クロム, ニオブを含むマレージング鋼の研究

抄録

Fe-Ni-Cr maraging type steels with two different kinds of matrices were studied on their micro-substructures and aging behaviors.
1) A kind of dissimilarity was observed in the micro-substructures of martensites annealed at different levels of temperatures.
2) Increase of the annealing temperatures generally resulted in a retardation of the aging process and in higher peak hardness values which appeared to be associated with niobium.
3) Steels with higher chromium matrix had a tendency of retarding the aging process, which was observed in many features. Particularly when directly quenched to a subzero temperature, they showed peculiar subcell structures and some higher strength values.
4) In the case of higher nickel matrix the reverted austenite precipitated in a continuous manner by forming Widmanstatten figure, whereas in the higher chromium matrix rather massive austenite appeared preferentially nucleating on the sub-boundaries regardless of other precipitating substances.