(1. 北京科技大學(xué) 材料先進制備技術(shù)教育部重點實驗室，北京 100083；
2. 北京科技大學(xué) 現(xiàn)代交通金屬材料與加工技術(shù)北京實驗室，北京 100083)
摘 要: 提出在結(jié)晶器冷型底部設(shè)置氣隙熱阻以提高熱冷組合鑄型(HCCM)水平連鑄BFe10-1-1 管材周向組織和力學(xué)性能均勻性的方法，研究熱阻角對連鑄傳熱行為、管材周向組織和力學(xué)性能均勻性的影響。結(jié)果表明：未設(shè)置熱阻時，管材上部和下部組織均由“V”形柱狀晶組成，側(cè)部組織為與軸向呈夾角29°~36°的柱狀晶，周向的柱狀晶形貌和數(shù)量分布不均勻，其周向不同部位的抗拉強度和斷后伸長率差異較大。當熱阻角為8°~32°時，隨熱阻角的增大，管材柱狀晶組織與軸向的夾角減小，周向組織和力學(xué)性能的均勻性提高。在本實驗條件下，BFe10-1-1管材HCCM 水平連鑄結(jié)晶器冷型底部設(shè)置合理的熱阻角為32°。冷型底部設(shè)置熱阻使管材周向傳熱及凝固區(qū)周向溫度場分布更為均勻，這是管材周向組織和力學(xué)性能均勻性提高的主要原因。
關(guān)鍵字: BFe10-1-1 管材；熱冷組合鑄型；水平連鑄；熱阻；組織均勻性
（1. Key Laboratory for Advanced Materials Processing,Ministry of Education,
University of Science and Technology Beijing,Beijing 100083,China;
2. Beijing Laboratory of Metallic Materials and Processing for Modern Transportation,
University of Science and Technology Beijing,Beijing 100083,China）
Abstract:A method of setting air-gap thermal resistance at the bottom of cooling mold was proposed to improve the homogeneity of circumferential microstructure and mechanical properties of BFe10-1-1 cupronickel tube produced by heating-cooling combined mold (HCCM) horizontal continuous casting. The influences of thermal-resistance angle on the heat transfer during continuous casting,circumferential microstructure and mechanical properties of the tube were investigated. The results show that for non-thermal resistance,the tube mainly consists of “V” type columnar grains at both the upper and lower parts,and axial columnar grains whose growth direction has an angle of 29°-36° to the axial direction at the lateral part. The morphology and number of the columnar grains at circumference of the tube are inhomogeneous,which induces apparent inhomogeneity of the tensile strength and elongation to failure of the tube. For the thermal-resistance angle of 8°-32°,with increasing the thermal-resistance angle,the angle between the columnar grain and the axial direction decreases,and the homogeneity of circumferential microstructure and mechanical properties of the tube is improved. The appropriate thermal-resistance angle at the bottom of cooling mold for BFe10-1-1cupronickel tube is 32°. Setting air-gap thermal resistance at the bottom of cooling mold improves the homogeneity of both circumferential heat transfer and temperature filed in the solidified zone of the tube during HCCM horizontal continuous casting,which is mainly responsible for enhancing the homogeneity of microstructure and mechanical properties of BFe10-1-1 cupronickel tube.
Key words: BFe10-1-1 tube; heating-cooling combined mold; horizontal continuous casting; thermal resistance; microstructure homogeneity
