Patent GB-440428-A (GB)
Title: Improvements in or relating to methods and apparatus for welding
IPC: B23K9/025
Filed: 1934-06-27
Abstract: 440,428. Welding tubes. MIDLAND STEEL PRODUCTS CO., Madison Avenue, Cleveland, Ohio, U.S.A.-(Assignees of Riemenschneider, E.) June 27, 1934, No. 19015. Convention date, July 14, 1933. [Classes 83 (ii) and 83 (iv)] [See also Group XI] Uniting by fusion.-Metal members such as the longitudinal seams of tubes are fusion welded by moving the members with spaced apart edges, melting the edges by atomic hydrogen jets during the movement and moving the edges towards each other so that the liquid metal forms a bridge which is maintained by the surface tension of the liquid metal without any other support. The open seamed tube is fed from the tube forming mill under a series of atomic hydrogen or other gas arcs 23 which are arranged with their pairs of electrodes 24 at an angle to the seam, Fig. 10. The vertical edges of the seam are progressively melted from the upper edges downward to form a long narrow pool by the low-velocity gas projecting through the cleft, the liquid metal clinging to the edges by surface tension. The action of the first arc in melting the upper corners of the seam is shown in Fig. 12. The edges are progressively pressed together by rolls 33 so as to form an unsupported bridge of liquid metal in the seam until the lower edges of the seam, which may be in a plastic condition and are covered with liquid metal, abut each other or are pressed against each other so as to upset the edges, Fig. 17. The rolls 33 may co-operate with rolls 53, 54 and with a mandrel having rolls 47, 50, the rolls 50, 54 being grooved to receive the upset metal, which may be rolled down by a pair of rolls co-operating with a roller carried by the mandrel. The roll 54 may be integral or divided. The gas supply to the atomic are apparatus may be along the electrodes or separate nozzles 25<1> surrounded by annular parts supplied with lower velocity gas may project the gas between the electrodes, Fig. 12. The electrodes of each pair may be arranged on opposite sides of the seam as shown in Fig. 10, or central pairs of electrodes F, Fig. 4, may be used together with pairs of electrodes such as E <1>, E<2> in which the electrodes of the pairs are on the same side of the seam. The arcs may be held in position by an electromagnet 26 carried by the mandrel. The open seamed tube is first passed through a throat 39 having a seam-engaging rib 42 and a pair of screw-operated tube compressing jaws 43, so as to engage the edges of the tube with the rib 40 of a spreader roll 41 co-operating with a further roll. The edges open uniformly after leaving the spreader roll and due to the pressure of the rolls 33 converge from a point at the beginning of the heater 23 to the end thereof. In an example, stock 0À135 in. thick formed into an open seamed tube of ¥ in. to 3 in. diameter is moved at 16 feet per minute and heated by atomic hydrogen jets at 2¢ to 3¢ lbs. pressure with a temperature in the neighbourhood of 7000‹ F. The edges of the stock when it enters the first pair of electrodes are <3>/32 in. apart and are in contact after it passes the fourth pair of electrodes, a distance of from four to five inches. Specification 384,672 is referred to.