GB537164A - Improved method of, and means for use in, welding by the electric arc process - Google Patents

Abstract

537,164. Uniting by fusion. PETERS & CO., Ltd., G. D., and NEEDHAM, R. April 17, 1940. Nos. 6922 and 7310. [Class 83 (iv)] In a method of electric arc welding a flux coated electrode is placed lengthwise in the space enclosed by the walls of the weld metal channel and also by the walls of a longitudinal groove in a backing bar of heat conductive non-welding material which lies against the work parts on either side of the channel and excludes air from the arc and permits escape of gas, the welding proceeding automatically as the welding rod is consumed by melting of its metal core by the arc. In butt welding parts 1, 2, the edges of the parts may be shaped to provide a V or semicircular channel 5 which may be closed or open at the base and a flux coated electrode 6 is placed in the channel and enclosed at its other side in a V-shaped groove in a copper backing bar 7. One end of the electrode is bared and is secured in clamping jaws 10 connected by a conductor 9 to one terminal of an electric circuit and secured to a peg 12 mounted in but insulated from, the bar 7. The arc is struck by a carbon electrode 14 mounted on a pivot 15 secured to, but insulated from, the bar 7. A switch may be provided which may operate to cut off the current automatically when the arc approaches the end of the electrode, being associated with a thermostatically actuated trip means responsive to rise of temperature resulting from proximity to the arc. In forming corner joints, lap joints or T joints, Fig., 8, between plates 1, 2, the bar 7 is substantially L-shaped to provide one side of the enclosed space, the other side being formed by the angle between the parts. Recesses of different sizes may be made in opposite comers of the bar. In another form the recess may formed with lips 16, Fig. 9, for retaining the electrode therein in which case the electrode may be passed through the recess before the bar is applied to the work. The outer surfaces of the bar may be longitudinally grooved or ribbed, filled or checkered &c. to dissipate the heat to the atmosphere and the surfaces which are in contact with the work may be grooved longitudinally to improve the gas seal between the bar and work. In butt welding operations a second heavy bar may be disposed beneath the joint to support or prevent the spread of metal at the underside of the joint and assist in dissipating heat therefrom. The backing bar and/or the underbar may be hollow and water cooled. When making a T- joint dislocation may be prevented by welding along both sides of the joint simultaneously the arcs travelling in the same or opposite directions. Tubes may be butt welded to each other by using curved backing bars and electrodes.