from the conferences organized by TANGER Ltd. provisional website
Ferromanganese TWIP steels with the manganese content of 17-20 % are fully austenitic and non-magnetic, without phase transformation. Due to the application of the twinning mechanism the TWIP steels can satisfy numerous technical requirements for production of the new generation of cars. Basic experimental results of TWIP steels exhibit high ultimate tensile strength from 600 to 1100 MPa, as well as extreme values of ductility in the range from 60 to 90 %. Castings from the Fe-Mn-C alloys were prepared by method of plasma and vacuum melting. They were gradually hot rolled by three consecutive rolling sequences (first to the height of 18 mm, then to 11 mm, and finally to 3 mm), the samples were then cold rolled metal with reduction of 15 %, or 30 % to the final heights of 2.2 mm or 2.7 mm. After the second rolling the samples with dimensions of 10x15x20 mm were prepared for stress-relaxation testing on the GLEEBLE 3800. In intermediate phases the samples were taken for metallographic analysis. Dimensions of the samples did not allow execution of tensile tests that is why only the hardness was measured. The main task was to keep the samples in plastometer GLEEBLE under stress in jaws after deformation e = 0.5, followed by subsequent analysis of the recovery curves and determination of times t for selected portions of the healed structure X with display of the Avrami curves.Keywords: Fe-Mn TWIP steel, laboratory rolling, stress-relaxation method, Avrami equation
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