GB467128A - Improvements relating to welding and welded joints - Google Patents

Abstract

467,128. Making expansion joints etc.; uniting by fusion. LOCKWOOD, H. C. May 5, 1936, No. 12679. [Classes 83 (ii) and 83 (iv)] In fusion welding one or more thin gauge metal parts, e.g. of less than <1>/16" for arc welding or <1>/32" for gas welding, to one or more parts of thicker gauge, the end portion of the thin part is placed in contact with the thick part and another thick part is placed on the other side of the thin part so as to define a welding zone into which the end of the thin part projects, and the projecting portion is melted and incorporated in a welding bead while maintaining an integral relationship between the thin part and the head and uniting in integral relationship the head and the thick parts. Thin sheets welded together at intervals on a ragged edge due to overheating are thus avoided. Stainless steel plates may thus be welded to one or more thick plates of stainless or carbon steel and also to each other. In arc welding a thin plate 10 to two thicker plates 11, 12, the parts are placed with their ends in alignment, the parts 11, 12 being preferably bevelled and an arc electrode 16 is first applied to the edge of the plate 11 so as to form a molten bead which melts the projecting portion of the plate 10. The arc is then applied to the edge of the plate 12 to complete the weld. A second deposit may then be applied if necessary, In welding a thin plate or a number of superposed thin plates to one thicker plate, the second thick plate of the first method is replaced by a strip 22, Fig. 3, which forms part of the finished weld. In welding a pair of thin plates 27, 28, Fig. 8, to each other, both thick plates are replaced by strips 29, 30. Instead of bevelled edges, one or other of the thick plates or strips may be arranged in stepped form as shown in Fig. 10, and the weld effected at 36<1>. In a further modification a thin plate 46, Fig. 22, may be similarly welded to an intermediate part of the thick plate. In butt welding, thin plates 55, 56, Fig. 26, strips 57, 58, 59 are placed at opposite sides of the plates and welding effected at 61. The strips 57 may be replaced by a thick plate to which the thin plates are welded. In another form, the end of the thin plate 80, Fig. 32, may be further provided on both sides with protective strips 81, 82, preferably about <1>/16" thick, or a thin-plate 87, Fig. 34, may be provided with a protective strip 88 at one side only. The welding may be effected with a metallic electrode, or a blowpipe with an extraneous metal rod, or the metal of the thin plates may project above the ends of the thicker plates to provide the necessary welding metal, heating being effected by the carbon arc &c. The end plates of the bellows 101, Fig. 36 of an expansion joint may be welded to the terminal plates 102, 103 by providing ring strips 104 at one side of each joint and welding in a manner similar to that as shown in Fig. 10.