某涡轮泵壳体“黑线”形成过程分析及控制

Analysis and Control of “Black-line” Forming Process in Turbine Pump Housing

通过对某涡轮泵壳体涡道内腔"黑线"缺陷进行成分及组织分析,确认为氧化铝夹杂。应用铸造过程数值模拟分析技术,对氧化膜的破碎卷入过程进行了分析,得到氧化膜夹杂的形成和分布受壳体铸件的结构特点影响和决定,高压腔涡道顶部出现"黑线"是个普遍现象,不可避免。提出一种控制充型合金液温度来控制"黑线"的长度和深度的方法,达到控制"黑线"缺陷的目的。实验结果表明,通过对坩埚起吊时间控制及浇注温度的保证,壳体黑线氧化膜夹层数量及长度大幅减少,通过挠削等方式即可消除,使壳体"黑线"报废率大幅度降低。

＂Black-line＂ defects in the cortex path cavity of turbine pump housing were analyzed in microstructure and component, and the broken and involved process of oxide film was analyzed by numerical simulation technology for casting process. The results indicate that the ＂black-line＂ defects are alumina inclusions, the formation of the ＂black-line＂defects in high-press cortex path cavity is inevitable and affected by the structure of the turbine pump housing. A method to control the length and depth of ＂black-line＂ defects was presented by control the temperature of alloy melt. The amount and length of the ＂black-line＂ oxide film interlayer can be obviously decreased by controlling the lifting time of crucible and the pouring temperature. The defects can be removed by grinding, and the scrap rate of the turbine pump houses from＂black-line＂ defects is significantly reduced.