Laboratory vacuum induction heats of 18%-Ni managing steels were cast into 25-pound ingots and forged into flat bar stock. Transverse tensile and Charpy V specimens were obtained from the forged material. One composition contained 8.4% Co, 3.2% Mb, and 0.2% Ti; five others contained 7% or 9% Co and 3.2%, 3.8%, or 5% Mb, but no titanium. Specimens were aged at various temperatures up to 1000°F, and Charpy V and tensile properties were determined at room temperature. Charpy V tests were also conducted at 30° and -20 °F. The titanium-containing composition consistently developed considerably better combinations of Charpy V toughness and yield strength than did the others. When aged at 900°F the yield strength was 190,500 psi, and the Charpy V impact energy level in the temperature range -20° to80°F exceeded 50 foot-pounds. Aging at lower temperatures resulted in greater toughness and lower yield strengths.
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