Changes in the Properties of Pipe Steel during Cold Deformation in Production of High Strength Profile
摘要
Abstract
The results of a study of changes in the structure and mechanical properties of pipe steel during the production of high-strength profiles are presented. A simultaneous analysis of deformation diagrams and acoustic emission signals shows differences in the deformability and fracture kinetics of the original hot-rolled sheet samples and the base metal of the formed pipe. It is established that high amount of cold deformation during pipe processing cause an increase in the dislocation density by several orders of magnitude up to 1011 cm–2, as a result of which the metal reaches its hardening limit and loses its plasticity margin, which causes a sharp (2–3 times) decrease in relative elongation.