WIRE DRAWING DIE

摘要

Disclosed is a wire drawing die having excellent strength and wear resistance. The wire drawing die has, as its core, a highly hard polycrystalline diamond which is produced by converting a raw material composition comprising a non-diamond carbon material directly into a diamond under ultra-high pressure/high temperature conditions without adding any sintering aid or catalyst, and which comprises substantially only a diamond. The polycrystalline diamond has a mixed structure composed of a fine diamond crystal having the largest crystal diameter of 100 nm or less and an average crystal diameter of 50 nm or less and a sheet-like or particulate coarse diamond crystal having the smallest crystal diameter of 50 nm or greater and the largest crystal diameter of 10000 nm or less.