New technology is available for producing seamless premium forged pipes with outstanding dimensional tolerances and excellent metallurgical properties. In this paper we describe the hot-forming process based on this technology. The manufacturing sequence involves in a first step a cross-roll piercing mill to produce a hollow bar starting from solid bar pre-material. In a second step, the hollow is hot-formed in a four-hammer forging machine on a cylindrical mandrel and reduced both in outer diameter and in wall thickness. The advantages and specific benefits of this new process vs. conventional rolling processes are presented.
展开▼
