhovsky

Alexandr Yakovlevich Medvedev

Yakov Vulfovich Rossomakho

Alexandr Ivanovich Danilov

Gennady Egorovich Strepetov

Viktor N Kiselev

A non-consumable electrode for plasma-arc welding in an atmosphere of carbon dioxide or carbon-dioxide-based mixtures, includes a holder of copper or copper alloys and an active insert of hafnium embedded in the holder, with a hafnium oxycarbide layer disposed on the surface of the insert, the latter also including a graphite layer applied over the hafnium oxycarbide layer. A method of manufacturing the non-consumable electrode includes the steps of joining the holder of copper or copper alloys to the active insert of hafnium, connecting the holder to the negative pole of the power supply, placing the non-consumable electrode in an atmosphere of carbon dioxide, connecting an additional electrode to the positive pole of the power supply with an electric arc struck between the electrodes, forming a hafnium oxycarbide layer on the surface of the active insert at an electric arc current of up to 0.2 I, and subsequently forming a graphite layer over the previously formed hafnium oxycarbide layer as the current is increased from 0.2 I to I at a rate not exceeding 40 amperes per second, where I is the operating current of the non-consumable electrode.

Non-consumable electrode for plasma-arc welding

A method of plasma multiarc welding by permanently burning direct-current arcs of different polarities makes use of a plasma forming gas and shielding mediums and the arcs are located so that the adjacent arcs have opposite polarities, consisting, according to the invention, in that all arcs are started between nonconsumable electrodes and a workpiece or some arcs are started between nonconsumable electrodes and a workpiece and other arcs are started between consumable electrodes and a workpiece, the currents of all arcs and the distance between the arcs being set so that the ratio of the product of the currents of two adjacent arcs to the distance therebetween is equal or more than 6.10.sup.3 A.sup.2 /cm.

Method of plasma multiarc welding by permanently burning direct-current

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Saint-Petersburg, Russia

Arkady Leonidovich Bolotnikov