Low carbon steel wires were prepared by two processes,serial drawing(SD)and reverse-direction drawing(RD).Effects of the two processes on microstructure and mechanical properties in steel wires were investigated by fi...Low carbon steel wires were prepared by two processes,serial drawing(SD)and reverse-direction drawing(RD).Effects of the two processes on microstructure and mechanical properties in steel wires were investigated by field emissio scanning electron microscopy,electron backscatter diffraction(EBSD),X-ray diffraction and transmission electron microscopy(TEM).Residual compressive stress and more low-angle grain boundaries were introduced into the steel wire by the RD.As a result,the RD wires exhibited a greater tensile strength when drawing strain s<1.18.The SD encouraged grain refinement and texture formation in the wire.The SD wires exhibited a smaller average width of the elongated ferrite grain and a higher intensity of(110)fiber texture at all drawing strains.Therefore,the SD wires showed a bit greater tensile strength and 20%greater torsion performance than the RD wires at c=2.51.TEM and EBSD analysis indicated that dislocation tangle was formed easily in RD wires,and it transformed into twist boundary.This twist boundary impeded the grain refinement in the RD wires,and there were still non-fibrous grains in the RD wires even after heavy drawing.展开更多
The paper discusses a new drawing technology, based on a synchronized movement of ram and cushion with multiple bending operations in alternating directions called ＂bi-directional deep drawing（BDD）.＂ The goal is t...The paper discusses a new drawing technology, based on a synchronized movement of ram and cushion with multiple bending operations in alternating directions called ＂bi-directional deep drawing（BDD）.＂ The goal is to avoid local thinning by strengthening the weak point using local hardening. BDD operations are realized before the conventional deep drawing process. This results in a local strain hardening at the weak point of the workpiece, which is usually located at the bottom punch radius. Two major aspects have to be given attention due to the high number of process parameters. On the one hand, for process design, it is helpful to have a tool by means of which it is possible to simultaneously create both the machine program for the servo press and the initial configuration for the process simulation. From the authors＇ point of view, this complexity can only be represented by a numerical analysis method, on the other hand. Consequently, both aspects are given attention in this paper.展开更多
基金This work is supported by the National Natural Science Foundation of China(Grant No.51371050)Special Talent Program of Jiangsu Province(2015-XCL-004)+2 种基金the Industry・University Strategic Research Fund of Jiangsu Province(BY2016076-08)The study is also partly supported by the Science and Technology Advancement Program of Jiangsu Province(Grant No.BA2017112)L.C.Zhou appreciates the support provided by Fundamental Research Funds for the Central Universities and the Scientific Research Foundation of the Graduate School of Southeast University(YBJJ1674).
文摘Low carbon steel wires were prepared by two processes,serial drawing(SD)and reverse-direction drawing(RD).Effects of the two processes on microstructure and mechanical properties in steel wires were investigated by field emissio scanning electron microscopy,electron backscatter diffraction(EBSD),X-ray diffraction and transmission electron microscopy(TEM).Residual compressive stress and more low-angle grain boundaries were introduced into the steel wire by the RD.As a result,the RD wires exhibited a greater tensile strength when drawing strain s<1.18.The SD encouraged grain refinement and texture formation in the wire.The SD wires exhibited a smaller average width of the elongated ferrite grain and a higher intensity of(110)fiber texture at all drawing strains.Therefore,the SD wires showed a bit greater tensile strength and 20%greater torsion performance than the RD wires at c=2.51.TEM and EBSD analysis indicated that dislocation tangle was formed easily in RD wires,and it transformed into twist boundary.This twist boundary impeded the grain refinement in the RD wires,and there were still non-fibrous grains in the RD wires even after heavy drawing.
基金financed by the ‘‘Arbeitsgemeinschaft industrieller Forschungsvereinigungen-Otto von Guericke e. V.’’ (AiF) as part of the program to support ‘‘Industrial Community Research and Development’’ (IGF) with funds from the ‘‘Federal Ministry for Economic Affairs and Energy’’ (BMWi) following an order by the German Federal Parliament
文摘The paper discusses a new drawing technology, based on a synchronized movement of ram and cushion with multiple bending operations in alternating directions called ＂bi-directional deep drawing（BDD）.＂ The goal is to avoid local thinning by strengthening the weak point using local hardening. BDD operations are realized before the conventional deep drawing process. This results in a local strain hardening at the weak point of the workpiece, which is usually located at the bottom punch radius. Two major aspects have to be given attention due to the high number of process parameters. On the one hand, for process design, it is helpful to have a tool by means of which it is possible to simultaneously create both the machine program for the servo press and the initial configuration for the process simulation. From the authors＇ point of view, this complexity can only be represented by a numerical analysis method, on the other hand. Consequently, both aspects are given attention in this paper.
