采用热冷组合铸型(HCCM)水平连铸制备横断面尺寸70 mm×10 mm(宽度×厚度)具有强轴向取向柱状晶组织的纯铜板坯,研究工艺参数对纯铜板坯微观组织、表面质量与力学性能的影响.结果表明:在铜液铸造温度1250 ℃,热型段温度1100~1150 ℃,冷却水流量600 L/h、连铸拉坯速度20~80 mm/min条件下可以制备出表面粗糙度低、具有沿拉坯方向强取向组织和优良力学性能的纯铜板坯,其抗拉强度为137~141 MPa,断后伸长率为45.1%~61.7%.随着拉坯速度的增加,HCCM水平连铸所制备纯铜板坯的组织均匀性增加,晶粒尺寸变小;热型段温度升高时板坯的柱状晶组织的晶界更加平直;而总体上力学性能受拉坯速度和热型段温度的影响较小.采用HCCM水平连铸,在热型温度为1150 ℃时制备的纯铜板坯的表面粗糙度小于0.3 μm,无需进行铣面可直接进行后续冷加工,可为发展铜板带短流程生产工艺奠定基础.%Pure copper slabs with strongly-oriented columnar crystal and 70 mm in width and 10mm in thickness were fabricated by heating-cooling combined mold(HCCM) horizontal continuous casting, and the effects of processing parameters on the microstructure, surface roughness and properties of pure copper slabs were investigated. The results show that pure copper slabs with low surface roughness value and crystal orientation along the casting direction and excellent mechanical properties can be fabricated by HCCM horizontal continuous casting under processing parameters of copper melt temperature 1250 ℃, heating mold temperature 1100-1150 ℃, cooling water flow600 L/h, and casting speed 20-80 mm/min. The tensile strength and elongation after fracture of these copper slabs are in range of from 137 to 141 MPa and from 45.1% to 61.7%, respectively. Increasing casting speed would lead to more uniform structure and finer grain, and the grain boundary of columnar crystal would be more straighter when the temperature of heating-mold rose. However in the whole casting speed and temperature of heating-mold has little influence on the tensile strength and elongation after fracture. The surface roughness value of pure copper slab fabricated by HCCM horizontal continuous casting at the temperature of heating-mold of 1150 ℃ is less than 0.3 μm, which shows that the slab could be directly used to form by rolling without scalping process and be the basis of developing new compact process method of copper strip.
展开▼
