Effectiveness of Application of Additional Strengthening Processing of Surface Plastic Deformation on Increase in Fatigue Life of Parts

摘要

The paper presents the results of experimental studies of the effect of additional surface plastic deformation hardening on increasing the fatigue life of parts. Hardening by the surface plastic deformation method leads to surface hardening, to the formation of details of residual stresses of compression in the surface layers, and to the favorable change of microgeometry of surfaces, which result in the increase in their fatigue and contact resistance, wear resistance, and corrosion resistance depending on the functional purpose and an external environment of details. The conducted pilot studies provided reasons for the modes of the vibroshock hardening processing of samples and determination of fatigue longevity of the samples strengthened according to five regulations. It is shown that the application of a single additional vibroshock hardening after intermediate cyclic loading (training) contributes to an increase in the fatigue life of the sample approximately by 1.2 times; double additional vibroshock hardening of samples in combination with a double intermediate cyclic loading increases fatigue durability of samples by 1.1 times; post-deformation rest of the samples has no significant effect on increase in a fatigue longevity that is caused by a stress relief or a softening in the course of aging. It has been specified that additional hardening of parts during operation will have effect under the condition that the degree of hardening of the surface layer provided by the surface plastic deformation does not exceed the maximum permissible value peculiar to a particular material.