Material Science Aspects of Titanium Tube Production. Part 2. Production of Cold-Rolled Tubes.

The article provides systematization and comparative analysis of data for structure, phase composition, physical and mechanical properties formed within deformed pipes of semifinished products in different stages of preparing cold rolled pipes from hot-rolled pipe billets of titanium alloys PT–1M, PT–7M, Ti–3Al–2.5V. The effect of the degree of cold deformation on strain hardening of specimens from alloy hot-extruded pipes of semifinished products of the test alloys is established and on the basis of this recommendations are developed for maximum acceptable degree of deformation during cold rolling of pipes made of PT–1M, PT–7M, Ti–3Al–2.5V alloys. Deformation warming of alloys during cold rolling is evaluated. It is shown that cold rolling of pipes of the alloys studied into intermediate and final pipe workpieces with the reduction recommended contributes to the pipe strain hardening. When simulating cold rolling of pipes calculation of the Q-factor is carried out, which has a value of about 1. Cold rolling with such a value of Q-factor leads to formation of a texture of an inclined tangential prism alloying alloy from PT–1M to Ti–3Al–2.5V. It is noted that intermediate and final annealing at 680°C (PT–1M alloy), 750°C (PT–7M alloy, Ti–3Al–2.5V) of cold-rolled pipe billets studied facilitates alloy loss of strength as a result of occurrence of recrystallization and to the formation of a two-component texture {0001}±φ°TD<10–10>RD and {0001}±φ°TD<11–20>RD. Features of structure formation, phase composition, and mechanical properties of pipes in relation to alloying are considered. [ABSTRACT FROM AUTHOR]