Free-machining steels exhibit good machinability and can be worked at very high speeds. Chips are short and amenable to ease of transport away from the machining zone. These characteristics render free-machining steels eminently suitable for processing in unmanned CNC-machines.
Cold-drawn round bars of free-machining steel have good tolerances and straightness. However, cold drawing does not eliminate surface defects even if such are shallower than on the hot-rolled starting material. For this reason, a drawn surface should be improved by machining and/or grinding if parts are to be surface treated.