Nippon Steel Corporation

Toho Kinzoku Co., Ltd.

Nippon Hardmetal Co., Ltd.

Sakae Katayama

Masayuki Hashimura

Toshimi Tarui

Ken-ichiro Naito

Masahiro Toda

Hiroto Imamura

Norio Onodera

Tetsuo Sawashima

Tatsuya Imai

Yasushi Ishibashi

Fine graphite uniform dispersion steel excellent in cold machinability,

A cemented carbide tool of excellent wear resistance and fracture resistance includes a substrate of cemented carbide, and a ceramic coating layer by chemical vapor deposition. The thickness of the layer is in the range of between 2 .mu.m to 20 .mu.m, and the layer has cracks of such a depth that the cracks extend perpendicularly from a surface of the layer to the substrate. The cracks are formed in a network-like pattern to minutely divide the layer. The average value of the depths of the cracks in a direction perpendicular to the surface of the layer is not less than the thickness of the layer and not more than a value equal to the coating thickness plus 5 .mu.m. The average value of widths of the cracks is not more than 2 .mu.m. The average value of intervals between the cracks is not less than 10 .mu.m and not more than 100 .mu.m.

Ceramics coated cemented-carbide tool with high-fracture resistance

A continuous-cast low-carbon resulfurized free-cutting steel which consists in weight percentage of

Continuous-cast low-carbon resulfurized free-cutting steel

Growing community of inventors

Sagamihara, Japan

Sakae Katayama