(1. 北京科技大學 新材料技術研究院，北京 100083；
2. 現(xiàn)代交通金屬材料與加工技術北京實驗室，北京 100083；
3. 中鋁材料應用研究院有限公司，北京 102209)
摘 要: 采用熱冷組合鑄型連鑄制備d 70 mm×5mm純鋁管坯，研究連鑄工藝參數(shù)對純鋁管坯表面質(zhì)量、微觀組織和力學性能的影響。結果表明：在鑄造溫度750 ℃、熱型溫度700~720 ℃、冷卻水流量1000 L/h的條件下，可連續(xù)穩(wěn)定的制備出內(nèi)外表面光滑的高質(zhì)量管坯。當連鑄速度為20~60 mm/min時，鋁管表面為強軸向取向柱狀晶組織，隨連鑄速度增大，晶粒尺寸逐漸變小。當連鑄速度為80~100 mm/min時，鋁管外表面組織由柱狀晶向等軸晶轉(zhuǎn)變。在熱型溫度720 ℃、速度60 mm/min的條件下制備的純鋁管坯具有較優(yōu)的表面質(zhì)量和力學性能，內(nèi)外表面粗糙度均小于1.6 μm，管坯抗拉強度為58.4 MPa，屈服強度為20.6 MPa，斷后伸長率為28.9%，無需進行銑面可直接進行后續(xù)冷加工，有效縮短管材的制備工藝流程。
關鍵字: 純鋁管；熱冷組合鑄型；水平連鑄；柱狀晶組織
（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
