Stress Controlled Cyclic Deformation of Ck 15-steel at intermediate life

Experimental investigations have been carried out to study the cyclic deformation behaviour of Ck 15-steel in the intermediate life under constant stress amplitudes, 24 kp/mm² ? σ_a ≥ 30 kp/mm², in axial pushpull fatigue. In all the cases, an initial softening process followed by a hardening process has been observed during fatigue life. The plastic strain amplitudes near fatigue life of the specimens are linearly dependent on the stress amplitudes. From the experimental results, it has been observed that both the fatigue ductility exponent and the fatigue strength exponent have a value of around 0.32. Experimental observations on Ck 22 steel are in excellent agreement with these findings.