Effect of Direct Quenching on Microstructure and Mechanical Properties of a Wear-resistant Steel

• Published in: Acta metallurgica sinica : English letters Vol. 26; no. 4; pp. 390 - 398
• Main Authors: Song, Hongyu, Zhang, Shunhu, Lan, Liangyun, Li, Canming, Liu, Haitao, Zhao, Dewen, Wang, Guodong
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.08.2013; Springer Nature B.V
• Subjects: Abrasion resistant steels; Bainite; Carbides; Characterization and Evaluation of Materials; Chemistry and Materials Science; Corrosion and Coatings; Direct quenching; Electron back scatter; Heat treating; Impact strength; Martensite; Materials Science; Mechanical properties; Metallic Materials; Microstructure; Nanotechnology; Nucleation; Optical microscopes; Optical properties; Organometallic Chemistry; Quenching and tempering; Scanning electron microscopy; Spectroscopy/Spectrometry; Tempering; Tribology; Wear resistance; 力学性能; 扫描电子显微镜; 显微组织; 板条马氏体; 电子背散射衍射; 直接淬火; 耐磨钢; 透射电子显微镜; Direct quenching; Temper; Mechanical properties; Martensite packet; Lower bainite
• ISSN: 1006-7191; 2194-1289
• DOI: 10.1007/s40195-012-0183-4

A wear-resistant steel was hot rolled at the same finish temperature, and subsequently treated with conventional reheat quenching and tempering process （RQ＆T） and direct quenching and tempering process （DQ＆T）, respectively. The effect of direct quenching on the microstructure and mechanical properties was investigated in detail by using optical microscope, transmission electron microscope and scanning electron microscope equipped with electron backscattered diffraction. The results showed that the microstructures of both the RQ and DQ specimens were complex constituents of lath martensite and lower bainite. Compared with the RQ specimen, the lower bainite content in DQ specimen was much higher. Furthermore, the bainite in the DQ specimen extended into and segmented the prior austenite grains, which can decrease martensite packet size. The proportion of high-angle boundary in the DQ specimen was higher than that in the RQ specimen, which may improve the impact toughness. The carbides in DQ＆_T specimen were much finer and distributed even dispersively because direct quenching can retain substantive defects which may provide more nucleation sites for carbide precipitation in the tempering process. Besides, the mechanical properties of DQ and DQ＆T specimens were superior than those subjected to RQ and RQ＆T processes, respectively.