Ultrasonic Fatigue Endurance of the Maraging 300 Steel

Ultrasonic fatigue tests were carried out at room temperature and under zero mean stress (R=-1), on the aeronautical steel maraging 300. Hourglass shape testing specimen dimensions were obtained by modal numerical simulation, using the mechanical proprieties of this steel: density, Young Modulus and Poisson ratio. Ultrasonic fatigue results were achieved under three loading stress: 585, 486 and 389 MPa, corresponding to high, middle and low applied stress, respectively. Fracture surfaces were analyzed with scanning electronic microscope, in order to investigate the origin and causes of crack initiation and propagation under this testing conditions. Finally, general conclusions were addressed concerning the ultrasonic fatigue endurance of this aeronautical steel, together with the crack initiation and propagation behavior.