Abstract: In the present paper, a series of experiments were performed on the plastic deformation of a thin walled tubular specimen of 1Cr18Ni9Ti S.S. along trilinear, circular and elliptical strain paths under combined loads of axial force and torque. The effects of intrinsic geometry of loading path on the magnitude and the direction of stress vector were investigated in plastic strain vectoral space. Experimental results show that the delay,the instantaneous softening and the recovery of hardening of stress respo...