Transformation behavior of low carbon steels containing two different Si contents
Continuous cooling transformation behaviors of low carbon steels with two Si contents (0. 50% and 1. 35%) were investigated under undeformed and deformed conditions. Effects of Si contents, deformation, and cooling rates on y transformation start temperature (Ar3 ), phase microstructures, and hardness were studied. The results show that, in the case of the deformation with the true strain of 0. 4, the length of bainitic ferrite laths is significantly decreased in low Si steel, whereas, the M/A constituent becomes more uniform in high Si steel. An increase in cooling rates lowers the Ar3 greatly. The steel with higher level of Si exhibits higher Ar3, and higher hardness both under undeformed and deformed conditions compared with the steel with a lower Si content. Especially, the influence of Si on Ar3 is dependent on deformation. Such effects are more significant under the undeformed condition. The hardness of both steels increases with the increase of cooling rates, whereas, the deformation involved in both steels reduces the hardness.
Key wordsSi content low carbon steel cooling rate transformation behavior bainitic morphology
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- 2.KANG Yong-lin. Quality Control and Formability of Modern Automobile Sheet [M]. Beijing: Metallurgical Industry Press, 1999 (in Chinese).Google Scholar
- 4.Takechi H. Recent Progress in High Strength Steels for Automobile in Japan [J]. Iron and Steel, 2005, 40(Supplement): 58.Google Scholar
- 5.ZHOU Rong-feng, YANG Wang-yue, SUN Zu-qing, et al. Transformation Kinetics of Undercooled Austenite During Deformation of Low Carbon (Mn) Steels With Different Carbon and Manganese Contents [J]. Acta Metallurgica Sinica, 2004, 40(10): 1055 (in Chinese).Google Scholar
- 9.Lam R H, Yang J R. The Effect of Compressive of Austenite on the Bainitic Ferrite Transformation in Fe-Mn-Si-C Steels [J]. Materials Science and Engineering, 2000, 278A: 278.Google Scholar
- 10.LIU Shi-kai, YANG Liu. Influence of Si and Mn on Morphology of Bainitic Ferrite and Kinetics of Bainite Transformation in Fe-C Alloy [J]. Acta Metallurgica Sinica, 1992, 28(12): A513 (in Chinese).Google Scholar
- 13.Aaronson H I, Laughlin D E. Solid-Solid Phase Transformations [M]. New York: Metallurgical Society of AIME, 1982.Google Scholar