Abstract
The primary objective of this study is to clarify the basic characteristics of piercing high-tensile steel plates. The secondary objective is to propose an appropriate piercing condition for obtaining high-quality holes on surfaces. An experiment on piercing a mild steel plate and two types of high-tensile steel plate is carried out using a ceramic-coated Press Working punch (PW punch ) and a ceramic-coated conventional right angle punch, with a range of clearance from 0.5 to 10%t. Here, the PW punch is used for piercing the steel plates and has been developed using cold backward extrusion technology. The main results of this study are given below: 1) If the clearance is small regardless of the shape of the punch, a high rate of shearing surface could be obtained. 2) However, in the case of piercing in a minute clearance by right angle punch, the squeeze force of steel plates to the punch flank increased sharply as the strength of the steel plates increased. 3) On the other hand, in the case of piercing in a minute clearance by the PW punch, no squeeze force after penetrating the steel plate was detected. 4) Thus, the PW punch was found to be an excellent punch for piercing high-tensile steel plates.
