The Influence of the Drawing Process on the Mechanical Properties of TRIP Steel Wires with 0.4% C Content

In the work, the results of the research concerned with the TRIP (Transformation Induced Plasticity) steel wire drawing process in experimental and theoretical ways are shown. The wire drawing process tests on the experimental way were conducted in both laboratories as well as industrial conditions, with the use of two drawing speeds (1.6 and 6 m/s) and two drawing schemes (low and high single reductions). The mechanical properties of wires drawn with high drawing speed equal to 6 m/s showed higher values of mechanical properties for wires drawn with low single reductions than for wires drawn with high single reductions. Such a phenomenon contradicts the theory of drawing wires from steel with a ferritic-pearlitic structure and must be related to TRIP structure and the presence of retained austenite in it, which is transformed into martensite during the deformation process. In order to explain this phenomenon, the theoretical wire drawing process analysis was conducted with the use of the Drawing 2D program based on the finite element method. On the base of the simulation, a large increase in temperature was found on the surface for wires drawn with high drawing speed and low single reductions, which can cause the blocking of transformation retained austenite into martensite and thus a decrease in R(m). To confirm this thesis, further studies will include tests of the amount of retained austenite in wires obtained during experimental tests.