18%Ni マルエージ鋼の引張性質に及ぼす溶体化温度の影響

概要

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The effect of solution treatment temperature on the tensile properties of aged 210kg/mm^2 and 245kg/mm^2 grade 18%Ni maraging steels has been investigated. To obtain fine austenite grains, solution treatment is carried out after cold rolling. Temperatures of solution treatment are 750°, 775°, 820°, and 850℃. Time of solution treatment is 1hr. The strength of the maraging steels is increased as the solution treatment temperature is lowered. An improvement of notch toughness is observed after aging the fine grained maraging steels. However, the notch troughness of the 210kg/mm^2 grade maraging steel tends to decrease remarkably with the solution treatment at 775° or 750℃. A decrease in the notch toughness of the 245kg/mm^2 grade maraging steel is also observed in the solution treatment at 750℃. Because no undissolved precipitate remains even in the solution at 750℃ for 1hr, it is considered that the rapid decrease in notch toughness is related to the micro-segregation of solute atoms. The temperature range of the γ-to-α_M transformation is lowered when the solution temperature is decreased. The lowering of the transformation temperature is considered to be caused by the microsegregation of solute atoms and the strength increase in fine-grained austenite.
社団法人日本鉄鋼協会の論文
1976-07-01