When the large-scale rolling deformation of a + P or P-type titanium alloy billet in one direction is too large (more than 98%), “striped grooves” are generated on the surface of the plate along the rolling direction. The experiment proves that the TC3 sheet is deformed by 50% and then reversed to roll, which can reduce the “stripe groove” to a degree that is difficult to find. When TC1 alloy sheet is rolled in one direction, the “stripe groove” can be found on the finished sheet with a thickness of 0.5 ~ 2.0mm. After 50% deformation, it is reverse-rolled to a 0.8mm thick plate, and the “stripe groove” disappears.
For highly alloyed titanium alloy plates, the commutation thickness should not be too thin. If the thickness of the sheet is too thin, it will not only increase the resistance to cold rolling deformation during commutation rolling, but also produce severe cracks. Experiments have confirmed that TC3, TC4, TC7 and other alloys are commutated and rolled below 10mm, which will cause severe cracks, dross and even scrap in the following cold rolling.
Reversing rolling of titanium alloy sheet is carried out during hot rolling. It is absolutely necessary to avoid reversing during cold rolling. Even pure titanium does not allow reversing during cold rolling. If commutation is performed during cold rolling, the average unit pressure will also be greatly increased, making rolling more difficult.