Manufacture of semifinished items of alloys V4Ti4Cr and V10Ti5Cr for use as a structural material in fusion applications

Abstract

Vanadium—titanium—chromium alloys are considered as structural materials with the most appropriate properties for fusion applications. However, the final ratio VTiCr in an alloy is not yet determined. On the one hand, it is offered to optimize structure on the basis of an alloy V4Ti4Cr. On the other hand, it is proposed that the optimum of total Ti and Cr content should be near 15%, and the Ti to Cr ratio should be 2:1. Melting, casting and processing by pressure of ingots of vanadium alloys V4Ti4Cr and V10Ti5Cr weighing as much as 50 kg are considered in the report. The ingots in diameters up to 130 mm were obtained by melting in vacuum-arc furnaces. Results on chemical uniformity and structure of the ingots are presented. A basic scheme of semifinished items manufacture is submitted. Rod and tube hot extrusion conditions are presented. A new technology for protection of ingot and billet surface from gases during hot processing is used to discard application of protective stainless steel and to lower temperature of processing. Sheet and tube products were made from extruded billets by cold rolling with intermediate heat treatment. The list of obtained products, including sheets 0.5–5 mm thick, rods 10–18 mm in diameter and tubes from 50 mm up to 6.0 mm in diameter is presented. The availability of large-scale ingots processing with weight above 300 kg is discussed.