GB815420A - Diamond cut-off wheel - Google Patents

Abstract

815,420. Moulding abrasive wheels. NORTON GRINDING WHEEL CO. Ltd. Aug. 22, 1957 [Aug. 27, 1956], No. 26506/57. Class 87(2). [Also in Group XXIII] The segments 40a, Fig. 8, of an abrasive cutoff wheel (Group XXIII) comprise an inner part 42a secured to the metal centre 70 of the wheel and an outer part inetgrally bonded to the inner part. The segments are formed initially as a ring in a mould comprising a lower plate 11, Fig. 1, outer band 10 and upper plate 12. The inner part of the ring, consisting of sintered tungsten, titanium or tantalum carbide, nickel or iron, bonded together with cobalt, is spread in a recess 25 formed between the plate 12 and a ring 14 and subjected to a pressure of 2 tons per sq. in. applied through a ring 13. The ring 14 is removed and the outer part of the ring, consisting of diamond abrasive and sintered carbide bonded together with cobalt, spread in a recess formed between the outer band 10 and the ring 13 and a pressure of 2 tons per sq. in. applied, this time, through the ring 14. Bothrings 13, 14 are then removed and a 50 ton per sq. in. pressure applied through a ring 31, Fig. 3. to bend both parts together. The bonded ring is removed from the mould and cut into the segments 42a which are placed between upper and lower graphite plates in a graphite mould consisting of segments 55, Fig. 5, which are located in bars 53, 54, in turn, positioned between segments 51, 52 in an outer ring 50. The whole is then induction heated to a temperature between 1200‹C. and 1300‹C. and subjected to a 2 tons per sq. in. pressure. After removal from the mould, the segments are secured to the metal centre 70.