908,061. Broaching; drawing. SALLE STEEL CO. Oct. 20, 1958 [Oct. 22, 1957 (4)]. No. 33456/58. Classes 83 (3) and 83 (4). A method of shaving a steel bar or tube consists in drawing the bar 22 through a cutting die 14, the metal at the cutting point being at a temperature such that welding of the metal to the tool is minimized. The steel, carbide or ceramic tool has a land 16 up to 0.014 inch in length, a rake angle of 0 to 40 degrees and a clearance angle of 0 to 15 degrees. A steel bar may be fed at 180 to 600 SP1/SP/min. to raise the cut metal to a temperature of 900 to 1350‹ F. A steel wire was drawn at 110-500 SP1/SP/min. through a guide 24, a tool 14, having a 20 degrees rake angle and lubricated with a sulphurized oil, and a draw die 30. The tool and die each reduced the radius by 0.005 inch. A similar test was carried out on steel using a phosphated grease. The work may be heated to 250‹ F. or the tool heated so that lower feeds may be employed, or the temperature of the tool may be increased by rotating, oscillating or reciprocating it. Specifications 908,062, 908,063, 908,064 and 908,065 are referred to.
展开▼
