Speakers
Description
Maraging steels are low carbon, high Ni steels that have an extraordinary combination of high strength, and fracture toughness at room temperature. These steels could be attractive for cryogenic structural fatigue applications with cycle requirements between hundred thousand and a million cycles, however, there is a paucity of cryogenic test data of these steels. Preliminary examinations reveal that at 77K, this alloy can operate at a cyclic stress value of 1000 MPa (r=0.1), for greater than 106 cycles. Here, we report on mechanical testing and axial fatigue life data (S-n curves) on commercially available C-250 maraging steel at cryogenic temperatures including 77K, and 4K testing. In view of application in cryogenic applications notch sensitivity issues will also be presented. Metallographic evaluations of microstructure, and fracture surfaces will be presented to correlate structure-property relationships.