White layer formation due to phase transformation in orthogonal machining of AISI 1045 annealed steel
White layer formation due to phase transformation in orthogonal machining of AISI 1045 annealed steel
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DOI：
10.1016/j.msea.2007.11.081
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发表时间：
2008-08-15
期刊：
影响因子：
6.4
通讯作者：
Watkins, Thomas R.
中科院分区：
文献类型：
--
作者：
Han, Sangil;Melkote, Shreyes N.;Watkins, Thomas R.
人们普遍认为，钢加工过程中形成的白色层主要是由快速加热和淬火引起的热致相变引起的。因此，通常认为如果刀具后刀面-工件界面处的温度超过钢的标称相变温度，则会形成白色层。然而，尚未尝试实际测量刀具侧面-工件界面处产生的温度并将其与相变的微观结构证据相关联。本文旨在通过适当设计的实验和分析来解决这些局限性。在不同切削速度和刀具后刀面磨损情况下对 AN 1045 退火钢进行正交加工试验。在加工过程中，使用裸露热电偶技术测量刀具侧面-工件界面处的温度。进行机加工亚表面的金相研究和 X 射线衍射 (XRD) 测量，分别确定白层的存在和深度，以及机加工表面层中残余奥氏体相的存在。数据分析表明，由于在低于钢的标称奥氏体化温度的温度下发生相变，会形成白色层。提出了导致该结果的可能原因。 (C) 2007 Elsevier B.V. 保留所有权利。
It is commonly believed that the white layer formed during machining of steels is caused primarily by a thermally induced phase transformation resulting from rapid heating and quenching. As a result, it is often assumed that if the temperature at the tool flank-workpiece interface exceeds the nominal phase transformation temperature for the steel, a white layer forms. However, no attempt has been made to actually measure the temperatures produced at the tool flank-workpiece interface and correlate it with microstructural evidence of phase transformation. This paper aims to address these limitations through suitably designed experiments and analysis. Orthogonal machining tests were performed on AN 1045 annealed steel at different cutting speeds and tool flank wear. During machining, temperature measurements at the tool flank-workpiece interface were made using an exposed thermocouple technique. Metallographic studies of the machined sub-surface and X-ray diffraction (XRD) measurements were performed to determine the presence and depth of white layer, and the presence of the retained austenite phase in the machined surface layer, respectively. Analysis of the data shows that the white layer can form due to phase transformation at temperatures below the nominal austenitization temperature of the steel. Possible causes of this result are presented. (C) 2007 Elsevier B.V. All rights reserved.