die nut
3.The punching die for nut has been treated by Ion plating of TiN The microhardness,wear resistance,failure form of TiN coating have been examed and discussed The results show that the life of TiN punching die has been increased 5 times higher than that of original punching die TiN film and a high hardness tramsitive layer can raise greatly the wear resistance and the property of impact fatigue of punching die
9.On the basis of technology analysis for the nut-box, this paper instroduced the structure of bending forming die of Ц shape stamping that was formed directly.

