研究了发生堵塞爆管事故的TP347H耐热钢管氧化膜的结构和形成机理。结果表明: TP347H耐热钢的氧化膜分为三层, 最外层主要为Fe2O3, 中间层主要是Fe3O4, 还含有少量尖晶石(FeCr2O4、NiFe2O4), 最内层由富铬层(FeCr2O4和Cr2O3)和富镍金属层组成; 最外层的Fe2O3和中间层的Fe3O4是由铁离子向外传输与氧反应形成的; 最内层的富铬层和富镍金属层的形成与铬、镍与氧的亲和力大小不同而导致的选择性氧化有关。

The oxide film structure and formation mechanism of the burst TP347H heat-resistant steel pipe were studied. The results show that the oxide film was divided into three layers of outer layer, middle layer and inner layer. The outer layer was made of Fe2O3. The middle layer was made of Fe3O4 mainly and a small amount of spinel (FeCr2O4, NiFe2O4). The inner layer contained Cr-enriched oxide layer (FeCr2O4 and Cr2O3) and Ni-enriched metal layer. The iron ions in TP347H heat-resistant steel transported outward and reacted with the oxygen to form the outer Fe2O3 layer and the middle Fe3O4 layer. However, the formation of Cr-enriched oxide layer and Ni-enriched metal layer had relationship with the selective oxidation because of the different oxygen affinities of Cr and Ni.