Gray Tool Company

Allied Corporation

Charles Hays

James R Dickson

A valve cladding method and associated system for implementation including the steps of preforming solid insert-members (22,24) of a vitreous material (having a rheological state that varys with temperature), to generally conform in shape to the cavity walls (12, 14) that are to be clad. The insert-member is fixtured (32) within the cavity to provide a generally concentric, annular space (28) of predetermined thickness and length between the insert-member and the adjacent walls to be clad, thereby defining an activation volume. This volume (28) is filled with loose metal powder (48) and vibrated to achieve tap density for a given powder blend. The activation volume is degassed, evacuated and sealed. The valve body (10') a thus loaded, is heated to a temperature at which the insert members becomes pliable, in the range from one-half to full melting temperature of the powder. Pressurization of the heated article is achieved by the use of a suitable press (50, 62) mechanical or hydraulic, with adequate configured, mated dies (52, 58). The heated valve body is placed within dies appropriate for applying a pressure-ramp-cycle to the pliable insert-members, sufficient for the insert to hydrodynamically transmit the applied pressure-pulse to the activation volume, whereby the metal powder is isodynamically compacted and metallurgically bonded to the adjacent cavity walls. After cooling in normalized fashion, the insert-member material reverts to its brittle, glass-like behavioral patterns that exist at room temperature and this reversion from pliable-to-brittle properties allows easy extraction of the insert-members.

Densification of metal powder to produce cladding of valve interiors by

The method of the present invention improves the density, strength and bonding of coatings which have previously been applied to substrates by prior art methods such as chemical deposition, electrochemical processed, thermal deposition, and mechanical coating. The method of the present invention subjects the coated substrate to a thermal mechanical process in the form of a compressive stress which is applied to the coating at a temperature greater than about 0.5 T.sub.i and less than T.sub.i where T.sub.i is the incipient melting temperature. The compressive stress is preferably applied through a pressure transfer medium and should be greater in magnitude than about 30 ksi. The dwell time under maximum compressive stress can be from about 0.1 second to about 10 seconds depending on the temperature of the coating, the substrate and the magnitude of the compressive stress.

Method for improving the density, strength and bonding of coatings

The present invention is for a flat platelet powder for deposition onto a substrate. The powder is formed by fracture of brittle sheet or ribbon. The resulting powder has a faceted outline formed by fracture. The powder of the present invention produces a dense deposit.

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Pearland, TX, United States of America

Charles Hays