高碳冷拔钢丝的退火工艺研究

Study on Annealing Process of Cold Drawn High Carbon Steel Wire

退火过程常用来模拟冷拔高碳钢丝的镀锌过程。利用扫描电镜、透射电镜和差示扫描量热法并结合常规力学性能检测手段研究了退火过程中冷拔钢丝的珠光体组织和力学性能的变化。结果表明:在退火温度450℃时,随着退火时间的延长,冷拔钢丝的抗拉强度先小幅度增加然后减小最终达到一个稳定值;而其伸长率与抗拉强度呈相反的趋势变化。随退火时间的延长,冷拔钢丝的扭转性能先小幅度下降然后剧烈恶化,其恶化的原因是珠光体中的片状渗碳体出现球化。

The annealing process is used to simulate galvanizing process of cold drawn high carbon steel wire. Change of perlite microstructure and mechanical properties of cold drawn steel wire in annealing process was studied by using the scanning electron microscopy, transmission electron naicroscopy and differential scanning calorimetry, and combined with conventional mechanical properties testing methods. The results show that when the annealing temperature is 450 ℃, with the extension of annealing time, the tensile strength of the cold drawn wire slightly increase firstly and then decrease, finally reaches a stable value; while its elongation and tensile strength show the opposite changing trend. With the prolonging of annealing time, the torsion performance of the cold drawn wire slightly decreases firstly and then sharply worsens, and the reason for the deterioration is the spheroidization oflamellar cementite in pearlite.