GB842120A - Method and apparatus for butt welding elongated metal members - Google Patents

Abstract

842,120. Welding by pressure. COMBUSTION ENGINEERING Inc. May 16, 1957 [June 22, 1956], No. 15558/57. Class 83 (4). In butt - welding elongated aligned and abutted metal members by heat and pressure, the members are tied together by tie means applied at two anchor-points on the members at points spaced from the abutting ends and either allowing the heated ends of the members to expand between the anchor points due to the welding heat alone to urge the abutted ends together or applying supplementary heat to the end portion of at least one of the members to cause additional expansion thereof or applying heat to the tie means to expand them before and during the time when they are applied to the anchor points and allowing the tie means to cool and contract to additionally urge the ends together. Tube ends A, B, e.g. of carbon or chromium steel, are machined clean and provided with cardboard baffles 24 before being mounted with their ends spaced in clamps 10, 12 engaging welded projections on the tubes, the clamp 10 being fixed to the base 15 and clamp 12 being slidable on rods 16 and tie-bolts 34, 36 being provided between the clamps. A hollow water-cooled induction coil C in separable halves is placed about the spaced ends and a two-part housing 26 connected to a source of inert or other protective gas is provided to enclose the coil. Gas is supplied to the housing, the ends are abutted by tightening nuts 37 on the bolts and thereafter current at 3-10,000 kc. per sec. is supplied to the coil C to heat the ends. To obtain the welding pressure the heat conducted from the heated ends may be used to expand the tubes or electrical heating windings 38, 40 of insulated resistance wire about the tubes are energized to heat and additionally expand the tubes. One of the windings may be omitted. In another method electrical heating windings 44, 46 about the tie-bars are energized to heat and expand the bolts before the clamp nuts 37 are tightened to abut the tube ends and the bolts are cooled and contracted by blowing air thereover or by passing water therethrough if they are hollow. The heat supplied by the inductor is continued for minutes after the weld has been made. Bars may also be welded and tube end heating other than by induction may be employed and gas jets may replace the coils 38, 40. U.S.A. Specification 2,542,393 is referred to.