Influence of Surface Preparation on the Kinetics of Controlled Gas-Nitrided AISI H13 Steels Used in Extrusion Dies
Influence of Surface Preparation on the Kinetics of Controlled Gas-Nitrided AISI H13 Steels Used in Extrusion Dies
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DOI：
10.1007/s11665-009-9496-5
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发表时间：
2010-04
影响因子：
2.3
通讯作者：
S. S. Akhtar-S.;A. Arif;B. Yilbas;A. Sheikh
中科院分区：
文献类型：
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作者：
S. S. Akhtar-S.;A. Arif;B. Yilbas;A. Sheikh
在铝挤压实践中，气体渗氮是提高AISI H13钢模具使用寿命的重要因素。据观察，如果模具轴承表面氮化前没有充分的准备，一个不均匀的和浅的氮化层开发与降低硬化效果。本文的重点是研究不同的表面条件下的粗糙度的氮化层的动力学发展过程中的气体渗氮过程中控制氮化电位的影响。考虑了由适当热处理（淬火和回火）的AISI H13钢制成的四个样品：没有表面处理、研磨、抛光和研磨。所有样品在相同条件下进行气体氮化，并在氮化后进行检查。氮化层，其特征在于使用不同的技术，包括光学显微镜，扫描电子显微镜，X-射线衍射分析，能量色散光谱映射，和显微硬度分析。结果表明，渗氮前的表面处理显著提高了渗氮动力学，从而导致均匀和深的渗氮层深度。与未制备的样品相比，由于增加的深度硬化效应，这提供了高的承载能力。与未制备的样品相比，获得了较薄且均匀的化合物层，相分离良好。
In the aluminum extrusion practice, gas nitriding represents an important factor in enhancing the service life of AISI H13 steel dies. It is observed that if the die-bearing surface is not adequately prepared before nitriding, a nonuniform and shallow nitrided layer develops with reduced hardening effect. The focus of this paper is to investigate the influence of different surface conditions in terms of roughness on the kinetics of nitrided layer developed during gas-nitriding process under controlled nitriding potential. Four samples made of AISI H13 steel properly heat treated (quenched and tempered) were considered: without surface preparation, ground, polished, and lapped. All the samples were gas nitrided under the same conditions and examined after being nitrided. The nitrided layers were characterized using different techniques including optical microscopy, scanning electron microscopy, x-ray diffraction analysis, energy dispersive spectrometry mapping, and microhardness analysis. It was found that the surface preparation prior to nitriding significantly enhanced the nitriding kinetics, which in turn resulted in even and deep nitrided case depth. This provided high load-bearing capacity due to increased and deep hardening effect as compared to unprepared sample. A thinner and uniform compound layer with well-resolved phases was achieved in comparison with unprepared sample.