METHOD OF SPOT ELECTROCONTACT WELDING OF ALUMINIUM AND ITS ALLOYS Russian patent published in 2009 - IPC B23K11/18 

FIELD: technological processes.

SUBSTANCE: invention is related to welding, in particular to method of spot electrocontact welding of aluminium and its alloys and may find application for welding of rolled sheet and current distributor buses. Method includes application of stringent welding modes with current density reaching 1600 A/mm² and specific pressures of up to 150 MPa with preliminary treatment of welded surfaces from aluminium oxide film. In order to confine heat release in contact during welding of plates with thickness of 3-12 mm, steel low-carbon foil is installed between them with thickness of 0.05 - 0.2 mm. During one cycle of welding from 1 to 9 pulses of welding current are passed with duration of 0.1 - 0.25 s, with heating of steel low-carbon foil up to temperature of 1200°K. In pauses between pulses that amount to 0.5-20 s, external surfaces are intensely cooled until foil temperature becomes 820°K. Diametre of electrodes D_e, mm for spot welding is assumed as equal to D_e= (1.5δ + 5), where δ is thickness of welded plates, mm; with distances between points of 2D_e and radius of spherical contact surface of electrode R=(100-200), mm.

EFFECT: welded joint of high strength and electric conductivity is produced.

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