High-cycle fatigue characteristics of non-heat-treated steels developed for bolt applications

►Non-heat-treated steels were developed by combining alloying and air cooling processes. ► Steels with ferrite-pearlite (F-P) and granular bainitic ferrite microstructures. ► The tensile and high-cycle fatigue properties were evaluated. ► The F-P steels can substitute for the TM steel used in 900 MPa grade bolt applications.