Black tea is roll broken after withering, there is no steaming as the enzymes need to remain active. (Withering is moisture evaporating from the leaf.)
Roll breaking cracks the surface of the leaf exposing the leaf's enzymes to oxygen initiating oxidation.
Oxidation is the process that results in the flavor profiles of Oolong & Black tea.
After FULL oxidation occurs, the leaf is then finished with forced hot air.