Abstract: A wire drawing die 1 includes a non-diamond material, is provided with a die hole 1h, and has a reduction 1c and a bearing 1d that is positioned downstream of the reduction 1c. A reduction angle ? which is an opening angle of the die hole 1h at the reduction 1c is less than or equal to 17°, and a surface roughness Ra of the die hole 1h within ±20 ?m from a specific position inside the bearing 1d in a circumferential direction of the die hole 1h that is perpendicular to a wire drawing direction is less than or equal to 0.025 ?m.

Abstract: A wire drawing die 1 includes a non-diamond material, is provided with a die hole 1h, and has a reduction 1c and a bearing 1d that is positioned downstream of the reduction 1c. A reduction angle ? which is an opening angle of the die hole 1h at the reduction 1c is less than or equal to 17°, and a surface roughness Ra of the die hole 1h within ±20 ?m from a specific position inside the bearing 1d in a circumferential direction of the die hole 1h that is perpendicular to a wire drawing direction is less than or equal to 0.025 ?m.

Abstract: A single-crystal diamond cutting tool is provided with a flank and a rake face, a cutting edge being provided at a boundary between the flank and the rake face, an inclined surface being provided at a location distant from the cutting edge, the inclined surface being contiguous to the rake face and inclined at 0.05 degrees or more and 80 degrees or less with respect to the rake face, the rake face having a roughness Ra of 1 µm or less, the cutting edge being provided with a chamfered surface or round honing having a width of 1 µm or less, the cutting edge having projections and depressions having a width of 100 nm or less and smaller than that of the chamfered surface or round honing.

Abstract: A wear-resistant tool includes composite polycrystalline diamond as a core, the composite polycrystalline diamond being composed of polycrystalline diamond in which particulate diamond is directly bonded and non diamond carbon. The polycrystalline diamond in the composite polycrystalline diamond is three-dimensionally continuous in composite polycrystal and primary particles have an average particle size from 10 to 500 nm.

Abstract: A diamond die includes a diamond provided with a hole for drawing a wire material, the diamond being a CVD single-crystal diamond, an axis of the hole being inclined relative to a normal direction of a crystal plane of the diamond.

Abstract: A wear-resistant tool includes composite polycrystalline diamond as a core, the composite polycrystalline diamond being composed of polycrystalline diamond in which particulate diamond is directly bonded and non diamond carbon. The polycrystalline diamond in the composite polycrystalline diamond is three-dimensionally continuous in composite polycrystal and primary particles have an average particle size from 10 to 500 nm.

Abstract: A diamond die includes a diamond provided with a hole for drawing a wire material, the diamond being a CVD single-crystal diamond, an axis of the hole being inclined relative to a normal direction of a crystal plane of the diamond.

Abstract: One object of the present invention is to provide a wire drawing die excellent in strength and wear resistance. The wire drawing die has a core formed using highly hard diamond polycrystalline body made substantially only of diamond and produced by directly converting a raw material composition including a non-diamond type carbon material into diamond and sintering the diamond at an ultra high pressure and an ultra high temperature without adding a sintering aid or a catalyst, the polycrystalline body having a mixed construction including fine-grained diamond crystals with a maximum grain size of less than or equal to 100 nm and an average grain size of less than or equal to 50 nm and plate-like or particulate coarse-grained diamond crystals with a minimum grain size of greater than or equal to 50 nm and a maximum grain size of less than or equal to 10000 nm.

Abstract: One object of the present invention is to provide a wire drawing die excellent in strength and wear resistance. The wire drawing die has a core formed using highly hard diamond polycrystalline body made substantially only of diamond and produced by directly converting a raw material composition including a non-diamond type carbon material into diamond and sintering the diamond at an ultra high pressure and an ultra high temperature without adding a sintering aid or a catalyst, the polycrystalline body having a mixed construction including fine-grained diamond crystals with a maximum grain size of less than or equal to 100 nm and an average grain size of less than or equal to 50 nm and plate-like or particulate coarse-grained diamond crystals with a minimum grain size of greater than or equal to 50 nm and a maximum grain size of less than or equal to 10000 nm.