GB834870A - Milling cutter for use in oil wells - Google Patents

Abstract

834,870. Abrasion tools. SERVCO MANUFACTURING CORPORATION. March 31, 1958, No. 10225/58. Class 60. An abrasive cutter for use in oil wells comprises a plurality of cutting elements 10, Fig. 3, embedded in and bonded to a matrix 9 covering the leading side face and the radially extending edge of a longitudinally extending core blade 5 secured to and projecting from a body structure 1, Fig. 1, the blade being divided transversely into a plurality of segments 8 and capable of wearing away when subjected to attrition by operation on the annular end face of a pipe or well casing so as to present succeeding segments to the pipe. A plurality of blades, each of which is divided into segments 8 by slits 7, may be secured to arms 2 adjustably-pivoted to spindles 3 disposed transversely to the axis of the body 1. The leading face, which depends on the direction of rotation, and the radially extending edge of the core have a matrix consisting of an alloy of copper, zinc or nickel-chromium-boron, in which are embedded the elements 9 each comprising cobalt-bonded grains of carbide such as tungsten, molybdenum, chromium, vanadium, zirconium, titanium, uranium tanalium or niobium, the elements being from 3/64 inch to “ inch in size. In another embodiment, the blades 12, Fig. 4, which may be of steel or steel alloy are secured to a cylindrical body 11 and some have spiral extensions 13 of reduced radial width which serve to guide the tool in the pipe. In a further embodiment, the blades 17, Fig. 5, extend radially inwards from a tubular body 16 which has a plurality of perforations filled with a matrix and cemented carbide fragments 20 to abrade any portions which may project from the wall of the pipe. In operation, as the blades wear and the pipe 14, Fig. 4, moves in the direction D relative to the tool, the slits, which may be wholly or partly filled with matrix, permit the worn portions of the segments to fall away. A window may be cut in the side of a pipe or well casing by using the embodiment shown in Fig. 4, without the spirals, in co-operation with a whipstock.