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Free keywords:
Cold rolling; Cracks; Fatigue testing; High strength steel; Laminating; Maraging steel; Plasticity; Tensile strength, Fatigue cracks; Fatigue strength; Microstructural morphology; Stress amplitudes; Stress ratio; Transformation induced plasticity, Fatigue of materials
Abstract:
Pre-cold-rolling before annealing in transformation-induced plasticity (TRIP) maraging steels changes the microstructural morphology from lamellar to granular, increasing the tensile strength. However, fatigue tests of plain specimens at ambient temperature and the stress ratio − 1 show that increased strength does not improve the fatigue strength compared to laminated TRIP-maraging steel, irrespective of stress amplitude. The disappearance of fatigue crack roughness suppresses the improvement in fatigue resistance with increasing strength. © 2019, The Minerals, Metals Materials Society and ASM International.