AbstractMethods of wide‐angle X‐ray analysis and transmission electron microscopy were performed to investigate structural and phase transformation occurring in polyamide‐6 (PA‐6) by combined solid‐phase processing including extrusion through a conical die (ED) and the following equal‐channel multiple‐angular extrusion (ECMAE). It was shown that high level of plastic and strength characteristics of extruded PA‐6 is determined by the formation of a duplex structure consisting of elongated disoriented fiber‐like entities and fragmented globular formations. Conservation of high values of plasticity of deformed PA‐6 is also controlled by the transition of the crystals of α‐form to the crystals of γ‐form with higher plasticity reserve. We have established rational technology parameters of PA‐6 processing by ED‐ECMAE processes (the deformation degree εED at ED, deformation intensity ΔΓ and the value of accumulated deformation εECMAE at ECMAE). POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers