轧制压下量对连挤连轧铜排组织和性能的影响

Effects of Rolling Reduction on Microstructure and Properties of Copper Strips during Continuous Extrusion and Rolling

目的连挤连轧是一种带材生产新技术,它结合连续挤压与热轧工艺的特点,研究轧制压下量对连挤连轧铜排组织、性能的影响。方法利用光学显微镜、万能材料实验机、布氏硬度仪对铜排连挤连轧的组织、性能进行试验研究。结果经连续挤压的铜排为等轴再结晶组织,平均晶粒尺寸为60μm左右,抗拉强度为220 MPa,延伸率为66%,沿铜排宽度方向的硬度分布不均匀。连挤连轧后的铜排晶粒沿轧制方向被拉长成扁平状,随着轧制压下量的增加,相邻晶界间距减小,最终形成纤维组织,沿铜排宽度方向的硬度分布较连续挤压排坯均匀。当压下量由2 mm增加到8mm时,铜排的抗拉强度由250 MPa增加到400 MPa,延伸率由48%降低到13%,硬度由72HB左右增加到119HB。结论得到了轧制压下量对连挤连轧铜排组织和性能的影响规律。

The aim of this study was to investigate effects of rolling reduction on microstructure and properties of copper strips during continuous extrusion and rolling which was a new strip production technology combining the features of continuous extrusion and hot rolling. The microstructure and properties of copper strip during continuous extrusion and rolling were investigated by using optical microscopy,universal testing machine and Brinell hardness measurement. The results indicated that recrystallized grains were obtained by continuous extrusion,the average grain size,the tensile strength,and elongation were about 60 μm,220 MPa and 66% respectively,and the hardness distribution along the width of the copper strip was not uniform. The grains were elongated during continuous extrusion and rolling. With the rolling reduction increased,the adjacent grain boundaries spacing gradually decreased and the microstructures of copper strip gradually formed fibrous tissues,and hardness distribution became more uniform along the width direction of copper strip. The tensile strength increased from 250 MPa to 400 MPa,the elongation decreased from 48% to 13% and the hardness increased from72 HB to 119 HB when the rolling reduction increased from 2 mm to 8 mm. The influence pattern of rolling reduction on mi-crostructure and properties of copper strips during continuous extrusion and rolling was obtained.