铅浴淬火珠光体钢丝冷拔过程中显微组织及织构的演变

Evolution of Microstructure and Texture of Lead-Patenting Treated Pearlite Steel Wire during Cold Drawing Process

采用透射电镜、扫描电镜和电子背散射衍射系统等对铅浴淬火处理的珠光体钢丝以及经不同道次冷拔后钢丝的显微组织与织构进行了分析。结果表明：铅浴淬火处理后钢丝重新形成了无畸变的等轴晶粒,且获得了均匀的索氏体组织;钢丝在冷拔过程中,珠光体片层间距和渗碳体片层厚度随着钢丝直径减小而近似呈线性减小,渗碳体片层具有一定的塑性变形能力;在整个冷拔变形过程中,钢丝心部、中部和边部各区域的铁素体基体协调变形,平行于拉拔方向的铁素体〈110〉丝织构组分的面积分数逐渐增加,但其增加速度在某一区域内并不是不变的,而是具有交替性;随着真应变增大,〈110〉丝织构的强度不断增加,非关联最小取向差-频率曲线偏离Mackenzie分布,并在10°~20°和45°~60°取向差范围内出现峰值。

The microstructure and texture evolution of pearlitic steel wires after lead patenting （LP） treatment and after cold drawing for different passes were analyzed by means of transmission electron microscopy （TEM）, scanning electron microscopy （SEM） and electron back scattering diffraction （EBSD）systerm. The results indicate that the undistorted and equiaxial grains formed in the pearlite steel wire after LP treatment and uniform sorbite was obtained. The pearlite interlamella spacing and the thickness of cementite lamellae decreased linearly with the decrease of the diameter of the steel wire, in addition, the eementite lamellae exhibited plastic deformation ability to some extent. During the cold-drawing process, the ferritic matrix showed coordination deformation from the center to surface. Although the area fraction of （110） fiber texture of ferrite parallel to the drawing direction increased gradually with the increase of true strain, its growth rate was inhornogeneous. The strength of （110） fiber texture increased eonstinuously and the distribution of uneorrelated misorientation angle-relative frequency curves deviated from Mackenzie distribution with the increase of true strain, meanwhile, there were two peaks appeared at the range of 10°-20°and 45°-60°.