Abstract
An addition of small amount of boron, at most several tens ppm, to 18%Ni maraging steel raised remarkably the recrystallization temperature of reversely transformed austenite up to about 1 200 K. This effect of boron addition was utilized to solution treatment of 18%Ni maraging steel under unrecrystallized austenite. It was shown that martensites transformed from unrecrystallized austenites, which contain a numerous number of dislocations, have a marked quality for their high strength and toughness. In consequence, solution treatment under unrecrystallized austenite was found to be a promising heat treatment to improve the mechanical properties of 18%Ni maraging steel.
