Stainless Steel 13-8 MOPH 13-8 Mo is an age-hardening stainless steel with high strength and hardness along with good levels of resistance to both general corrosion and stress-corrosion cracking. PH 13-8 Mo has been used for aircraft components, nuclear reactor components, valve parts, fittings, landing gear parts, and pins.Available forms are seamless pipe, welded pipe, seamless tube, welded tube, bar, wire, sheet, plate, forgings, pipe fittings and flanges.