摘要
研究了SPHC低碳钢分别在SO2浓度为0、100、200、500和1000 mg/m3的SO2-CO2-O2-N2混合气体中1200℃时的氧化行为,通过XRD分析氧化层的组成,使用SEM和EDX分析了氧化层的微观形貌和元素分布,采用热压缩实验和金相显微镜分析了氧化皮的除鳞难度。结果表明,SO2浓度高于200 mg/m3时,基体抗高温腐蚀性能明显降低。当SO2浓度高于500 mg/m3时,在氧化层和基体的界面处开始生成较为完整的FeS层,界面处富集的FeS降低了高温下氧化皮的粘附性,破坏高温下氧化皮的完整性,导致氧化加剧;同时降温后又附着在基体表面,提高了降温后氧化皮的去除难度。外层氧化层的Fe2O3层和Fe3O4,FeO混合层的结构在实验的SO2浓度范围内几乎保持不变。通过控制气氛中SO2含量,可以有效控制FeS在界面处的偏聚,减少低碳钢的高温腐蚀,降低后期氧化皮去除难度,提高产品的表面质量。
The corrosion behavior of a low carbon steel was investigated at 1200 ℃ in mixed SO2-CO2-O2-N2 gas atmospheres with different content of SO2.The composition of the oxide scale was analyzed by XRD.The morphology and element distribution in the oxide scale was studied by SEM and EDX.The results show that corrosion resistance of the steel reduces when the concentration of SO2 reaches 200 mg/m3.A complete FeS layer is formed at the interface of the scale and substrate while the concentration of SO2 exceeds 500 mg/m3.The FeS layer reduces the adherence of oxide scale,destroys the integrity of the oxide layer and caused severe oxidation at high temperature.In addition,the FeS layer sticks to the steel surface during cooling and affects the surface quality of later product.The structure of outer scale,which is composed of Fe2O3 layer and Fe3O4-FeO mixed layer,stays the same in the range of concentration of SO2 for the present experiments.By controlling the SO2 content in the atmosphere,the sulphur segregation at the interface can be alleviated,the high temperature corrosion of the steel can be reduced,the descaling ability is enhanced and the surface quality of finish product is improved.
出处
《材料热处理学报》
EI
CAS
CSCD
北大核心
2012年第11期98-104,共7页
Transactions of Materials and Heat Treatment
基金
国家科技部重大科技支撑项目(2006BAC02A14)
国家自然科学基金(50774073)
中国科学院知识创新工程重要方向项目(KGCS2-YW-224)
关键词
低碳钢
氧化
硫化
界面富集
除鳞性能
low carbon steel
oxidation
sulfuration
boundary segregation
descaling ability
