摘要
为了估算在3%O2条件下60Si2Mn弹簧钢加热过程中外氧化层的厚度,综合考虑Si的内氧化现象以及弹簧钢表面脱碳效应的影响,构建了外氧化层厚度预测模型,并通过氧化脱碳试验、热重分析(TG/DSC+)及显微组织表征试验进行验证。氧化试验气氛条件为20%CO_(2)+3%O_(2)。试验发现,氧化层由外层的氧化铁皮、富硅层(FeO+Fe2SiO_(4))以及内氧化区组成,并随温度升高而发生内氧化区向外氧化层的转变。热重试验结果表明,在750~1 000℃范围内,氧化动力学曲线呈线性;而在1 050~1 150℃范围内,曲线则呈现抛物线型。1 000℃以下,内层的SiO_(2)和Fe_(2)SiO_(4)阻碍铁离子向外表面传输,导致氧化铁皮形成由FeO、Fe_(3)O_(4)和Fe_(2)O_(3)组成的疏松结构;温度超过1 000℃时,富硅层减少,氧化铁皮中的FeO转变为致密的Fe_(3)O_(4),从而形成致密的氧化铁皮层,抑制了氧化进程,使得动力学曲线呈现抛物线型。基于热重(TG)试验测量得到的质量变化数据、通过测量脱碳层计算脱碳减重值,考虑脱碳效应后得到氧化过程的实际增重曲线,根据Arrhenius方程计算得到750~1 000℃时弹簧钢氧化反应的激活能为119.03 kJ/mol,而1 000~1 150℃时的激活能为179.68 kJ/mol。所建模型在3%O_(2)条件下预测的弹簧钢加热过程外氧化层厚度值与试验测量值高度吻合,模型可为弹簧钢的生产和优化提供理论指导。
To estimate the thickness of the external oxide layer during the heating process of 60Si2Mn spring steel in a 3%O2 environment,a predictive model for the thickness of the external oxide layer was developed by comprehensively considering the internal oxidation phenomenon of silicon(Si)and the influence of surface decarburization effects on the spring steel.The model was validated through oxidation-decarburization experiments,thermogravimetric analysis(TG/DSC+),and microstructural characterization tests.The atmosphere conditions for the oxidation experiment were 20%CO_(2)+3%O_(2).It is found that the oxide layer consists of an outer layer of iron oxide scale,a silicon rich layer(FeO+Fez SiO_(4)),and an internal oxidation zone,and undergoes a transition from the internal oxidation zone to the external oxidation layer with increasing temperature.The thermogravimetric(TG)experiment results show that the oxidation kinetics curve is linear in the range of 750-1000℃;within the temperature range of 1050-1150℃,the curve exhibits a parabolic shape;below 1000 C,the SiO_(2) and Fe_(2)SiO_(4) in the inner layer hinder the transfer of iron ions to the outer surface,resulting in the formation of a loose structure composed of FeO,Fe_(3)O_(4),and Fe_(2)O_(3),in the oxide scale.When the temperature exceeds 1000℃,the silicon rich layer decreases,and the FeO in the iron oxide scale transforms into dense Fe_(3)O_(4),forming a dense iron oxide scale layer that inhibits the oxidation process,resulting in a parabolic kinetic curve.Based on the mass change data obtained from TG measurement,the decarburization reduction value was calculated by measuring the decarburization layer.After considering the decarburization effect,the actual weight gain curve of the oxidation process was obtained.According to the Arrhenius equation,the activation energy of the oxidation reaction of spring steel at 750-1000℃was calculated to be 119.03 kJ/mol,while the activation energy at 1000-1150℃ was 179.68 kJ/mol.The predicted thickness of the external oxide layer during the heating process of spring steel using the established model under 3%O_(2) conditions is highly consistent with the experimental measurements.This model can provide theoretical guidance for the productionand optimizationof spring steel.
作者
许文婧
陈银莉
王晓硕
XU Wenjing;CHEN Yinli;WANG Xiaoshuo(School of Advanced Engineering,University of Sience and Technology Beijing,Beijing 100083,China;Collaborative Innovation Center of Steel Technology,University of Science and Technology Beijing,Beijing 100083,China)
出处
《中国冶金》
北大核心
2025年第4期80-90,共11页
China Metallurgy
基金
国家自然科学基金面上项目(52071021)。
