In case hardening, the surface of the steel is hardened but the hardness, maximized at the surface, grades into a softer, more ductile, core. Austenitic steels have excellent ductility at ambient and at low temperatures. Disadvantage is high cost and low strength. Available in sheet, strip, plate, bar, wire and tubing. Most widely used in general applications.
Disadvantage is the tendency to grain in coarsening.
Available in bar, plate, sheet and strip. Parts requiring combination of good general corrosion resistance with good stress corrosion resistance, sea-water applications. Available in most wrought forms. Available in plate, sheet, strip, bar, tubing, shapes and wire. High strength parts, pumps, valves and paper machinery.