| 摘要 |
PURPOSE:To head the work satisfactorily without subjecting the same to bonderizing in a header die for production of bolts by finishing the working surface of a nib made of a sintered hard alloy to a specular surface then applying TiC coating thereon. CONSTITUTION:A nib 2 made of a WC-Co base sintered hard alloy provided with a hole for working is embedded in a steel case 1, whereby a header die 3 for production of a bolt 4 is constituted. The working surface of said nib 2 is finished to a specular surface by electric discharge machining, diamond grinding or the like. The finished surface is heat-treated for a few hours at 1,030 deg.C in the flow of gaseous H2, gaseous CH4 and TiCl4 to form a TiC film of 3-10mu thickness thereon. Otherwise, a TiN coating layer formed in succession after a TiCN coating layer is formed thereon. The slip between the work and the working surface of the die is markedly improved, and the header die does not cause seizure even after the die is used for a long time without bonderizing treatment. |
