An apparatus for friction stir welding, a weld tool for friction stir welding, and a method for making a weld tool for friction stir welding are presented. The weld tool comprises a tungsten-based refractory material. A method for manufacturing an article, where the method comprises providing the apparatus for friction stir welding, and the article produced by this method are also presented.

Apparatus and method for friction stir welding of high strength materials, and articles made therefrom

The invention relates to an emissive element for supporting an electric arc in a plasma arc torch using an oxygen gas to create the plasma. The element includes a body having a front face for supporting the electric arc which is defined by at least two distinct components formed from different materials. The first component is an emissive material having a low work function for readily emitting electrons in support of the arc and being reactive with the oxygen plasma gas to form an oxide during an operation of the torch. The oxide forms an electrically resistive layer on the front face of the body upon cooling subsequent to the operation of the torch. Hafnium is a preferred material for the first component. The second component comprises a conductive material having an electrical conductivity greater than the oxide layer for supporting the arc during the initiation of a subsequent torch operation at least until the oxide reaches an operating temperature. Silver and copper are preferred materials for the second component. The conductive material provides a conductive path which allows the arc to be supported thereon until the oxide layer reaches an operating temperature, thereby preventing thermal cracking and removal of the oxide layer. Accordingly, electrode start erosion is reduced.

Electrode with emissive element having conductive portions

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

The invention provides an electroslag welding flux that is especially useful for welding copper-nickel alloys. The electroslag flux contains by weight percent 50 to 95 fluoride compound, 0 to 45 oxide compound, 1 to 25 rare earth-containing material, 1 to 45 potassium-containing material and 0 to 25 metallic. Advantageously, the flux contains by weight percent 60 to 90 fluoride compound, 5 to 40 oxide compound, 2 to 20 rare earth material, 1 to 20 metallic, 2 to 35 potassium-containing material, 0 to 15 carbonate and 0 to 35 binder. Most advantageously, the flux contains by weight percent 65 to 90 fluoride compound, 5 to 35 oxide compound, 2 to 15 rare earth-containing material, 1 to 15 metallic, 3 to 35 potassium-containing material, 0 to 5 carbonate and 1 to 35 binder.

Electroslag welding flux

A non-consumable electrode for use in arc and plasma devices in an inert gas atmosphere comprising a holder and an active portion made of a refractory metal with emission admixtures, the active portion being connected with the holder so that its outer side surface is exposed to a height exceeding 1/4 of a diameter thereof.

Non-consumable electrode

A melt-resistant, reliably performing electrode for low-power electric arcs composed of a high-melting metallic substance, such as tungsten or thoriated-tungsten, having at least the welding tip thereof coated with a layer of high-melting metal-nonmetal compound, such as metal oxides, carbides or nitrides, i.e., thorium dioxide, hafnium carbide, tantalum nitride, etc. The process for producing such an electrode is also disclosed.

Rudolf Klar Dipl-Ing Dr

Papers

Melt-resistant welding electrodes

Nichtabschmelzende Elektrode fuer Lichtboegen kleiner Leistung