Development of high strength hot rolled low carbon copper-bearing steel containing nanometer sized carbides

M. P. Phaniraj, Young Min Shin, Joonho Lee, Nam Hoon Goo, Dong Ik Kim, Jin Yoo Suh, Woo Sang Jung, Jae Hyeok Shim, In Suk Choi

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Abstract

A low carbon ferritic steel was alloyed with Ti, Mo and Cu with the intention of achieving greater increment in strength by multiple precipitate strengthening. The steel is hot rolled and subjected to interrupted cooling to enable precipitation of Ti-Mo carbides and copper. Thermodynamic calculations were carried out to determine equilibrium phase fractions at different temperatures. Microstructure characterization using transmission electron microscopy and composition analysis revealed that the steel contains ~5. nm size precipitates of (Ti,Mo)C. Precipitation kinetics calculations using MatCalc software showed that mainly body centered cubic copper precipitates of size <. 5nm form under the cooling conditions in the present study. The steel has the high tensile strength of 853. MPa and good ductility. The yield strength increases by 420. MPa, which is more than that achieved in hot rolled low carbon ferritic steels with only copper precipitates or only carbide precipitates. The precipitation and strengthening contribution of copper and (Ti,Mo)C precipitates and their effect on the work hardening behavior is discussed.

Original languageEnglish
Pages (from-to)1-8
Number of pages8
JournalMaterials Science and Engineering A
Volume633
DOIs
Publication statusPublished - 2015 May 1

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Keywords

  • Copper
  • HSLA steel
  • Interrupted cooling
  • Nano-sized carbides
  • Numerical simulation

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering
  • Mechanics of Materials

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