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US 4,642,003 AGranted
Rotary cutting tool of cemented carbide
AssigneeMitsubishi Kinzoku Kabushiki Kaisha
InventorHironori Yoshimura
Life of this patent
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Abstract
A rotary cutting tool for processing a metal workpiece includes an elongated solid body composed of cemented carbide containing cobalt. The body has cutting edge means at its forward end and an axis of rotation therethrough. The body has a surface of which cobalt content is greater than that of the remainder of the body. Part of the surface of the body is ground to remove the cobalt-rich surface therefrom.
Claims6
A rotary cutting tool, which comprises:
- an elongated solid body, the solid body being composed of cemented carbide and containing cobalt, the elongated body including an interior portion containing cobalt and an exterior surface, the exterior surface including a relatively cobalt-rich unground surface portion and relatively cobalt-poor ground surface portions, the cobalt-rich unground surface portion having a cobalt content that is greater than the cobalt content of the cobalt-poor ground surface portions and the cobalt content of the interior portion;
- the elongated body having opposite first and second ends and including a shank portion formed at the first end, a cutting portion formed at the second end and including a relief surface and a cutting edge formed on the relief surface, and an intermediate portion interposed between the first and second ends and having at least one flute formed therein and at least one land adjacent the flute, the cobalt-poor ground surface portions of the elongated body being situated at the shank portion, land and relief surface of the elongated body, the cobalt-rich unground surface portion of the elongated body being situated at the flute of the elongated body.
A method of forming a rotary cutting tool, which comprises the steps of:
- mixing a starting powder material of cemented carbide containing cobalt together to form a powder mixture;
- compacting said powder mixture into a densified body;
- sintering the densified body in a carburizing atmosphere to form an elongated body having an exterior cobalt-rich surface;
- and
- grinding portions of the exterior surface of the elongated body to remove the cobalt-rich surface therefrom to define a relatively cobalt-rich unground surface portion and relatively cobalt-poor ground surface portions, the cobalt-rich unground surface portion having a cobalt content that is greater than the cobalt content of the cobalt-poor ground surface portions, the elongated body having opposite first and second ends and including a shank portion formed at the first end, a cutting portion formed at the second end and including a relief surface and a cutting edge formed on the relief surface, and an intermediate portion interposed between the first and second ends and having at least one flute formed therein and at least one land adjacent the flute, the cobalt-poor ground surface portions of the elongated body being situated at the shank portion, land and relief surface of the elongated body, the cobalt-rich unground surface portion of the elongated body being situated at the flute of the elongated body.
2 more elements
Dependencies are inferred from the claim text.