Abstract
The article investigates the effect of combined thermomechanical processing, including pre-heat treatment and radial-shear rolling on the microstructure evolution of CuZn23Mn7Fe4 brass. The conducted studies have shown that the most optimal pre-heat treatment for CuZn23Mn7Fe4 brass before deformation on a radial-shear rolling mill is annealing at a temperature of 500°C. As a result of subsequent deformation of workpieces with an initial diameter of 30 mm, subjected to pre-annealing at a temperature of 500°C, a gradient ultrafine structure was formed in this brass alloy on a radial-shear rolling mill up to a diameter of 18 and 12 mm. Thus, in the surface layer of the deformed rod, a structure with an average grain size of 7 μm was obtained when rolling it to a diameter of 18 mm, and 3 μm when rolling it to a diameter of 12 mm. In the central layer of the bars, a structure with a grain size of 31 μm and 17 μm was obtained when rolling the bar to a diameter of 18 mm and 12 mm, respectively.