Microstructural Evolution of 31CrMoV9 Steel upon Controlled Gaseous Nitriding Treatment
Microstructural Evolution of 31CrMoV9 Steel upon Controlled Gaseous Nitriding Treatment
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31CrMoV9 钢受控气体氮化处理的显微组织演变
DOI：
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发表时间：
2016
期刊：
影响因子：
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通讯作者：
E. Mittemeijer
中科院分区：
文献类型：
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作者：
C. Kang;S. Meka;T. Steiner;R. Schacherl;E. Mittemeijer
在550 °C的渗氮温度下，通过改变渗氮电位和渗氮时间，研究了调质31 CrMoV 9钢可控气体渗氮后组织和表面残余应力的演变。梯度显微组织发展为深度的函数：表面相邻脱碳-氮化区，其中所有回火诱导的碳化物已转化为氮化物，在通过表面释放的碳的损失下，随后是氮化区，其中从碳化物到氮化物转化释放的碳扩散到晶界并在那里沉淀为（新的）碳化物。脱碳的程度表现出强烈的依赖于是否存在外部铁氮化物化合物层，以及在试样表面存在的铁氮化物的类型。表面残余应力是渗氮时间和渗氮势的函数，并从碳化物向氮化物的转变速率、脱碳速率和/或碳化物沿沿着沉淀速率等方面进行了讨论。
Abstract The evolution of the microstructure and the surface residual stress upon controlled gaseous nitriding of quenched and tempered 31CrMoV9 steel was investigated by varying the nitriding potential and the nitriding time at the nitriding temperature of 550 °C. A graded microstructure developed as a function of depth: a surface adjacent decarburized-nitrided zone, in which all tempering induced carbides had trans-formed to nitrides, under loss of the released carbon through the surface, is followed by a nitrided zone in which the carbon released from the carbide-to-nitride transformation had diffused to grain boundaries and precipitated there as (new) carbides. The extent of decarburization showed a strong dependence on whether or not an outer iron-nitride compound layer was present, as well as on the type of iron nitride present at the specimen surface. The surface residual stresses varied as a function of nitriding time and nitriding potential which has been discussed in terms of the rates of the carbide-to-nitride transformation, the decarburization and/or the carbide pre-cipitation along the grain boundaries.