| 摘要 |
1472904 Welding by pressure; brazing BABCOCK & WILCOX CO 13 Nov 1974 [30 April 1974] 49142/74 Heading B3R A device for forming a brazed joint and a welded joint in close proximity to one another comprises a sleeve having at one end a surface to be brazed which carries brazing material and at the other end a surface to be welded, an explosive charge within the sleeve adjacent the surface to be welded to effect welding thereof and a less powerful charge adjacent the surface to be brazed to position that surface for brazing. In an embodiment a sleeve 10 of Inconel (Registered Trade Mark) has a portion 12 at one end provided with circumferential grooves 13, 14, 15 which are filled with brazing metal 16 by melting wire placed in the grooves by an oxyacetylene torch and using a paste flux. At the other end of the sleeve surface 17 of reduced diameter is machined with a flange 21 projecting therefrom. A paper, cardbaord &c. plug 22 closes this other end of the sleeve in which is located a charge 24 of nitroguanidine 24, a disc 25 of PETN being arranged in contact with the charge and held in position by a ring 26 of balsa wood. One end of a PETN filled cord 27 is pressed against the disc 25 and extends through the sleeve to beyond the brazing end of the sleeve and a cylinder 33 of wood, polyethylene &c. is fitted around the card 27. In operation a heat exchanger with a tube leaking at or near the tube plate is filled with a protective atmosphere, the sleeve 10 is inserted into the end of the defective tube with the surface 17 being within that part of the tube located in the tube plate and the brazing metal 16 within the free standing part of the tube. The cord 27 is detonated to expand the end 12 within the tube and to weld the surface 17 to the tube, the flange 21 being pressed into the metal of the tube. The expanded sleeve is now cleaned using acetone and a resistance heater is inserted into the tube to liquify the brazing metal 16. |
