Assessment of the Hot-Cracking Susceptibility of Welded Joints of the 7CrMoVTiB10-10 Bainitic Steel Used in Heat Exchangers

Bainitic steel containing approx. 2.25% Cr and 0.6 Mo with micro-additions of V, Ti, B, designated as 7CrMoVTiB10-10 (T/P24), is one the new construction materials used in supercritical power units. The weldability defined hot-cracking susceptibility, it should be stated that hot cracking welded joints 7CrMoVTi10-10 determined by phenomena occurring high-temperature brittleness range (HTBR). In this work, HTBR established for both base material welding conditions, taking into account critical temperature-strain intensity (CST) strain speed (CSS). 122 °C wide covers temperatures from 1394 to 1516 °C. Under imposed deformation conditions (typical during welding), extends a width 293 towards lower temperatures, i.e., 1223 CSS = 0.83 1/s, CST 0.003 1/°C, Rf index 0.12, which can adopted criteria susceptibility 7CrMoVTiB 10-10 under conditions. occurs result loss cohesion thin liquid layer crystallising between growing weld crystals. Such cracks appear when or exceeded within HTBR.