Effect of initial microstructure on mechanical properties in warm caliber rolling of high carbon steel

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Structural materials : properties, microstructure and processing, 2011-07, Vol.528 (18), p.5833-5839
• Main Authors: Oh, Y.S., Son, I.H., Jung, K.H., Kim, D.K., Lee, D.L., Im, Y.T.
• Format: Article
• Language: English
• Subjects: Applied sciences; Cementite; Elasticity. Plasticity; Exact sciences and technology; Field emission; High carbon steel; High carbon steels; Hot rolling; Initial microstructure; Mechanical properties; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Metals. Metallurgy; Microstructure; Strength; Submicron grain structure; Toughness; Warm caliber rolling
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2011.04.016

► The effect of initial microstructure on change of micro-hardness, tension, and Charpy tests were investigated by warm caliber rolling (WCR). ► Smaller ferrite grain and dispersed cementite particles with smaller interspacing increased the strength and toughness. ► In WCR, elongation hardly decreased compared to the conventional hot rolling. ► Depending on the microstructure change, WCR guaranteed higher impact energy and the mode of fracture varied as well. In this study, the effect of initial microstructure on change of mechanical properties was investigated by warm caliber rolling (WCR) of high carbon steel. Experiments were carried out with two different kinds of initial microstructures of pearlite and tempered martensite at the temperature of 500 °C. For comparison, the microstructure of austenite phase obtained from the conventional hot rolling at the temperature of 900 °C up to about 83% of the accumulative reduction in area was assumed to be a reference case. It was found that the WCR provided better mechanical properties in terms of strength and toughness compared to the conventional hot rolling based on experimental results of micro-hardness, tension, and Charpy impact tests. The improvement of strength and toughness was attributed to smaller ferrite grain and dispersed cementite particles with smaller interspacing aligned to the rolling direction after the WCR owing to field emission scanning electron microscopy. The investigated WCR might be useful in obtaining the high strength material with better toughness without adding new alloying elements for industrial applications according to the present investigation.