Pressure Treatment of Metals/Production of precision pipe from hard-to-deform corrosion-resistant steel and alloys

摘要

The existing production technology for corrosion-resistant steel and alloy pipe with high surface quality is long and laborious. It includes periodic rolling on a variety of mills, drawing on a mandrel, and additional finishing operations, such as grinding and electrolytic polishing, which do not always yield high geometric precision [1-3]. In the past two decades, rotational extension has been used to produce complex hollow parts in many countries, including Russia. This technology permits the manufacture of high-precision pipe of many kinds, with good mechanical characteristics and surface roughness Ra = 0.63-0.32, from high-strength alloys and corrosion-resistant steel [4, 5]. The following rotational-extension systems are most widely used: multipass extension without thinning of the billet wall (Fig. la); and one-pass and multipass extension with sine-law thinning of the wall: 5 = S_0 sin alpha, where the minimum possible a is 15 deg (Fig. 1b). Note that various combinations of these methods are possible, depending on the required geometry of the part. Special requirements are imposed on the billet precision (Table 1).