DRILL STRING ELEMENT HAVING IMPROVED REFILL LAYER Russian patent published in 2019 - IPC E21B17/00 E21B17/10 B23K9/04 B23K31/00 

FIELD: soil or rocks drilling.

SUBSTANCE: group of inventions relates to drill string elements having improved refill layer. Drill string element having improved refill layer is proposed. Drill string element includes at least one refill layer. Said layer includes one or more cords of filler metal, each cord having a width between 1 and 5 millimeters and being laid adjacent to each other so as to form a substantially continuous layer over the area of the element. Hardness in the body of the layer varies by less than 10 HRC over said area. Method of facing the filler metal on a metal workpiece of the drill comprises the use of a welding apparatus, includes a MIG/AG torch, a tool holder on which the torch is mounted, and a workpiece holder. Method comprises the following steps: mounting the metal workpiece, comprising a peripheral surface intended for at least partial facing, on the workpiece holder; placing the tool holder with the torch and the workpiece holder in the initial relative position, in which the torch is guided to the first position of the peripheral surface; moving the tool holder and the workpiece holder relative to each other to a final relative position, in which the torch is guided to the second position of the peripheral surface, removed in the axial direction from the first position; putting the torch into cold welding during at least partial relative movement of the tool holder and workpiece holder for applying one or more adjacent cords of filler metal to form a substantially continuous layer on at least a part of the peripheral surface from first to second position, wherein the torch is put into cold welding mode during at least a partial simultaneous movement by translational motion and rotation.

EFFECT: improved facing technology and improved characteristics of the drill string element.

22 cl, 21 dwg