The martensitic chromium steels, particularly alloy 616, are used for steam-turbine blades. In general, austenitic alloys are more difficult to machine than martensitic types, which machine best in the annealed condition. Crack sensitivity makes most of the martensitic steels difficult to weld by conventional methods. All of the martensitic low-alloy steels machine satisfactorily and are readily fabricated by hot working and cold working. The martensitic secondary-hardening and chromium alloys are all hot worked by preheating and hot forging.
Austenitic alloys are more difficult to forge than the martensitic grades.