氮氢混合气氛下带钢表面氧化铁皮的还原

Oxide Scale Reduction of Strip Steel in Nitrogen Hydrogen Mixed Atmosphere

利用氨分解氮氢混合气氛对带钢表面氧化铁皮进行还原，研究了氧化铁皮在还原过程中的演变规律，分析了还原工艺参数对氧化铁皮表面形貌和还原减质量的影响。结果表明，还原后带钢表面产生大量裂纹和气孔；还原温度达到800℃、还原时间为7min、气流量为200L·h^-1时，即可达到理想还原效果，还原减质量达到8．34g·m^-2；还原温度700-800℃时，表面氧化铁皮层转变成脱碳的金属铁层，厚度达到200μm；温度为900℃时，表面金属铁层又转变成铁素体层；随着还原温度的升高及还原时间的增加，带钢表面氧化铁皮质量减少量增加，气流量对还原效果影响不明显。

The strip surface oxide scales reduce in nitrogen hydrogen mixed atmosphere from the decomposition of ammonia gas. The evolution of oxide scales was studied in the process of reduction, and the influence of reduction process parameters on the reduction of mass loss and oxide scale surface morphologies were analyzed. The results show that lots of crack and pore appear on the surface of steel strip after reduction. The reduction mass loss reaches 8.34 g·m^-2 at 800℃ with total of 200L·h^-1 gas flow rate in 7 min. The surface oxide scale changes into metal iron layer without carbon, the thickness is 200 μm at 700-800 ℃. The surface metal iron layer transforms into ferrite layer at 900℃. The mass reducation increases with the increase of temperature and time, and the gas flow has little effects on the reduction.