(1. 北京科技大学 新材料技术研究院，北京 100083；
2. 现代交通金属材料与加工技术北京实验室，北京 100083；
3. 中铝材料应用研究院有限公司，北京 102209)
摘 要: 采用热冷组合铸型连铸制备d 70 mm×5mm纯铝管坯，研究连铸工艺参数对纯铝管坯表面质量、微观组织和力学性能的影响。结果表明：在铸造温度750 ℃、热型温度700~720 ℃、冷却水流量1000 L/h的条件下，可连续稳定的制备出内外表面光滑的高质量管坯。当连铸速度为20~60 mm/min时，铝管表面为强轴向取向柱状晶组织，随连铸速度增大，晶粒尺寸逐渐变小。当连铸速度为80~100 mm/min时，铝管外表面组织由柱状晶向等轴晶转变。在热型温度720 ℃、速度60 mm/min的条件下制备的纯铝管坯具有较优的表面质量和力学性能，内外表面粗糙度均小于1.6 μm，管坯抗拉强度为58.4 MPa，屈服强度为20.6 MPa，断后伸长率为28.9%，无需进行铣面可直接进行后续冷加工，有效缩短管材的制备工艺流程。
关键字: 纯铝管；热冷组合铸型；水平连铸；柱状晶组织
（1. Institute for Advanced Materials and Technology, University of Science and Technology Beijing, Beijing 100083, China;
2. Beijing Laboratory of Metallic Materials and Processing for Modern Transportation, Beijing 100083, China;
3. Chinalco Material Applications Research Institute Co., Ltd., Beijing 102209, China）
Abstract:The pure aluminum tubes of d 70 mm×5mm were fabricated by heating-cooling combined mold (HCCM) continuous casting technology. The effect of process parameters on the surface quality, microstructure and mechanical properties of tubes were analyzed. The results show that pure aluminum tubes can be continuously and stably fabricated without defects on the internal and external surfaces, when casting temperature is 750 ℃, mold heating temperature is 700-720 ℃ and cooling water flow rate is 1000 L/h. The microstructure of tubes have strong axial orientation columnar-grains on external surface when the continuous casting speed is 20-60 mm/min, and the grain size gradually decreases with the increasing of casting speed. When the continuous casting speed is 80-100 mm/min, the surface microstructure of tubes gradually transforms to equiaxed grains. When the heating-mold temperature and the casting speed are 720 ℃ and 60 mm/min, the surface roughness value of pure aluminum tubes fabricated is less than 1.6 μm, the tensile strength is 58.4 MPa, the yield strength is 20.6 MPa, and the elongation is 28.9%. This shows that tubes can be directly cold machining without milling surface, which can significantly shorten the production process.
Key words: pure aluminum tube; heating-cooling combined mold; horizontal continuous casting; columnar crystals
