S31042奥氏体耐热钢高温蒸汽氧化行为

Steam Oxidation Behavior of Austenitic Heat Resistant Steel S31042 at High Temperature

利用蒸汽氧化试验平台,模拟锅炉运行工况基本相似的高温蒸汽环境,对S31042奥氏体耐热钢进行了650和700℃蒸汽氧化试验。分析了氧化层的形貌、相组成和成分分布,结果表明,随着氧化时间的增长,氧化层厚度明显增加,分层现象明显,可分为内、外两层,外层为疏松多孔结构的富铁氧化物,内层为富铬氧化物;CrO2(OH)2的挥发导致了外层富铁氧化物的形成,(Fe/Cr)3O4内层的形成能够有效减缓蒸汽氧化进程,进入稳态氧化阶段后氧化层厚度将基本保持不变。

Through operating the high temperature steam oxidation equipment under almost the same steam conditions as those in actual boilers,the steam oxidation experiment for S31042 austenite heat-resisting steel in water vapor at 650 ℃ and 700 ℃ was carried out.Morphology of oxidation layer,phases and distribution of chemical compositions were analyzed.The results indicated that the thickness of oxidation layer was increased with increasing test time.The oxidation scale consists of two kinds of layers.The outer layer is rich in Fe oxide with a loose and porous structure,and the inner layer is of Cr oxide enrichment.Fe oxide can be formed with the evaporation of CrO2（OH）2.The growth rate of steam layer can be decreased with the formation of inner（Fe/Cr）3O4 layer,and the thickness of the oxides would be kept at the steady oxidation stage.