硅含量与氧化温度对含Nb高强钢氧化行为的影响

Influence of Silicon Content and Oxidation Temperature on the Oxidation Behaviors of Nb-Containing High Strength Steel

为了更真实地反映工业生产实际工况中硅含量与氧化温度对Nb高强钢氧化行为的影响,设计了4种不同的氧化温度,采用与工业现场类似的加热制度对不同Si含量的含Nb高强钢进行氧化。采用扫描电子显微镜及能谱仪分析了氧化铁皮形貌及确定氧化铁皮各层结构。研究了硅含量及氧化温度对含Nb高强钢氧化行为的综合影响。结果表明:在相同氧气含量及氧化时间下,含Nb高强钢的氧化增重取决于氧化温度及硅含量的综合作用;当加热温度低于1 173℃(硅酸亚铁熔点)时,硅含量增加,氧化铁皮总量减少;当加热温度高于1 173℃时,硅含量增加,氧化铁皮总量增加;当硅含量较高时(1.21%,质量分数),试样的氧化增重曲线主要遵循线性规律。

Nb-containing high strength steel with different silicon content was oxidized at four different oxidation temperature by simultaneous thermal analyzer （STA） that was similar to that applied in the industrial reheating process. In addition, the morphology and structure of iron oxide scale were determined by scanning electron microscope （SEM） and energy spectrometer （EDS）. Based on the above analysis, the comprehensive effects of silicon content and oxidation temperature on the oxidation behaviors of Nb-containing high strength steel were researched. Results showed that under the same O2 content and oxidation time, the oxidation weight gain of Nb-containing high strength steel depended on the comprehensive effect of oxidation temperature and Si content. When the temperature was lower than 1 173℃（ melting point of ferrous silicate） ,the oxide scale decreased with the increase of silicon content. When the temperature was higher than 1 173℃ ,the oxide scale increased with the increasing silicon content. Furthermore, when the silicon content was higher （1.21%, mass fraction）, the weight gain versus time almost followed a linear relationship.