Kucharska Monika, Wiewiórowska Sylwia, Michalczyk Jacek, Gontarz Andrzej
Independent Researcher, ul. Bałtycka 9/11, 42-202 Czestochowa, Poland.
Faculty of Production Engineering and Materials Technology, Czestochowa University of Technology, 19 Armii Krajowej Av., 42-200 Czestochowa, Poland.
Materials (Basel). 2020 Dec 17;13(24):5769. doi: 10.3390/ma13245769.
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. To confirm this thesis, further studies will include tests of the amount of retained austenite in wires obtained during experimental tests.
在这项工作中，展示了以实验和理论方式对TRIP（相变诱发塑性）钢丝拉拔过程的研究结果。实验方式的钢丝拉拔过程测试在实验室和工业条件下均有进行，采用了两种拉拔速度（1.6和6米/秒）以及两种拉拔方案（低单道次减径和高单道次减径）。拉拔速度为6米/秒的高速拉拔钢丝的力学性能表明，低单道次减径拉拔的钢丝比高单道次减径拉拔的钢丝具有更高的力学性能值。这种现象与铁素体-珠光体结构钢的拉丝理论相矛盾，并且必定与TRIP组织及其内部残余奥氏体的存在有关，残余奥氏体在变形过程中会转变为马氏体。为了解释这一现象，使用基于有限元法的Drawing 2D程序对钢丝拉拔过程进行了理论分析。基于模拟发现，高拉拔速度和低单道次减径拉拔的钢丝表面温度大幅升高，这可能导致残余奥氏体向马氏体转变的受阻，从而使R值降低。为证实这一论点，进一步的研究将包括对实验测试中获得的钢丝中残余奥氏体含量的测试。
