A kinematics study of variable lead axisymmetric forward spiral extrusion

► Variable lead axisymmetric forward spiral extrusion (VLAFSE) accumulates more strain than its counterpart AFSE. ► Proposed kinematically velocity field of VLAFSE has been confirmed experimentally. ► VLAFSE effective strain accumulates non-linearly in radial and extrusion directions. ► The rigid body rotation inside the twist zone of AFSE has been eliminated in VLAFSE.