The Residual Stress Behavior in Fatigue Process of High Tensile Strength Steels (No. 1)

Abstract

The pulsating tension test by means of a Losenhausen type fatigue machine, (where maximum tensile stress is 35kg/mm2, and minimum tensile stress is 4kg/mm2) was performed of the 50kg/mm2 high tensile strength steel. And we measured surface residual stress at N=105, 2×105, 3×105, 4×105, 5×105, 7.5×105, 106, 2×106, 3×106, breakdown, (where N means the cycles to fracture)To determine the surface residual stresses, we used parallel beam X-ray diffraction method.As our result, at the center of the specimen, the behavior of the surface residual stress relating to stress repetitions showed the resembled inclination as reported before by other authors using other fatigue machines.The relations between the surface residual stresses and the stress repetitions of other grade of high tensile strength steels (especially, the tempered high tensile strength steels) remain to be confirmed hereafter.