This specification covers requirements for MP98T rod and bar intended for use in critical wetted seawater applications, including those affecting safety of nuclear submarine systems (SUBSAFE), where high strength, fracture toughness, and seawater corrosion resistance is required at low to moderate temperatures. This alloy can display hydrogen assisted cracking under cathodic polarization of -800 and -1000 millivolts versus Ag/AgCl in seawater. However, for fastener applications this sensitivity is mitigated by requiring that threads be rolled and the fillet under the head of bolts or screws be rolled after final aging heat treatment.