Patent FR-2955794-A1 (FR)
Title: Simultaneously performing non-fusible electrode arc welding of two bars on inner surface of tube, comprises introducing welding cart having welding heads in tube, and positioning welding heads on both sides of the contact area
Inventor: VERDIER GILLES
IPC: B23K9/167
Filed: 2010-01-29
Abstract: The process of simultaneously performing non-fusible electrode arc welding of two bars (11, 12, 14) on inner surface of a tube (1), comprises introducing a welding cart (2) having a pair of welding heads in the tube, and positioning the welding heads on both sides of the contact area between the inner wall of the tube and the bar. The welding cart is displaced along the length of the tube so that the welding heads are simultaneously welded on both sides of the contact area between the inner wall of the tube and bar. The bars are uniformly distributed around inner circumference of the tube. The process of simultaneously performing non-fusible electrode arc welding of two bars (11, 12, 14) on inner surface of a tube (1), comprises introducing a welding cart (2) having a pair of welding heads in the tube, and positioning the welding heads on both sides of the contact area between the inner wall of the tube and the bar. The welding cart is displaced along the length of the tube so that the welding heads are simultaneously welded on both sides of the contact area between the inner wall of the tube and bar. The bars are uniformly distributed around inner circumference of the tube, and diametrically opposite to the inner side of the tube. The welding cart comprises a guiding unit to maintain the bar in a specified position during their storage. The guiding unit comprises a groove formed in a body of the welding cart partially rotating the bar. A bottom of the groove is equipped with a pressure unit pushing the bar into the tube wall. The pressure unit comprises a roller mounted in rotation in the welding cart body and associated to a returning unit. The side wall of the groove is equipped with a unit for positioning the bar. The welding cart is displaced along the tube by welding at the first time the two sides of the contact area between the inner wall of the tube and the bar and at a second time in a different angular position by welding both sides of the contact area between the inner wall of the tube and another bar. The welding cart is moved along the tube by welding the first time the two sides of the contact area between the inner wall of the tube and at least one strip and at least a second time in a different angular position by welding both sides of the contact area between the inner walls. The tube is placed in an upright position during welding, where the welding carriage is moved from top to bottom of the tube for welding. The bar comprises a longitudinal groove (26) on one side to be welded to the inner wall of the tube in which an alloy fiber is welded. The bars are produced by an extrusion process. The welding cart is subjected to a rotational movement relative to the tube axis as it moves along the tube so as to weld the bar by providing a helix inclined to the axis of tube. An independent claim is included for a tube with increased internal structure and made of a refractory alloy.