四种锅炉管材料650℃/26MPa的蒸汽氧化研究  

Study on Steam Oxidation of 4 Boiler Tube Materials at 650 ℃/26 MPa

作　　者：马云海[1] 郑开云[1] 

机构地区：[1]上海发电设备成套设计研究院,上海200240

出　　处：《动力工程学报》2015年第6期509-516,共8页Journal of Chinese Society of Power Engineering

摘　　要：研究了S30432、TP347H、TP310HCbN和T91钢4种锅炉管材料在650℃/26MPa超临界水蒸气中的氧化行为,氧化1 500h后,采用增重法测量试样单位表面上的质量变化,用扫描电子显微镜(SEM)及能谱仪(EDS)分析氧化膜表面及截面形貌、微观结构和元素分布,用X射线衍射仪(XRD)进行氧化膜物相表征.结果表明:4种材料氧化情况差异显著,其抗蒸汽氧化性能很大程度上取决于合金中Cr元素的含量;4种材料都形成了双层氧化膜结构,包括内层富Cr尖晶石型氧化物及外层铁氧化物(Fe3O4或Fe3O4+Fe2O3);氧化膜中形成的孔洞会成为阳离子由材料基体向氧化膜/蒸汽界面扩散,以及氧和水分子由氧化膜/蒸汽界面向金属基体扩散的快速通道,使氧化速率加快;S30432、TP347H及TP310HCbN氧化膜的剥落机制可用屈曲模型解释,T91钢氧化膜的剥落机制可用楔入模型解释.The oxidation behavior of S30432 steel,TP347Hsteel,TP310 HCbN steel and T91 steel in water vapor atmosphere at 650 ℃/26 MPa was investigated.After oxidation for 1 500 hours,the oxidized samples were investigated gravimetrically and the oxides formed were studied by X-ray diffraction(XRD).Cross-sections through the scale were analyzed by SEM/EDS to show the thickness,morphology and microstructure and to measure the chemical composition of the oxide scales.Results show that the oxidation behavior of above materials is quite different,and their steam oxidation resistance greatly depends on the Cr content in the material.Double-layered oxides form in the S30432,TP347 H,TP310HCbN and T91 steel,which include an inner Cr-rich spinel oxide layer and an outer Fe-rich oxide layer(Fe3O4or Fe3O4+Fe2O3).The voids and cavities formed in the scale will turn into channels for outward diffusion of metallic ions and inward diffusion of oxygen and water molecules,to some extent contributed to the increase of oxidation rate.Buckling model applies to the oxide exfoliation mechanism of S30432 steel,TP347Hsteel and TP310 HCbN steel,while wedging model applies to that of the T91 steel.

关 键 词：锅炉管材料 蒸汽氧化 氧化动力学 氧化膜分析 

分 类 号：TM621.2[电气工程—电力系统及自动化]