GB747557A

GB747557A - Improvements in or relating to the production of welded tubes

Info

Publication number: GB747557A
Application number: GB3279/53A
Authority: GB
Original assignee: RHEINISCHE ROEHRENWERKE AG
Current assignee: RHEINISCHE ROEHRENWERKE AG
Priority date: 1952-02-05
Filing date: 1953-02-05
Publication date: 1956-04-11

Abstract

747,557. Making tubes. RHEINISCHE ROHRENWERKE AKT.-GES. Feb. 5, 1953 [Feb. 5, 1952], No. 3279/53. Class 83 (2). In the manufacture of tubes having longitudinal butt-welded seams, strip iron is skelped to form a slotted tube whose edges are then heated electrically and pressed together by rollers to weld the seam, the welded tube is then reduced in diameter or in both diameter and wall thickness in a reducing mill or a stretchreducing mill and is then further reduced in diameter and wall thickness in a second stretch reducing mill. Flat strip is drawn from a coil 1, Fig. 6, through a straightening device 2, flash welder 3 for butt-welding together the ends of successive coils, and burr removing device 4, by a driving device 5 from which the skelp passes in variable loops 6, 11 to a driving means 12 which conveys it through a gas furnace 21 to a rolling mill 17, for forming the slotted tube, and then to a welding-machine 18 where the edges are heated by resistance or induction heating and pressed together. The welded tube then passes through a second gas furnace 22 to a stretch reducing mill 8 after which it is cut into lengths by a flying saw 9 and passed to a tube store 10. From the latter the tubes pass through a further stretch reducing mill 13 to a tube store 15. The continuous tube may alternatively pass directly from the mill 8 to the mill 13 and be cut into lengths by a flying saw 14. In another embodiment, Fig. 4, four tube forming and welding plants 17, 18 feed the tubes, cut off into lengths by flying saws 9, to a central tube store where the ends of opposed tubes are welded together by machines 19. The tubes are drawn from the store by a driving device 12 and pass through a gas furnace 7 to the two stretch-reducing mills 8, 13. In a modification of the plant of Fig. 4, the four tube forming and welding plants are disposed at one end only of the tube store and on opposite sides of the furnace 7, Fig. 5 (not shown).