上引铸造无氧铜杆的气孔特征及其形成机理

Gas Hole Characteristics and Forming Mechanism of Oxygen Free Copper Rod with Up Casting

采用光学显微镜观察了上引法铸造无氧铜杆出现的气孔缺陷，结果发现：气孔以铜杆轴心为中心，均匀分布于一环形区域内。从上引铸造的凝固特点及热力学的观点分析了上述气孔的形成机理，认为气孔是由于水蒸汽Ｈ２Ｏ（ｇ）所造成，即溶解于铜液中的氢（Ｈ）和氧（Ｏ）发生水蒸汽反应：２［Ｈ］＋［Ｏ］＝Ｈ２Ｏ（ｇ）。水蒸汽与潮湿的气候及未严格干燥的炉料密切相关。

Gas hole characteristics of oxygen free copper rod with Up casting was observed by means of optical microscope(OM). It is demonstrated that gas holes equally distribute in the district of circularity around the axial center of copper rod. According to solidification characteristic of Up casting and thermodynamic theory, the forming mechanism of gas holes was analyzed. It is presented that the gas holes were caused by vapours. Hydrogen reacts with oxygen and forms water vapour H 2O (g) , that is, 2+=H 2O (g) . Water vapours are associated with humid climate and wet raw materials.