Abstract: A down hole motor is used in the oil prospecting industry to drive drill bits for drilling the ground at great depths. The down hole motor (1) includes a drive shaft (5) held in the motor body (3) by an axial thrust bearing (6) and by a radial bearing (7). The radial bearing (7) is a tubular member whose interior surface is coated with an anti-abrasion layer (11) formed by laser-assisted facing directly inside an alloy steel radial bearing body (10). The thickness of the facing layer is then reduced by removing material by the use of a cutting tool. This produces a radial bearing (7) that is relatively insensitive to drilling mud and confers great reliability on the down hole motor (1).

Abstract: The present invention concerns the down hole motors used in the oil prospecting industry to drive drill bits for drilling the ground at great depths. The down hole motor (1) comprises a drive shaft (5) held in the motor body (3) by an axial thrust bearing (6) and by a radial bearing (7). The radial bearing (7) is a tubular member whose interior surface is coated with an anti-abrasion layer (11) formed by laser-assisted facing directly inside an alloy steel radial bearing body (10). The thickness of the facing layer is then reduced by removing material by means of a cutting tool. This produces a radial bearing (7) that is relatively insensitive to drilling mud and confers great reliability on the down hole motor (1).

Abstract: The present invention concerns the down hole motors used in the oil prospecting industry to drive drill bits for drilling the ground at great depths. The down hole motor (1) comprises a drive shaft (5) held in the motor body (3) by an axial thrust bearing (6) and by a radial bearing (7). The radial bearing (7) is a tubular member whose interior surface is coated with an anti-abrasion layer (11) formed by laser-assisted facing directly inside an alloy steel radial bearing body (10). The thickness of the facing layer is then reduced by removing material by means of a cutting tool. This produces a radial bearing (7) that is relatively insensitive to drilling mud and confers great reliability on the down hole motor (1).

Abstract: Device for resurfacing a concave face (2) of a tubular part (1) by supplying resurfacing material and energy by a laser, comprising a laser source for generating a laser beam (9), resurfacing material delivery means (5) based on hard refractory particles and metal alloy particles, in order to deliver the resurfacing material close to a resurfacing zone (6) on the concave face (2) of the tubular part (1) to be resurfaced, laser beam delivery means (7) and directing means (8) for directing the laser beam (9) into the resurfacing zone (6). The laser source is a diode laser (4) and the laser beam delivery means (7) conduct the latter over a penetration length (L) along a penetration direction and then the directing means (8) deflect the laser beam (9) into a radial direction (II-II) away from the penetration direction, so that the laser source may lie outside the tubular part (1) and the laser beam delivery means (7) may be axially engaged completely or partly in the tubular part (1).

Abstract: A debarking knife includes a plate having at least one sharp debarking edge delimited by a leading face and a trailing face. The leading face is reinforced by an anti-abrasion hard surface coating having better anti-abrasion qualities than the substrate forming the plate. The anti-abrasion hard surface coating is preferably a mixture of grains of fused tungsten carbide bound by an Ni/Cr/B/Si alloy, the whole being brazed to the substrate using a laser beam.

Abstract: A paper pulp defibering or refining plate in accordance with the invention comprises a comminuting surface having a large number of ridges separated by grooves. The plate body is made from a first material such as stainless steel or cast iron providing the overall mechanical strength of the plate in use. The upper part of the ridges is a layer of an abrasion resistant material based on grains of tungsten carbide bound in a metal alloy whose melting and brazing characteristics are appropriate to laser resurfacing on the plate body. The ridges are resurfaced successively by scanning a laser beam and a powder spray nozzle in one or more passes.

Abstract: A paper pulp defibering or refining plate in accordance with the invention comprises a comminuting surface having a large number of ridges separated by grooves. The plate body is made from a first material such as stainless steel or cast iron providing the overall mechanical strength of the plate in use. The upper part of the ridges is a layer of an abrasion resistant material based on grains of tungsten carbide bound in a metal alloy whose melting and brazing characteristics are appropriate to laser resurfacing on the plate body. The ridges are resurfaced successively by scanning a laser beam and a powder spray nozzle in one or more passes.

Abstract: An excavating tool tooth includes a mounting area (10) and a working area (11). The working area (11) includes longitudinal bars (14-18) made of a hard material. The bars are inserted in the steel and snugly contact the tooth's cutting face. The presence of the rods made of a hard material substantially increases the tooth's service life. The bars are produced by infiltration.

Abstract: The process according to the invention involves using an infiltration technique with a binder metal 16 in a layer filled with grains of melted tungsten carbide 15, the layer being arranged between the walls of a mould 13 and a core 2, the walls of the mould being made of foundry sand bonded by resins. The invention makes it possible to reduce the cost of the infiltration process.

Abstract: The present invention relates to the manufacture of abrasion-proof plates. The abrasion-proof surface of the plate is composed of external face 5 of a layer of composite material based on spherical grains of melted tungsten carbide bonded in a soldering alloy. Grinding surface 5 has a smooth and even mould finish. The abrasion-proof layer contains a compact, regular and essentially uniform random distribution of tungsten carbide grains. Surface 5 is made by moulding: the tungsten carbide grains are inserted between the mould walls and core 2 of the part, and the soldering alloy is made to infiltrate between the powder grains, core 2 and the mould by increasing the temperature. The invention allows a significant increase in the abrasion resistance of grinding plates.

Abstract: A method and device are provided for producing refractory materials by induction, in which process a mixture of material powders and a binder in solution in water are compacted by extrusion so as to form a solid bar. The bar is introduced into a cold crucible and is caused to melt by magnetic induction. The molten material flows through a lower orifice of the crucible. The invention applies more particularly to the melting of tungsten carbide.