Battelle Memorial Institute

Guido Walt

Jean-Pierre Budliger

Wilfried Kurz

Rolf Roggen

Benno Lux

Jean-Claude Hubert

Jean Katzarkoff

Francois Mollard

Valentin Stingelin

A tool for underwater welding comprises an open-mouthed bell with an axially extending electrode inside, part of that electrode being surrounded by a tube supplying gas under pressure from a pumping station floating on the surface. Another tube linking the bell with that pumping station supplies water under pressure to an annular chamber open toward an array of fluid-guiding blades carried by the bell. In one embodiment, the bell is rotatably mounted and carries the blades on its outer surface, being set in rotation by the oncoming flow; in another embodiment, the bell is stationary and the blades are arranged on its inner surface whereby the water swirls in a film along that surface. In either case the circulating water forms a vortex that passes along the bell periphery and around the bell mouth which is slightly spaced from the workpiece to be welded, the resulting centrifugal forces preventing the entry of surrounding water into the bell whereby a gaseous atmosphere is maintained in its interior.

Underwater welding apparatus

A metallic alloy is cast in a mold to produce a solid body by unidirectional solidification. The alloy, initially in a molten state, is cast into a mold and is completely and progressively cooled in the mold while a unidirectional thermal gradient superimposed thereon parallel to a direction determined by the configuration of the mold (predetermined direction) until a metastable equilibrium is reached in which the entire body of the melt is in a super-cooled state as a homogeneous liquid. The equilibrium is then broken to cause solidification of the alloy and the formation of dendritic crystals with their principal axes parallel to the thermal gradient substantially instantly and without noticeable advance of a solidification front across the melt.

Casting process with instantaneous unidirectional solidification

Growing community of inventors

Geneva, Switzerland

Guido Walt