38 CrMoAl钢真空电磁感应快速渗氮动力学研究  

Investigation on the kinetics of rapid nitriding of 38 CrMoAl steel under vacuum electromagnetic induction

作　　者：杨峰[1] 赵驯峰 郑纪豹 冯治国 刘静[1] YANG Feng;ZHAO Xunfeng;ZHENG Jibao;FENG Zhiguo;LIU Jing(School of Materials and Architectural Engineering,Guizhou Normal University,Guiyang,Guizhou 550025,China;School of Materials and Metallurgy,Guizhou University,Guiyang,Guizhou 550025,China)

机构地区：[1]贵州师范大学材料与建筑工程学院,贵州贵阳550025 [2]贵州大学材料与冶金学院,贵州贵阳550025

出　　处：《贵州师范大学学报（自然科学版）》2021年第3期85-91,共7页Journal of Guizhou Normal University：Natural Sciences

基　　金：国家自然科学基金(51464008,51574096);贵州省科学技术基金(黔科合基础[2020]1Z041)。

摘　　要：为提高渗氮速率,明确氮化动力学机制,采用真空电磁感应渗氮技术研究38 CrMoAl钢在NH_(3)介质下的渗氮动力学过程。以显微硬度值550 HV_(0.025)对应的深度作为渗氮层评价指标,通过一种新的气固反应动力学模型对38 CrMoAl钢在温度为530~590℃范围内氮渗氮动力学行为进行研究。结果表明:38 CrMoAl钢在530~590℃范围内的真空电磁感应渗氮过程主要是受内扩散所控制,表观活化能E为76.736 kJ/mol。通过模型预测了各因素(活性氮浓度、温度、目标渗氮厚度等)对其渗氮反应分数ξ、特征时间t_(c)和转化速率dξ/dt的影响规律,发现增加活性氮浓度和反应温度均能提高渗氮转化过程中的反应分数和反应速率,其中温度的影响比浓度大;随着目标渗氮厚度的增加,反应所需的特征时间迅速增加;转化速率在不同条件下均随时间的增加而急剧降低。To improve the nitriding rate and clarify the nitriding kinetic mechanism,the nitriding kinetic process of 38 CrMoAl steel in NH 3 medium was studied by vacuum electromagnetic induction nitriding technology.A new gas-solid reaction kinetics model was used to study the kinetic nitriding of 38 CrMoAl steel in the temperature range from 530~590℃,and the depth corresponding to the microhardness value of 550 HV_(0.025) was used as the evaluation index of the nitriding layer.The results show that the vacuum electromagnetic induction nitriding process of 38 CrMoAl steel in the range of 530~590℃is mainly controlled by int ernal diffusion,and the apparent activation energy(E)is 76.736 kJ/mol.Meanwhile,the effects of various factors(reactive nitrogen concentration,temperature,target thickness of nitriding,etc.)on the nitriding reaction fraction factor(ξ),the characteristic time(t_(c)),and the conversion rate(dξ/d t)were predicted by the model.It found that the reaction fraction and reaction rate can be increased with the increase of reactive nitrogen concentration and reaction temperature in the process of transformation,and the effect of temperature is greater than that of concentration.Besides,with the increase of the target nitriding thickness,the characteristic time required for reaction increases rapidly.Moreover,the conversion rate decreased sharply with the increase of time under different_(c)onditions.

关 键 词：真空渗氮 电磁感应 转化速率 动力学 模型预测 

分 类 号：TG142.33[一般工业技术—材料科学与工程]