超超临界机组用Inconel740H合金的高温氧化性能研究
发布时间：2019-06-05 21:35
【摘要】：随着对火电机组运行参数要求的不断提升,锅炉再热器与过热器管的服役条件也越发苛刻。制造这些部件的材料需具备良好的抗高温氧化及煤烟气氧化腐蚀性能。深入研究过热器管材料Inconel740H的抗高温氧化及煤烟气氧化腐蚀的性能具有重要意义。本文对Inconel740H合金进行高温空气氧化实验,用自行设计设备进行空气-水蒸汽混合气高温氧化实验和高温煤烟气氧化腐蚀实验。使用不连续增重法称量高温实验后的试样增重并绘制增重曲线。对高温实验后试样使用扫描电镜(SEM)观察表面与截面氧化膜形貌与基体组织,通过能谱仪(EDS)分析氧化层成分。利用X射线衍射仪(XRD)分析表面氧化层相组成。研究分析了Inconel740H在不同环境下的氧化腐蚀的动力学规律及氧化腐蚀产物与氧化腐蚀温度、时间的关系。实验结果表明,Inconel740H在不同气氛环境下的氧化增重随温度提高、时间延长而增加,但具体氧化腐蚀动力学规律各异。在700℃和800℃的水蒸气氧化中的氧化动力学曲线近似遵循抛物线规律,在900℃水蒸气中的氧化动力学曲线遵循线性规律。对于空气氧化,在700℃100h内遵循线性规律,而800℃和900℃的则遵循抛物线规律。煤烟气腐蚀在700℃和900℃都近似遵循抛物线规律。水蒸气对氧化具有加速作用,相同温度下,水蒸气环境氧化增重空气环境的氧化增重。研究发现,短时间氧化后,表面氧化膜主要由Cr_2O_3构成。延长氧化时间,氧化膜物相转变成由尖晶石NiCr_2O_4以及铬钛氧化物为主。长时间氧化后生成由Al_2O_3与TiO_2组成的内氧化物。分别在700℃和800℃进行高温煤烟气腐蚀后的生成物以氧化物为主,由Cr_2O_3、SiO_2组成,另含部分NiC与S;长时间腐蚀后同样出现Al_2O_3为主的内氧化物;800℃300h煤烟气氧化腐蚀产物层出现疏松多孔现象。900℃煤烟气腐蚀后的生成物包括Cr_2O_3、Al_2O_3、NiC、SiO_2以及铬钛的混合氧化物。Inconel740H经过900℃长时间空气氧化后会发生表层氧化膜剥落现象。900℃水蒸气氧化120h后试样表层氧化膜破碎。Inconel740H在900℃长时间的空气氧化和空气-水蒸气氧化期间观察到不同程度的氧化膜剥落现象,该材料不能满足在900℃下长期服役的要求。
[Abstract]:With the continuous improvement of the operation parameters of the thermal power unit, the service conditions of the boiler reheater and the superheater tube are becoming more and more severe. The materials for making these components shall have good resistance to high temperature oxidation and oxidation of soot. It is of great significance to study the high temperature oxidation of Inconel 740H and the oxidation corrosion of soot. In this paper, the high-temperature air oxidation experiment of Inconel 740H alloy is carried out, and a self-designed equipment is used for the high-temperature oxidation experiment of air-water vapor mixed gas and the oxidation corrosion experiment of high-temperature soot. The weight gain of the sample after the high temperature experiment was weighed using a discontinuous weight gain method and the weight gain curve was plotted. The morphology of the surface and the cross-sectional oxide film was observed by scanning electron microscope (SEM) and the composition of the oxide layer was analyzed by the energy dispersive spectrometer (EDS). The surface oxidation layer was analyzed by X-ray diffractometer (XRD). The kinetics of the oxidation corrosion of Inconel 740H in different environments and the relationship between the oxidation corrosion product and the oxidation corrosion temperature and time are analyzed. The experimental results show that the oxidation weight gain of Inconel 740H in different atmosphere is increased with the temperature, and the time is prolonged, but the specific oxidation corrosion dynamics are different. The kinetics of the oxidation in water vapor oxidation at 700 鈩，
本文编号：2493838
[Abstract]:With the continuous improvement of the operation parameters of the thermal power unit, the service conditions of the boiler reheater and the superheater tube are becoming more and more severe. The materials for making these components shall have good resistance to high temperature oxidation and oxidation of soot. It is of great significance to study the high temperature oxidation of Inconel 740H and the oxidation corrosion of soot. In this paper, the high-temperature air oxidation experiment of Inconel 740H alloy is carried out, and a self-designed equipment is used for the high-temperature oxidation experiment of air-water vapor mixed gas and the oxidation corrosion experiment of high-temperature soot. The weight gain of the sample after the high temperature experiment was weighed using a discontinuous weight gain method and the weight gain curve was plotted. The morphology of the surface and the cross-sectional oxide film was observed by scanning electron microscope (SEM) and the composition of the oxide layer was analyzed by the energy dispersive spectrometer (EDS). The surface oxidation layer was analyzed by X-ray diffractometer (XRD). The kinetics of the oxidation corrosion of Inconel 740H in different environments and the relationship between the oxidation corrosion product and the oxidation corrosion temperature and time are analyzed. The experimental results show that the oxidation weight gain of Inconel 740H in different atmosphere is increased with the temperature, and the time is prolonged, but the specific oxidation corrosion dynamics are different. The kinetics of the oxidation in water vapor oxidation at 700 鈩，
本文编号：2493838
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