Longitudinally welded elbows made of half-shells of aluminium acc. to ASTM B361. Weld seam preparation acc. to ANSI B16.9. Suitable for processing as weld elbows in shipbuilding, plant and apparatus engineering, especially in the field of process engineering. Their advantages are the low weight, the very good seawater resistance and the temperature range from -270°C to +80°C.