Regularities of Formation of Structure, Texture and Properties under the Combined Plastic Deformation of the Low-Carbon and Ultralow-Carbon Steels for Cold Press Forming

Abstract

The current paper reports the new solutions intended to enhance the complex of mechanical properties and tendency to the press forming of the hot-rolled low-carbon and ultralow-carbon steels with subsequent cold deformation via upsetting and torsion under hydrostatic pressure (THP). Using state-of-the-art research methods, the feasibility of forming an ultra-fine-crystalline structure through the combined plastic deformation is established. The dependence of the change in mechanical properties on the structural and textural parameters as well as phase composition is established. This research is the first wherein the mechanical properties have been determined by the method of nanoindentation for the 08пс, 01ЮТ, 01ЮТ(Са), 01ЮТА steels, which were initially hot-rolled and afterwards underwent the cold deformation by the THP method. The increase in the indentation hardness by 2 times (5.5–6.0 GPa) is revealed along with the decrease of the modulus of elasticity by 1.5 times (150–190 GPa), but with the opportunity to sustain the satisfactory ductility (δ = 0.75–0.8). This provides a great suitability to the cold press forming of the steels as compared to their initial hot-rolled state.

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