Making of ring-shaped article, e.g., valve seat for aluminum engine head, involves using plastic mandrel that is melted during thermal spraying process

• Main Authors: REATHERFORD, LARRY VAN, POPOOLA, OLUDELE OLUSEGUN
• Format: Patent
• Language: English; German
• Published: 22.02.2001
• Edition: 7
• Subjects: CHEMICAL SURFACE TREATMENT; CHEMISTRY; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATIONOR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY IONIMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING MATERIAL WITH METALLIC MATERIAL; COATING METALLIC MATERIAL; DIFFUSION TREATMENT OF METALLIC MATERIAL; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION INGENERAL; METALLURGY; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THESURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION; TECHNICAL SUBJECTS COVERED BY FORMER USPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

A ring-shaped article is made by using a plastic mandrel that is melted during a thermal spraying process. Making of ring-shaped article involves preparing a hollow polymeric mandrel (10) having an exterior surface (26) dimension not greater than the desired inner dimension of the article. The mandrel has an inner surface receiving a pressurized fluid. Molten metal particles (28) are thermally sprayed onto the exterior surface of the mandrel, with the particles applying a force and transferring heat to the exterior surface. A pressurized fluid is applied to the inner surface of the mandrel. The particles melt the exterior surface of the plastic mandrel while the pressurized fluid both cools the mandrel and applies an internal pressure opposite to the force of the particles to resist the collapse of the mandrel from the heat and force of the particles. Die Erfindung betrifft ein Verfahren zur Herstellung von Ventilsitzen durch thermisches Spritzen. Das Verfahren umfaßt die Schritte: (i) Herstellung eines hohlen Polymer-Dorns, mit einer Außenfläche, die nicht kleiner als die erwünschte Innenoberfläche des Einsatzes ist, wobei der Dorn keine Mittel zum Trennen des gespritzten Materials vom Dorn aufweist, (ii) thermisches Spritzen einzelner Teilchen aus einer oder mehreren Typen Stahl- oder Nickellegierung in Gegenwart eines gesteurten Oxidationsmediums unter Bedingungen, die es erstens ermöglichen, das Schmelzen des Dorns und dessen Infiltration in das gespritzte Material und zweitens, später polymerfreies dichtes, Metallcompositionsmaterial zu bilden (iii) nach Abkühlen, Bearbeiten und Schneiden in diskrete Ventilsitzformen, um die dann in einem Endprodukt eingesetzt werden können.