A structural steel which possesses both high strength and high toughness and has particular application for cryogenic uses. The steel is produced by the utilization of thermally induced phase transformation following heating in a three-phase field in iron-rich alloys of the Fe-Ni-Ti system, with a preferred composition of 12 percent nickel, 0.5 percent titanium, the remainder being iron.
An iron alloy is provided which exhibits excellent strength and toughness characteristics at cryogenic temperatures. The alloy consists essentially of about 10 to 16 percent by weight nickel, about 0.1 to 1.0 percent by weight aluminum, and 0 to about 3 percent by weight copper, with the balance being essentially iron. The iron alloy is produced by a process which includes using cold rolling at room temperature and subsequent heat treatment at temperatures ranging from 400.degree. to 650.degree. C., and possesses a fracture toughness ranging from 200 to 230 ksi .sqroot.in. and yield strengths up to 230 ksi.
A sacrificial anode for use in preventing corrosion of copper alloy parts and hydrogen absorption in titanium or titanium alloy parts of an apparatus useful for treating hot sea water, comprising a metal or metal alloy which maintains the potential of said copper alloy parts and titanium or titanium alloy parts serving as cathodes in said apparatus in the range of -0.5 to -0.65 V, relative to the potential of a saturated calomel electrode.
