Showing papers on "Butt welding published in 1968"

Analysis of thermal stresses and metal movement during welding

Abstract: Finite element computer programs were developed to determine thermal stresses and metal movement during butt welding of flat plates and bead-on-plate welding along the girth of a cylindrical shell. Circular cylindrical shells of 6061 aluminum alloy were used for the tests. Measurements were made of changes in temperature and thermal strains during the welding process.

Method and apparatus for resistance welding

Abstract: 1,234,228. Welding by pressure. CONTINENTAL CAN CO. Inc. 1 Jan., 1969 [28 Feb., 1968], No. 136/69. Heading B3R. [Also in Division H2] In electrical resistance welding an alternating current is supplied to the electrodes in contact with the work, of such a frequency that the reactance of the welding current circuit including the electrodes and the work is higher than the resistance of the circuit. An apparatus for making metal blanks 11 into tubular cam bodies comprises a horn 12 and advance means 13 for moving the blanks 11 along the horn and an apparatus 14 for forming the blanks into tubular shape encircling the horn with overlapping edges. Roller electrodes 18, 24 are provided to contact between them the edges to be welded, although sliding or shoe electrodes may be used. The roller is mounted on a fluid piston/cylinder device 30, 31 so that the roller 24 is pressed tightly to sandwich the edges to be welded. Alternating current is supplied from a generator 35 including a step down transformer to the electrodes 18, 24 and a tack welder including electrodes 37, 38 may be provided to tack weld the overlapping edges prior to insertion between the electrodes 18, 24. The circuit from the generator to the edges to be welded includes the resistances of the rollers, of the connectionof the rollers to their leads (the constant resiss tances R) the resistances at the contacts of the rollers with the edges, of the edges and of the interface between the edges (the varying resistances RV) and includes the inherent self inductance of the circuit and the inductance or capacitance of an inductor or capacitor included in the circuit. In Fig. 5, the ohmic resistance of the circuit is presented by Rt=Rv+R and the ohmic reactance is represented by XL. The frequency of the generator 35 supplying sinusoidal or square wave current is selected so that the ohmic reactance XL is higher than the ohmic resistance Rv so that the varying resistance Rv has little effect on the current passing between the electrodes being determined by the impedance Z=#Rt 2 +XL 2 . It is stated that the edges may be butted instead of lapped and may be of separate sheets, also that the welding may be spot or butt welding.

Stud welding control circuit

Abstract: A solid state control circuit and alternating current power sources for stud welding apparatus are provided. The power sources include three-phase power for the pilot arc and single-phase power for the welding arc. The controls for stud welding apparatus where such power sources are utilized would be expected to be quite complex and costly. The controls according to the instant invention, however, are relatively simple and substantially no more involved than those heretofore employed with welding equipment using capacitors as the welding arc power source.

A machine for butt welding

Abstract: 1,128,412. Welding by pressure. INSTITUT ELEKTROSVARKI IMENI E.O. PATONA. 19 Aug., 1966, No. 37270/66. Heading B3R. A machine for pressure butt welding the ends of a workpiece to form an article, e.g. a ring &c., comprises a stationary head, a movable head connected to the stationary head by an upsetting drive and a band which embraces the workpiece, the band being connected at one end to the stationary head and at the other end to the movable head. The stationary head 2 is mounted on a bed 1 and rods 5 secured to the head 2 at one end and to an upright 6 on the bed at the other end carry pistons located in hydraulic cylinders 4 secured to the movable head 3. A band 8 is connected to the heads 2, 3 by articulated joints comprising journals 9 in bearing 10 arranged in sockets in the heads. The bearings 10 are provided with radial adjustment means 12, 13 and means to adjust across the width of the machine. A transformer 15 is connected to the ends of the band, the band being provided with copper current supply plates 16. In a modification, the movable head moves in an arc with its centre near the geometrical centre of the workpiece and the ends of the band are rigidly fixed to the heads by bolts. In operation, to flash butt weld the ends of ring 7, the movable head is withdrawn from the fixed head, the ring to be welded is placed in the band with its ends spaced and the welding transformer is switched on. The heads are brought together and pre-heated and are finally abutted and upset. The movable head is backed away and the welded ring removed. It is stated that an inductor, gas burners &c. may be used to provide pre-heating and that resistance or cold welding may be effected.

Development of flux covered electrodes for welding 18% ni-co-mo maraging steel.

Abstract: : The development and testing of a flux covered electrode suitable for welding 18% Ni-Co-Mo maraging steel is described. A special flux has been developed to ensure low silicon pick-up in the weld bead, due to the reduction of silicates in the flux by titanium, and adequate titanium recovery. Tensile and impact tests have been carried out on butt welds produced in 3/16 in. thick sheet and on all-weld-metal test pieces produced by butt welding 3/4 in. thick material. Ageing for 3 h at 480C. produced tensile strengths of 96.65 tonf per sq. in. with impact values of about 10 ft-lb. From side fillet welds shear strengths approximately 0.4 of the tensile strength were obtained. Extensive radiography shows that sound welds can be produced over the range of thicknesses investigated. Adjustments in the core wire composition to obtain an electrode more suitable for use with the 90 tonf per sq. in. grade of maraging steel are suggested. (Author)