Effects of Si on microstructural evolution and mechanical properties of hot-rolled ferrite and bainite dual-phase steels

Ming Hui Cai, Hua Ding, Young Kook Lee, Zheng You Tang, Jian Su Zhang

Research output: Contribution to journalArticle

36 Citations (Scopus)

Abstract

Based on the thermo-mechanical controlled process, the effects of Si on microstructural evolution, tensile properties, impact toughness, and stretch-flangeability of ferrite and bainite dual-phase (FBDP) steels were systematically investigated. The addition of Si from 0 to 0.95% promoted the formation of fine and equiaxed ferrite grains, and high Si (0.95%) also resulted in the formation of blocky martensite islands and retained austenite. Yield and tensile strengths, and uniform and total elongations all increased with increasing Si content. Therefore, the tensile strength and ductility balance was improved by Si addition due to the increasing strain-hardening rate. The fractured morphologies after hole-expansion showed that the excellent stretch-flangeability of FBDP steels was associated with the micro-cracks propagating through in ferrite phase as well as the elongated ferrite grains along the direction perpendicular to the crack. 0.95% Si steel had a similar high combination of tensile strength and impact toughness to 0.55% Si steel, and especially 0.95% Si steel exhibited an excellent combination of tensile strength and stretch-flangeability.

Original languageEnglish
Pages (from-to)476-481
Number of pages6
JournalISIJ International
Volume51
Issue number3
DOIs
Publication statusPublished - 2011 Jul 11

All Science Journal Classification (ASJC) codes

  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry

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