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Metallurgical and Materials Transactions A

, Volume 26, Issue 5, pp 1093–1100 | Cite as

Transformation strengthening by thermomechanical treatments in C-Mn-Ni-Nb steels

  • Sunghak Lee
  • Dongil Kwon
  • Young Kook Lee
  • Ohjoon Kwon
Mechanical Behavior

Abstract

The purpose of this study is to clarify the correlation between microstructural factors and mechanical properties of ultrafine steels processed by thermomechanical controlled treatments. Three steels deformed at high strain rates in a pilot plant rolling mill showed very fine ferritic microstructure, whose grains became more equiaxed and finer with increasing fraction of alloying elements, and had good tensile and fracture properties, although they contained only about 0.01 pct carbon. Especially in the Ni-added steel, tensile properties were greatly improved because of the high dislocation density and the fineness of the ferritic substructure, readily satisfying the requirements for commercial-grade high-strength, high-toughness steels. The formation of ultrafine equiaxed grains in the steels might be explained by a possible strain-induced dynamic transformation mechanism associated with the austenite → ferrite transformation caused by heavy deformation in the austenite range.

Keywords

Ferrite Austenite Material Transaction Bainite High Dislocation Density 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© The Minerals, Metals & Material Society 1995

Authors and Affiliations

  • Sunghak Lee
    • 1
  • Dongil Kwon
    • 2
  • Young Kook Lee
    • 3
  • Ohjoon Kwon
    • 4
  1. 1.Department of Materials Science and EngineeringPohang University of Science and TechnologyPohangKorea
  2. 2.Department of Metallurgical EngineeringSeoul National UniversitySeoulKorea
  3. 3.Department of Metallurgical EngineeringYonsei UniversitySeoulKorea
  4. 4.Steel Products DivisionResearch Institute of Industrial Science and TechnologyPohangKorea

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