Bbc Brown, Boveri & Company, Limited

Gunther Schroder

Robert Singer

Olivier Mercier

Mohamed Youssef Nazmy

Gernot H Gessinger

Keith N Melton

Hans Rydstad

Roland Kunzli

Dag Richter

A fine-grained workpiece having improved mechanical properties is produced from a nickel-based superalloy by two-part forging, a blank being converted, in a first isothermal hot-forming step (curve b) above the solution-annealing temperature for the .gamma.'-phase (line a), into an intermediate form and the latter then being finally forged to give the end form in a second isothermal hot-forming step (curve c) just below the solution-annealing temperature for the .gamma.'-phase. For the first step, a degree of deformation .epsilon. of of at least 0.7 at a mean deformation rate .epsilon. of about 10.times.10.sup.-3 s.sup.-1 is required here. The second step is carried out at deformation rates .epsilon. which are one to two powers of 10 lower than those of the first step.

Process for producing a fine-grained workpiece from a nickel-based

Manufacture of a workpiece from a creep-resistant nickel superalloy which is hardened by means of an oxide dispersion, by a powder-metallurgical process in which the mechanically alloyed powder is subjected to an isothermal or quasi-isothermal hot-rolling operation, in the course of which the powder particles are converted into a flake-shaped form with a pronounced longitudinal axes, and the rolled powder is introduced into a steel container and is compressed by isostatic hot-pressing. The workpiece is afterwards subjected to an annealing treatment which is designed to develop a coarse grain size. A preferred embodiment comprises the introduction of the powder into the mold or container in an oriented manner, in order to obtain a stratified packing of the powder, and an annealing treatment which is designed to develop a coarse grain size and is performed as a zone-annealing treatment.

Process for the manufacture of a workpiece from a creep-resistant alloy

An apparatus and a process for the zone-annealing of a workpiece (1) consisting of a high-temperature material, in which the workpiece (1) is hung on a suspension device (2) actuated via a roller (3) driven by a drive motor (4) and is provided with a plate-shaped covering screen (10) having an orifice. For the dipping of the workpiece (1), there is underneath the latter a salt bath (5) which is enclosed in an insulating vessel (6) and is provided with a heating system (7) with centrally symmetrical guide plates (8) and which is closed off at the top by means of a floating insulating cover (9). The cooling of the part of the workpiece (1) which is not immersed is guaranteed by a cooling body (11) through which cooling air (14) flows and which has a central passage (12) and, at the lower end of the passage (12), a projecting edge (13) serving as a stop for the covering screen (10). The intended grain structure can be adjusted when the feed speed of the workpiece (1) is varied in portions by means of a drive motor (4) and the amount of cooling air (14). The lateral heat flux is reduced by means of jacket-like heat-insulating cladding of the workpiece (1).

Apparatus for the zone-annealing of a workpiece consisting of a

Using a heat resistant austenitic nickel based alloy, independent of the grain size in the initial material, a fine-grained finished part is produced from an unworked part which was not specially cultivated for fine grain, in a single operational step, consisting of isothermal forging.

Process for the production of a fine-grained work piece as finished part

Brittle Ni/Ti memory alloys containing copper can be transformed, from the cast condition, into semifinished product which is suitable for further processing, by a process in which a cast bar is homogenized, a little below the solidus line, and is then isothermally extruded in the temperature range from 700.degree. to 850.degree. C.

Process for manufacturing semifinished product from a memory alloy

Finished components made from Ni/Ti or Ni/Ti/Cu memory alloys can be manufactured by isothermal or quasi-isothermal ('hot die') working of sections of semifinished product, and by subsequent additional cold-working in the temperature region of the martensitic transformation by flow-turning, tapering, necking, ironing or spinning, it being possible to dispense, completely or at least to a large extent, with an additional machining operation of the metal-cutting type. Manufacture of complicated connecting elements, using the memory effect, for connecting rods, tubes, plates, etc.

Process for manufacturing a finished component from an Ni/Ti or Ni/Ti/Cu

A high-voltage, blast-actuated power switch is disclosed in which non-arcing edges are formed on a bridge conductor when the conductor is blasted. Upon blasting, the bridge conductor bends forming edges having a large radius of curvature. When the bridge conductor is blasted, an element of the bridge conductor moves in the axial direction away from the other element of the bridge conductor, thereby increasing the separation between bridge conductor elements. The axially movable bridge conductor is held in its new axial position causing the bridge conductor elements to remain separated.

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Birmenstorf, Switzerland

Gunther Schroder