Journals Proceedings

Abstract

The effects of machining parameters and several post-treatments on surface residual stress of round shaped specimens made of ultra-high-strength steel S960QC for fatigue testing have been investigated. Different machining parameters have been used for making the specimens and heat treatment, polishing and acid treatment have been performed to eliminate the surface residual stresses which were introduced to specimens by manufacturing process. Heat treatment proved to be the most effective method to reduce residual stresses although it did not relieve all of the high tensile residual stresses caused by machining. Turning parameters and material properties of S960QC seemed to be very essential factors and their combined effect often leads to high tensile residual stress state on the surface. Consequently, this should be taken into consideration when performing comprehensive material testing under fatigue loading, especially in high-cycle regime.