Ductile-Brittle Transition in Martensitic 12%Cr Steel
V. Dudko, J. Borisova, R. Kaibyshev
Belgorod State University, Pobeda 85, Belgorod 308015, Russia
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Mechanical behavior of a 12Cr-0.6Mo-2.2W-4Co-0.8Cu-VNb steel was studied by tension and the Charpy impact tests in the temperature range of 133-473 K. The yield stress and uniform elongation increase concurrently with decrease of temperature because of the work-hardening rate tends to increase with decrease of temperature. At temperatures below 213 K, the steel exhibits a poor-defined yield plateau. Impact tests demonstrate that the ductile-brittle transition occurs at 323 K. The impact toughness value comprises 250 J/cm2 at ≥373 K. The impact toughness decreases to 100 J/cm2 at room temperature. The steel becomes completely brittle at 273 K, when the absorbed energy falls to 8 J/cm2. Fracture mechanisms in 12Cr-0.6Mo-2.2W-4Co-0.8Cu-VNb steel are discussed.

DOI:10.12693/APhysPolA.134.649
PACS numbers: 81.70.Bt, 81.40.Np