GB795481A - Stud welding - Google Patents

Abstract

795,481. Welding by pressure. AIR REDUCTION CO., Inc. Nov. 15, 1955 [Nov. 15, 1954], No. 32679/55. Class 83 (4). In stud-welding the arc is shielded with an inert monatomic gas, with mixtures of such gases or with such gases having small additions of active gases and a substance is added to the arc comprising one or more metals selected from the group consisting of the alkali metals, the alkaline earth metals, lanthanum and lanthanum series rare earth metals, actinium and actinium series rare earth metals, scandium and yttrium, and/or one or more compounds which partially or wholly dissociate in the arc to liberate such metals. A stud 16 which may be of aluminium, copper, nickel, iron, magnesium, titanium or alloys of these, with the substance applied thereto, e.g. on the surface of its head, is held in the slotted chuck 14 on a magnetic plunger 12, reciprocable within a solenoid 33 in the stud-welding gun 11. A metal sleeve 21 provided with a porcelain ferrule 22 is spring-urged to abut the workpiece during welding. Inert gas, e.g. helium or argon is supplied from a cylinder 24 through an electrically-controlled valve 27 to the sleeve 21 to pass through the ferrule on to the work. In operation the ferrule is placed against the work, a trigger 32 is actuated to open the valve 27 and solenoid 33 is energized to retract the stud. Simultaneously the current which may be alternating is supplied to the stud and to the workpiece through the legs 31 of the gun. The ferrule 22 may be omitted. The metals may be added to the arc in elemental or metal form or as compounds, e.g. oxides, carbonates, borates, phosphates, nitrates, silicates or halides. Mixtures of two or more of the elements and/or compounds may be used. Preferred addition materials are cesium nitrate, rubidium carbonate, cesium-rubidium chloride, barium oxide or carbonate, barium-strontium mixtures in the form of oxides or carbonates, lanthanum and lanthanum series rare earth mixtures in metallic and oxide forms and potassium carbonate. Specifications 731,836 and 738,284 are referred to.