Influencing on liquid quenching by surface structuring
Influencing on liquid quenching by surface structuring
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DOI：
10.1016/j.ijthermalsci.2015.10.025
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发表时间：
2016-03
影响因子：
4.5
通讯作者：
N. Kozlov;O. Kessler
中科院分区：
文献类型：
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作者：
N. Kozlov;O. Kessler
淬火是金属零件热处理中的重要工序。这通常是在蒸发液体(如水)中浸泡淬火。水中淬火的特点是作用力相对较小，平均淬火速率较高。这种方法的缺点是会出现莱登弗罗斯特效应。莱登弗罗斯特效应表现在热部件表面形成了一层薄薄的蒸汽膜，大大减少了部件与淬火介质之间的热流。根据成分几何形状和淬火条件的不同，汽膜在不同的时间和位置坍塌。这会导致部件变形和残余应力。许多关于莱登弗罗斯特效应的研究都涉及淬火介质和淬火条件的影响。在这项工作中，作为一种新的方法，研究了部件表面结构对淬火动力学的影响。工作的重点是研究在车削过程中可能产生的表面结构。在水中，利用具有特定沟槽表面结构的铝和钢部件进行了研究。表面结构的几何形状是不同的。评估是基于时间-温度测量和湿润锋面观测。研究发现，刻意的表面结构对淬火动力学有较大的影响。证实了通过与成分几何形状相适应的表面结构使淬火过程均质化的可能性。这表明在蒸发液体中浸泡淬火的均质化潜力很高。
Quenching is an important process in the heat treatment of metallic components. This is usually performed as immersion quenching in vaporizing liquids, such as water. Quenching in water is characterized by relatively small effort and high average quenching rate. Disadvantage of this method is the occurrence of the Leidenfrost effect. The Leidenfrost effect manifests itself in the fact that a thin vapour film is formed on the hot component surface, which greatly reduces the heat flow between the component and the quenching medium. Depending on the component geometry and quenching conditions the vapour film collapses at different time and location. This causes component distortion and residual stresses. Many studies on the Leidenfrost effect are dealing with influences of quenching medium and quenching conditions. In this work, the influence of component surface structure on the quenching kinetic has been investigated as a novel approach. The focus of the work is on the investigation of surface structures, which can be produced during the turning process. The investigation was made in water by means of aluminium and steel components with defined groove surface structures. Geometry of the surface structure was varied. The evaluation was based on time-temperature measurements, and rewetting front observations. It was found that the purposefully structured surface can affect quenching kinetic considerably. The possibility to homogenize the quenching process by surface structuring adapted to component geometry was confirmed. This indicates a high potential for homogenizing of immersion quenching in vaporizing liquids.