The Effect of Hydrostatic Pressure Environment on the Low Cycle Fatigue Properties of a Maraging Steel

To investigate the low cycle fatigue properties of an 18 percent nickel maraging steel, a high pressure fatigue testing machine including the high pressure chamber and associated hydraulic controls was designed and developed to apply simultaneously to the specimen (1) constant fluid pressure up to 100,000 psi, (2) mean uniaxial tensile or compressive stress, and (3) alternating push-pull load at a selected rate. Using this machine, notched and unnotched specimens were tested. Results indicated a definite increase in fatigue life of the material in the high pressure environment.