Paper Title
Very High Frequency Fatigue Tests (20 KHz), on the Aeronautical Steel Maraging 300

Very high frequency fatigue tests (20 KHz), were carried out on the maraging 300 steel, at room temperature and under full reversed load ratio (R=-1). The dimensions of testing specimens (hourglass shape), were determined by modal numerical simulation, using the mechanical properties of this steel: density, Young Modulus and Poisson ratio, and fitting the resonance condition required under this fatigue modality. Ultrasonic fatigue tests were performed under five loading stresses: 585, 535, 486, 438 and 389 MPa, corresponding to industrial loads. Fracture surfaces were analyzed with scanning electronic microscope, in order to obtain the origin and causes of crack initiation and propagation under this testing conditions. In addition, general conclusions were addressed concerning the ultrasonic fatigue endurance of this aeronautical steel under R=-1, together with the crack initiation and propagation behavior. Keywords - Ultrasonic fatigue, Maraging 300, Resonance, Failure Analysis, Crack Initiation Inclusion.