T91钢高温水蒸汽氧化层显微组织分析

Microstructure of T91 Steel Oxide layer at High-temperature and Water Vapour Condition

为避免火电厂发电机组的安全事故,深入研究了T91钢高温水蒸气氧化行为.根据氧化动力学规律,利用扫描电镜,X-ray物相分析仪对T91钢在高温水蒸汽条件下形成的氧化层显微组织进行分析.结果表明：随着温度的升高,氧化层脆性增大,破裂剥落部位为柱状晶部位;氧化层由内至外,Cr含量逐渐降低;氧化层生长方式以650℃~700℃分界,低于650℃,氧化层最外层出现须状晶芽,高于700℃,氧化层外层出现柱状晶芽和团簇状结构,随着温度的升高,组织变大.

The oxide behaviour of T91 steel at high-temperature and water vapour is studied in order to avoid accident of electrical generator in power station. On the basis of the oxidation kenetics rule,oxide layer microstructure of T91 steel at high-temperature and water vapour condition is analyzed by SEM and X-ray analyzer, and oxidation mechanism of T91 steel is disscused. The results show that brittleness of oxide layer is increased with rising temperature and the rupturing and exfoliating region is columnar crystals. Content of Cr is descreased from inter to outer oxide layer. Growth patterns of oxide layer is divided by 650- 700 ℃, below 650 ℃, whisker embryo is appeared in outer layer, above 700 ℃, columnar embryo and cluster structure was appeared, and the organization becomes larger with rising temperature.