Abstract: The present invention provides a maraging steel containing: 0.10?C?0.30 mass %, 6.0?Ni?9.4 mass %, 11.0?Co?20.0 mass %, 1.0?Mo?6.0 mass %, 2.0?Cr?6.0 mass %, 0.5?Al?1.3 mass %, and Ti?0.1 mass %, with the balance being Fe and unavoidable impurities, and satisfying 1.00?A?1.08, in which A is 0.95+0.35×[C]?0.0092×[Ni]+0.011×[Co]?0.02×[Cr]?0.001×[Mo], where [C] indicates a content (mass %) of C, [Ni] indicates a content (mass %) of Ni, [Co] indicates a content (mass %) of Co, [Cr] indicates a content (mass %) of Cr, and [Mo] indicates a content (mass %) of Mo, respectively. The maraging steel has a tensile strength of 2,300 MPa or more and is also excellent in the toughness/ductility and fatigue characteristics.

Abstract: The present invention provides a maraging steel containing: 0.10?C?0.30 mass %, 6.0?Ni?9.4 mass %, 11.0?Co?20.0 mass %, 1.0?Mo?6.0 mass %, 2.0?Cr?6.0 mass %, 0.5?Al?1.3 mass %, and Ti?0.1 mass %, with the balance being Fe and unavoidable impurities, and satisfying 1.00?A?1.08, in which A is 0.95+0.35×[C]?0.0092×[Ni]+0.011×[Co]?0.02×[Cr]?0.001×[Mo], where [C] indicates a content (mass %) of C, [Ni] indicates a content (mass %) of Ni, [Co] indicates a content (mass %) of Co, [Cr] indicates a content (mass%) of Cr, and [Mo] indicates a content (mass%) of Mo, respectively, The maraging steel has a tensile strength of 2,300 MPa or more and is also excellent in the toughness/ductility and fatigue characteristics.

Abstract: A thin cast steel strip and method of making thereof with improved resistance to microcracking, where the steel strip is produced by continuous casting and contains a carbon content between about 0.010% and about 0.065% by weight, less than 5.0% by weight chromium, at least 70 ppm of total oxygen and between 20 and 70 ppm of free oxygen, and manganese to sulfur ratio greater than about 250. The carbon content in the cast strip may be below about 0.035%, less than 0.005% by weight titanium, and the average manganese to silicon ratio in the strip produced may be greater than 3.5. The carbon content may be less than 0.035%, the casting speed less than 76.68 meters per minute, and the tundish temperature of the molten metal is maintained below 1612° C. (2933.7° F.).

Abstract: A thin cast steel strip and method of making thereof with improved resistance to microcracking, where the steel strip is produced by continuous casting and contains a carbon content between about 0.010% and about 0.065% by weight, less than 5.0% by weight chromium, at least 70 ppm of total oxygen and between 20 and 70 ppm of free oxygen, and manganese to sulfur ratio greater than about 250. The carbon content in the cast strip may be below about 0.035%, less than 0.005% by weight titanium, and the average manganese to silicon ratio in the strip produced may be greater than 3.5. The carbon content may be less than 0.035%, the casting speed less than 76.68 meters per minute, and the tundish temperature of the molten metal is maintained below 1612° C. (2933.7° F.).