Experience in Manufacturing Titanium Alloy Forgins in VIAM Plant Conditions

Abstract

The purpose of the study was to reveal the effect of various technological aspects of manufacturing titanium alloy ВТ8 (VT8) forgings under isothermal conditions on a press with a force of 1600 kN. The starting material was OST 1 90266--86 and OST 1 90107--73 VT8 (ВТ8) alloy bars. For the forgings obtained from these rods, the score and background of the macrostructure, the type of microstructure, short-term strength, elongation, contraction and impact toughness at room temperature were determined. For forgings made from an OST 1 90266--86 bar, the effect of thermomechanical treatment on the level of properties was additionally evaluated, namely, half of the forging was recalibrated. The microstructure of the forgings which were made by thermomechanical treatment and aged was additionally investigated using scanning electron microscopy. Findings of research show a direct dependence of the quality of the final semi-finished product on the quality of the original bar. It has been established that lowering the punching temperature to the level of Tpp -- 150 °С leads to insufficient development of the structure of the deformed material over the cross section, and results in the presence of large grains from the initial bar. So, on forgings made from an OST 1 90266--86 bar, the following level of mechanical properties was achieved: σv ≥ 1000 MPa, δ ≥ 11 %, ψ ≥ 20 %, KCU ≥ 40.3 J / cm2