| Summary: | 碩士 === 高苑科技大學 === 機械與自動化工程研究所 === 104 === The quality of spheroidizing annealed steel wire affects the forming quality of screws. Various parameters affect the quality of spheroidized annealing such as spheroidized annealing temperature, prolonged heating time, furnace cooling time and flow rate of nitrogen. The effects of spheroidized annealing parameters affect the quality characteristics of wires, such as tensile strength and hardness. In this study, Taguchi method is used to obtain optimum spheroidized annealing conditions to improve the mechanical properties of two AISI 1022 low carbon steel wires, produced by Dragon Steel Corporation (DSC) and Jiangsu Yonggang Group Co., Ltd. The main quality characteristic of spheroidized annealing wires is tensile strength with a target value of 39 kgf/mm2. It is revealed experimentally that, for wire of DSC, spheroidized annealing temperature and prolonged heating time are the significant factors; however, for wire of Jiangsu Yonggang Group Co., Ltd., spheroidized annealing temperature and furnace cooling time are the significant factors to influence the mechanical properties of steel wires. For wire of DSC, the qualities of mechanical properties are obviously improved, and so the formability. While for wire of Jiangsu Yonggang Group Co., Ltd., the qualities of mechanical properties are not evidently improved, neither the formability, which may be due to the composition of titanium. These results may be used as a reference for wire-manufacturers.
Keywords: spheroidizing annealed, forming quality, Taguchi method, low carbon steel wire.
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