Effect of High-Temperature Thermomechanical Treatments on Microstructure and Mechanical Properties of a High-Nitrogen Austenitic Steel

摘要

The features of microstructure and mechanical properties of a high-nitrogen austenitic steel after high-temperature thermomechanical treatments with plastic deformation after heating to T = 1100 and 600°C are investigated. It is shown that these treatments result in plastic deformation in localized areas of the material and fragmented microstructure with low- and high-angle misorientation boundaries. Plastic deformation develops more intensively in 8-ferrite than in austenite. An additional warm deformation at T = 600°C (after deformation at T= 1100°C) contributes to more intensive fragmentation of the austenite microstructure. The structural states formed after high-temperature thermomechanical treatments provide an ≈300 MPa increase in the yield strength of steel compared to the initial values with the relative elongation ≈10%. The issues of strength and plasticity of the high-nitrogen austenitic steel after thermomechanical treatments are discussed.