1992 Volume 78 Issue 12 Pages 1824-1830
On a boron containing 18%Ni maraging steel of high strength grade, a small amount of austenite was retained at room temperature by the unrecrystallization solution treatment (URST). Toughening due to short time URST can be realized when the microstructure after the solution treatment consists of fine martensite and a small amount of retained austenite. In the present alloy whose chemical composition is 18% Ni, 12%Co, 5%Mo, 1.5%Ti and 0.003%B, strength and toughness level achieved by the short time URST is up to 2.4GPa and 50MPa√m, respectively. The values are 1.4 times larger than those after the usual heat treatment.