Abstract: An investigation of the effects of mean and alternating stresses on short fatigue crack growth under uniaxial loading is reported. Tests under stresscontrolled conditions with different combinations of mean and alternating stresses were conducted at room temperature using a 1.99% NiCrMo steel. The fatigue process was divided into three phases: Plasticity Localization, Microstructural Short Crack (MSC) growth, and Physically Short Crack (PSC) growth. The effect of mean stress on the above three phases is stu...