Abstract <p>The effect of free hydrogen released during breakdown of a lubricant due to friction on the stress state of a ball bearing ring is studied. Hydrogen penetrates into the metal and affects the mechanical properties, resulting in the formation of a weakened layer in the inner ring of the bearing. The stress–strain state of the ring with an exponentially reduced elasticity modulus is determined. The equations of elasticity theory for the bearing ring mounted with tension on a rotating shaft are solved by the finite difference method. Under the influence of hydrogen, the ring is shown to experience additional radial expansion which reduces the operational clearance in the bearing. The inner ring is considered an elastic half-space to determine the depth stresses caused by the ball. The contact stress between the ball and the half-space is obtained by means of Hertzian formulas, and the stress state in the bulk of the half-space is determined by solving the Boussinesq–Cerruti problem. To this end, the displacement vector is represented in the Papkovich–Neuber form. Analytical expressions for the stress components in dimensionless form are found in terms of the simple layer potential function. Numerical integration shows that the maximum stresses by the von Mises criterion in the bearing ring are observed at a shallow depth below the contact surface of the rolling element. It is shown that additional approach between the bearing ring and the rolling element under the influence of hydrogen-induced degradation of the material results in an increase in the contact stresses relative to their calculated values, which may lead to bearing failure.</p>