Billets are heated and forced through dies using hydraulic presses sited over pits to capture the oily hydraulic press leakage.
The output of a hydraulic press is lower, since the movement of the cylinder is slower compared to mechanical processes.
British Dictionary definitions for hydraulic press
a press that utilizes liquid pressure to enable a small force applied to a small piston to produce a large force on a larger piston. The small piston moves through a proportionately greater distance than the larger