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将初始直径为φ7、φ5、φ3mm的QCr0.5线材进行平均应变为0.05和0.1两种不同拉拔道次的冷拉拔,得到不同应变量的试样,测试了试样的硬度和电导率,并进行了微观组织观察,研究了不同初始直径和拉拔道次对QCr0.5线材组织和性能的影响。结果表明,在同一拉拔道次下,不同初始直径线材的电导率随着应变量的增加都呈下降趋势,φ7mm线材下降最多,φ5mm线材次之,φ3mm线材下降最少。在同一初始直径下,不同拉拔道次线材的电导率随着应变量的增加都缓慢降低,硬度先快速上升,后有所下降,最后基本保持不变。平均应变为0.1的拉拔道次比平均应变为0.05时的电导率下降幅度更大,下降约37%,而硬度却始终都更高,最高硬度HV达114。微观组织观察表明,QCr0.5线材横截面组织演化的特点是:内外部组织变形不均匀,外部组织发生变形的程度比内部组织要剧烈。随着变形量的进一步加大,最后内部组织逐渐与外部组织趋于一致。
The average diameter of QCr0.5 wire with initial diameter of φ7, φ5 and φ3mm was subjected to cold drawing with average strain of 0.05 and 0.1. The specimens with different strain were obtained. The hardness and conductivity , And the microstructure was observed to study the different initial diameter and drawing pass QCr0.5 wire structure and properties. The results show that the conductivity of wire with different initial diameters decreases with the increase of strain at the same drawing pass. The wire of φ7 mm descends most, the wire of φ5 mm takes the second place, and the wire of φ3 mm drops least. Under the same initial diameter, the electrical conductivity of the wire at different drawing passes slowed down with the increase of strain, the hardness first increased rapidly and then decreased, finally remained unchanged. The average number of pull-off passes of 0.1 is larger than the average decrease of 0.05 at a strain reduction of about 37%, but the hardness is always higher with a maximum hardness of HV of 114. Microstructure observation shows that the characteristic of the cross-section evolution of QCr0.5 wire is that the deformation of the inner and outer tissues is not uniform and the deformation of the outer tissue is more severe than the inner one. As the amount of deformation further increases, the final internal organization gradually converges with the external organization.