END SEALING OF EXPERIMENTAL S.A.P. FUEL ELEMENT CANS BY PRESSURE WELDING
Results of exploratory work aimed at developing a method of end sealing S.A.P. 895 tubes (10 per cent oxide content) confirmed that neither argon-arc welding, torch brazing, nor furnace brazing can be considered suitable methods for this operation. Strength of joints produced by all three processes was insignificant, and severe internal fissures and externai blisters formed in the material. Resistance spot weiding showed some promise, but welds made under a wide range of conditions showed aluminum segregation and weld line porosity, and the extension of the method to seam welding would present problems associated with distortion of the workpiece by electrode pressure. However, by hot pressure welding under defined conditions, it was proved possible to produce end-sealed tubes with sound, helium leak-tight joints capable of withstanding internal hydraulic pressures of more than 2000 lb per sq in. at room temperature. The major disadvantage of the method is that a reduction of tube wall thickness in the region of the cap is inevitable unless the tube wall could be made thicker in the region where the weld was to be performed. On the other hand, the process is simple to operate, requires only simple equipment, and on a production scale it could be automated. (auth)
- Research Organization:
- Originating Research Org. not identified
- NSA Number:
- NSA-17-023931
- OSTI ID:
- 4686940
- Journal Information:
- Welding Metal Fabric, Vol. Vol: 30; Other Information: Orig. Receipt Date: 31-DEC-63
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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