Biaxial low-cycle fatigue composed of tension/compression with a static torsion was carried out on specimens of alloy steel used for shafts in mechanical structures. The behaviour of both the uniaxial and torsional stress during low cycle fatigue is analyzed for different levels of elasticity and plasticity. Results show a relaxation of the torsion loading during cyclic fatigue that depends on the plasticity level. Elastic-plastic finite element analysis was carried out on notched geometries, where local plasticity is attained at the notch, for cyclic bending and static torsion till a stabilized cyclic behaviour was reached, using the cyclic stress strain curve, kinematic hardening model with von Mises yield criterion and associative flow rule. Results of the local stress and strain analysis on the notches with cycling where imposed plasticity is localized also show a similar relaxation of the torsional stress as experimentally observed.