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采用无余量整体熔模铸造技术,成功制备出了用于某大型运载火箭发动机上的涡壳体精铸件,为了全面分析工艺的可行性,试验研究了不同截面的显微组织。结果表明:涡壳体整体上由等轴晶组成,不同截面组织均呈现枝晶特征,试验测定了二次枝晶间距,并预测了截面冷却速率与枝晶间距的关系。在较高倍数下,进、出口法兰截面组织,发现有较多的针状δ相存在,枝晶间处的γ“相尺寸较大,数量较多,枝晶干处的γ”相尺寸较小,数量较少;涡形流道截面的针状δ相很少,枝晶干及枝晶间的γ“相尺寸均较小,数量无明显差别。这些其实质与各截面的冷却速率有关。
In this paper, the casting of volute shell on a large rocket engine was successfully prepared by using the whole casting without any margin. In order to comprehensively analyze the feasibility of the process, the microstructures of different sections were experimentally studied. The results show that the volute shell is composed of equiaxed grains as a whole, and the dendrites are characterized by different cross-sections. The secondary dendrite spacing is measured and the relationship between the cooling rate and the dendrite spacing is predicted. At higher multiples, the cross-section of the inlet and outlet flanges was found, and more acicular δ phases were found. The γ ”phase size was larger and the number was larger at the interdendrites. The γ The phase size is small and the number is small; the acicular δ phase is small in the cross section of the spiral flow channel, and the γ "phase size between the dendrite stem and the dendrite is small with no significant difference in number. Of the cooling rate.