Abstract: An apparatus for mixing a particulate substance, which may be in chopped or short fibre form, with a matrix metal comprises a container (11) for molten metal (10) having an aperture (12) through which a stream of the metal can fall, a feed motor (20) for feeding the particulate substance into the metal stream, and one or more downwardly inclined nozzles (23) through which jets of atomizing gas are directed on to the combined flow of metal and particulate substance. The feed motor comprising a horizontal ring (20a) which extends about and is coaxial with the molten metal stream, and which has a radial vibration imparted to it so as to form a node on the axis of the ring. The upper surface of the ring may be horizontal or may be inclined downwardly towards the axis and may have annular grooves of ratchet tooth section with the steeper part of the section facing towards the axis.

Abstract: Protection of a metal surface is carried out by applying a coating of vitreous enamel to the surface so that the enamel forms a strong bond with the metal and then spraying a coating of an atomized protective metal on the enamel. Preferably a peening operation is carried out on the surface of the sprayed metal simultaneously with or immediately after the spraying of the metal. The method is particularly advantageous in protecting steel marine structures against corrosion and, where the protective metal is cupro-nickel, fouling by marine creatures. The vitreous enamel forms an electrically insulating layer preventing galvanic action between the steel and the cupro-nickel in the presence of sea water.

Abstract: A stream of molten metal particles in a metal spraying apparatus is deflected from side to side by gas issuing from two nozzle blocks disposed at diametrically opposite sides of the stream. Gas is supplied to the two nozzle blocks (13) alternately under the control of a rotary valve (19) having a stator (18) and a cylindrical rotor (24). The rotor has two circumferentially extending grooves (26) whose cross-sectional area varies in predetermined manner and each of which serves to provide and cut off communication between an inlet port (21) for gas under pressure and an outlet port (23) which is circumferentially aligned with the inlet port and which leads to an associated one of the nozzle blocks. The areas of the inlet and outlet ports are each greater than the maximum cross-sectional area of the groove, so that the quantity of gas reaching the nozzles at each instant is determined by the instantaneous effective area of the groove (26).

Abstract: Tools and dies are made from a master pattern by making a hard chromium electroformed shell from the pattern, supporting the pattern and filling it with tool steel which applied by spray deposition of molten particles, the deposit being continuously densified by peening as it is made.

Abstract: In order to deposit metal onto a surface such as a cylindrical surface, an arc spraying method is used with a consumable electrode (16), a non-consumable electrode (18) and a jet of atomising gas (22) blown through the arc (20) in a radial direction to propel the molten metal of the consumable electrode from the acr to the cylinder wall (12). The non-consumable electrode and the atomising gas jet both rotate about the cylinder axis so that the entire surface can be covered. The supply for the consumable electrode will normally come from a reel which can be stationary such that the consumable electrode does not rotate about its own axis.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: An apparatus and method for measuring the flow stress and like characteristics of metals and other material especially at hot working temperatures. The specimen is struck simultaneously by projectiles of equal mass but unequal velocity. The velocities of the projectiles and the dimensions of the different indentations produced upon the specimen by the projectiles are terms in the formula by which the flow stress is calculated. A formula requiring only two projectiles is adequate for many materials; one requiring three projectiles may be better for materials that show work-hardening when they undergo strain at high temperature. The projectiles may be propelled pneumatically or by contact with a driven lever. Alternatively the projectiles may be in the form of masses carried as pendulums.

Abstract: A process for forming metallic articles involves generating a stream of atomized molten metal particles, directing this stream of particles at a substrate to form a deposit of the metal thereon having a desired form, and simultaneously directing at the metal as it is deposited on the substrate, a stream of rounded particles so as to consolidate the deposited metal. Apparatus for forming metallic articles includes means for generating a stream of atomized molten metal particles and means for producing a stream of rounded particles both of said means being so arranged as to cause the streams to converge on an area, and means for maintaining a substrate arranged to coincide with the area and adapted to receive thereon a deposit of the metal. The substrate may be incorporated into the metallic article product e.g.