COMPARISON OF DOUBLE AND SINGLE PIERCING PROCESS IN SEAMLESS STEEL TUBE MANUFACTURE

Abstract

An investigation work was made on the influence of the piercing process on the rotary forging effects, redundant shear deformations and power consumption. In this work, a study was made to compare the double and single piercing process with reference to the Mannesmann piercing mill and the cone-type piercing mill developed by the authors. If the conventional double piercing process employing the Mannesmann piercing mill is replaced by the single piercing process employing the cone-type piercing mill, the rotary forging effects and redundant shear deformations can be inhibited, and then, the materials with poor workability, such as stainless and high alloy steel can be pierced without inside bore defects. Furthermore, from the viewpoints of the piercing power and power consumption, the single piercing process employing the cone-type piercing mill is very economical. As a result, the single piercing process employing the cone-type piercing mill provides the best economical advantage with respect to both capital and running costs.