The Novel Technique of Grain Refinement in the Aluminum-Free Ultrahigh Carbon Steel

• Published in: Steel research international Vol. 87; no. 11; pp. 1444 - 1449
• Main Authors: Liu, Qing Suo, Zhao, Mei Ju, Zhang, Hai Xia, Li, Na, Shi, Wei Dong, Wang, Jing
• Format: Journal Article
• Language: English
• Published: Weinheim Blackwell Publishing Ltd 01.11.2016; Wiley Subscription Services, Inc
• Subjects: Aluminum; aluminum-free UHCS; Carbides; Carbon steel; Eutectoid temperature; Fracture toughness; Grain refinement; Heat treatment; High carbon steels; Mechanical properties; Structural steels; three-parameter combination technique
• ISSN: 1611-3683; 1869-344X
• DOI: 10.1002/srin.201500426

In order to achieve high strength and toughness of the aluminum‐free ultrahigh carbon steel (UHCS), the effect of a novel three‐parameter combination technique including heating temperature, cooling rate, and isothermal eutectoid transformation time on the phase composition, grain morphology, and mechanical properties is investigated by X‐ray diffraction analysis, optical microscopy, and mechanical tests. The result shows that when the steel is cooled from 860 °C to the eutectoid transformation temperature with the rate of 1.0 °C s−1 and held for 1.5 h, the excellent mechanical properties are obtained due to the grain refinement of carbide and matrix. For the designed aluminum‐free UHCS, the structure can be refined by a simple three‐parameter heat‐treatment process. The process can suppress the precipitation of large blocky carbide and avoid the formation of pearlitic structure with larger interlamellar spacing. Therefore, the excellent mechanical properties can be obtained for the steel.