| 摘要 |
1,203,978. Welding by fusion. UNION TANK CAR CO. 24 Nov., 1967 [28 Nov., 1966], No. 53594/67. Heading B3R. In tandem are welding a horizontal joint between vertical plates, the initial pass is made at a welding speed of at least 20 inches/minute using a heat input from the electrodes of at least 100,000 joules/inch of weld and preheating the joint to about 300‹ F. The leading and trailing electrodes are respectively supplied with D.C. and A.C. During the initial pass the electrodes are directed downwardly at 30 degrees to the horizontal, the leading electrode is perpendicular to the joint and the trailing electrode is pointed forwardly towards the joint at 15 degrees to the perpendicular. During the second pass, the electrodes are raised towards the upper lip of the joint and are directed downwardly at 25-27 degrees to the horizontal. In this case the minimum welding speed is 30 inches/minute and at least 30,000 watts is supplied to the electrodes. During each pass the leading electrode is located <SP>1</SP>/ 32 inch higher than the trailing electrode. In a machine for welding a tank wall 12, leading and trailing welding heads 45, 60 are individually angularly adjustable on a supporting shaft 36 journalled in a frame 20 provided with an operator's platform and carried by motor-driven rollers running on the top edge of the tank wall 12. The supporting shaft 36 is rotatable to provide simultaneous adjustment of the welding heads 45, 60. Rollers on the frame 20 also engage the tank walls to maintain an appropriate spacing. A sighting lamp 97 providing a beam directable at the joint in advance of the electrodes 49, 69 is adjustably mounted on the shaft 36. Flux is fed from a nozzle on to a supporting belt carried by vertically adjustable rollers 85. A flame preheater is mounted on the frame 20. |
