National Research Development Corporation

Sprayforming Developments Limited

Other

Ford Motor Company Limited

The Secretary of State for Defence in Her Britannic Majesty's Government

Alcan International Limited

British Technology Group Limited

The Secretary for Defence in Her Britannic Majesty's Government of the

Sprayforming Developments Limited of Innovation Center

Alfred R Singer

Allen Dennis Roche

Dennis H Sansome

Walter N Jenkins

Gordon I Davies

Richard Michael Jordan

Asgar M Alibhai

Joseph McGeough

Russell W Evans

Metallic articles having heat transfer channels and method of making

Vibrating ring motor for feeding particulate substances

Method for protecting a metal surface

Metal spraying apparatus

Method of producing tools and dies

Depositing metal onto a surface

Poppet valves are manufactured by rotating a metal spray deposition nozzle relative to a rod or tube about the longitudinal axis of the rod or tube to deposit metal at a localized region intermediate the ends of the rod or tube so as to form a flange-like accretion on the rod or tube, and subsequently cutting through the rod or tube and the accretion at the center of the localized region to form two poppet valve preforms which are then subjected to finishing treatments. Metals having differing properties of heat, wear and corrosion resistance may be coated upon one another in forming said accretion.

Poppet valve manufacture

On spray-forming metals onto a substrate from which the sprayed coating is to be detached, unwanted adhesion may occur, even to a smooth substrate. Conversely, if the coating is meant to adhere, it may accidentially delaminate, even from a roughened substrate. By vibrating the substrate, marginally adherent splats will be encouraged to detach themselves while, on the other hand, well adherent splats will not be affected.

Spray depositing of metals

Apparatus for the production of a metal article comprises means for maintaining a reservoir of molten metal with a free surface, means for rotating the free surface of the reservoir about an axis such that the molten metal is atomized and thrown outwardly away from the said surface by centrifugal action, and a substrate in the path of the atomized particles of said molten metal, whereby a solid article may be built up on the substrate by solidifying the atomized particles thereon. The molten metal may be produced by melting an electrode or otherwise. An annular solid metal article is disclosed having excellent mechanical properties. The solid metal article is produced in a single step by a spray deposition process. Molten metal is centrifugally atomized to splat and build up on a cooled mold surface disposed around the centrifuge means. Controlled relative reciprocatory movement in the direction of the rotational axis of the centrifuge is provided. By regulating this relative movement appropriately, the shape and width of the deposited article is determined. The process is carried out in an oxygen-free atmosphere. The product is a fully integrated solid, substantially free from voids, in which the original splat particle boundaries are almost undetectable, and grain growth occurs freely across the original particle boundaries.

Spray casting of articles

Metal forming process and apparatus are described. The process comprises directing a stream (4) of atomized droplets of molten metal onto a chill surface (5) such that the metal is partially solidified to form a slurry of solidified metal suspended in liquid metal. The slurry is then collected (for example, in a casting mold 7) and then cast or otherwise formed before solidification is complete. It is particularly preferred that the stream of atomized droplets is directed onto a fully solidified layer (6) of the same metal on the chill surface.

Metal forming

Aluminum is flow-coated onto ferrous strip by reducing the hot strip in hydrogen, cooling it to 650.degree.-680.degree. C. in nitrogen and spraying molten aluminum on it such that the aluminum splats flow into each other but solidify in 0.2-0.5 seconds. The aluminum is bonded to the strip through an intermetallic layer less than quarter of the total coating thickness, the aluminum having a cast structure.

Flow coating of metals

In a process for making metal strip 7, a spray 9, 10 of molten metal is directed towards a nip 13 formed by two smooth cooled rolls 6, the rolls being rotated so that the nip hot-compacts the sprayed metal to yield a strip emerging from the exit of the nip. Splats formed by droplets of the molten spray impinging on the rolls 6 before reaching the nip 13 do not stick completely to the roll surfaces but at least partially detach themselves on freezing and form a new surface on which subsequent droplets of the spray land; when the nip is reached, the partially detached frozen droplets and their overlying deposit, on both rolls, are compacted hot.

Making metal strip and slab from spray

Solid metal articles from built up splat particles

Aluminium is coated on steel strip. The steel strip is heated in hydrogen to reduce surface oxides to iron, and is then sprayed at 400.degree. C. with nitrogen-atomized molten aluminium to a depth of 150 microns. Still in nitrogen/hydrogen, at 350.degree. C., the coated strip is rolled. Under these conditions, the aluminium is subjected to very high compressive stress (compared with its yield stress) while the steel does not even reach its yield stress.

Metal-coating a metallic substrate

A two-phase material comprises a higher-melting phase dispersed in a lower-melting matrix. The material made by the method is new since, although it consists of particles of a higher-melting-point phase (e.g. iron) dispersed in a lower-melting-point matrix (e.g. aluminium), the particles being of a material soluble in the matrix at the melting-point of the matrix, no perceptible dissolution of the particles is evident in the material. Such materials may find application as friction materials, for example, in brake pads, stair edging, decking and industrial flooring. The method comprises forming a spray of molten matrix material, introducing the particles into the spray, and directing the spray onto a colder surface to solidify the matrix spray and form the multi-phase material; the method is particularly characterized in that the temperature of the spray is below the melting point of the particles, with the result that, despite the notional solubility of the particles material, no perceptible dissolution of the particles occurs. Rapid solidification is helpful in assisting to achieve this result. Thus, the particles are in contact with molten material for a duration of preferably not more than 100 ms. To ensure this, the cooling rate of the matrix in the region of the solidus is preferably at least 10.sup.3 K/s, more preferably at least 10.sup.4 K/s.

Method of making a two-phase or multi-phase metallic material

Growing community of inventors

Swansea, United Kingdom

Alfred R Singer