材料期刊网

利用热重法研究了低碳钢在500~900℃恒温氧化动力学，利用扫描电镜和金相显微镜对氧化铁皮的表面和断面形貌进行了观察。在试验基础上建立了恒温氧化动力学模型，并推导变温条件下氧化动力学模型用于氧化铁皮厚度演变计算，并研究了氧化铁皮中三种铁的氧化物的生长方式。结果表明：数值模拟出的铁皮厚度与实测结果十分接近。这种模拟方法解决了轧制过程中，高温情况下无法直接测量氧化铁皮的厚度问题，为调整生产工艺参数、控制氧化铁皮厚度提供了参考。FeO的晶粒是以三角锥型或是金字塔型的生长方式。Fe3O4在氧化初期是以柱状晶的形式生长；而在氧化后期，Fe3O4的生长方式转变成大量的柱状晶和团簇状结构的复合组织。Fe2O3有金属须状、片层状和多边形晶粒状三种生长方式。金属须状的Fe2O3对氧化增重影响不大，但对Fe2O3层相对厚度增加。

Isothermal oxidation kinetics of low carbon steel in the range of 500-900℃ was studied by thermogravimetry. The surface and crosssectional morphologies of the oxide scale was observed using SEM and metallographic microscope. Isothermal oxidation kinetic model was given by experiment and temperaturechange kinetic model was derived. On the basis of that, the thickness of oxide scale was calculated during hot strip rolling. The growth pattern of iron oxides was studied. The results show that the simulated results are in good agreement with tested results. The simulation method is useful for adjusting rolling parameters to control scale formation during the finishing rolling process. Growth pattern of FeO crystal is triangular pyramidal. Growth pattern of Fe3O4 is columnar crystal in initial oxidation, while columnar crystal and clusters structures coexist in later oxidation. Hematite develops as whiskers, platelets and grains. Hematite whiskers do not influence the overall kinetic. However, the relative hematite thickness increases when whiskers are observed.