High toughness and multiphase microstructure transition product of carburizing steel by a novel heat treatment cooling process

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• 作者：Bo Jiang^a ; Zhen Mei^a ; Le-yu Zhou^a ; Guang-lei Liu^b ; Zhi-lin Wang^b ; Bin Huang^b ; Ya-zheng Liu^a ; ^{lyzh@ustb.edu.cn" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Carburizing steel ; Toughness ; Lower bainite ; Retained austenite
• 刊名：Materials Science & Engineering A
• 出版年：2016
• 出版时间：15 October 2016
• 年：2016
• 卷：675
• 期：Complete
• 页码：361-370
• 全文大小：4088 K

文摘

A novel heat treatment cooling process was applied to a Fe-0.27C-1.50Mn-1.7Si-0.35Cr-0.64Mo-1.50Ni-0.10 V (wt%) carburizing steel. The cooling process was designed based on the continuous cooling transformation (CCT) and time-temperature-transformation (TTT) analyses of the carburizing steel. Mechanical property results of the heat treatment samples show that the carburizing steels exhibit excellent toughness (118 J) which is superior to that of the traditional quenching process. Microstructural characterization indicates that high toughness of the carburizing steel subjected to the cooling heat treatment process results from a proper multiphase microstructure transition from the surface to the matrix of the steel. The key factors which greatly improve the toughness are the lower bainite consisting of fine ferrite laths and retained austenite films along the laths at the transition region and the carbide-free lower bainite at the matrix.