Journal of Northeastern University Natural Science ›› 2019, Vol. 40 ›› Issue (4): 483-487.DOI: 10.12068/j.issn.1005-3026.2019.04.06

• Materials & Metallurgy • Previous Articles     Next Articles

Production Technology of Low-C Medium-Mn Q690F High Strength and Toughness Mid-Thick Steel Plate

QI Xiang-yu1, ZHU Xiao-lei2, HU Jun1, DU Lin-xiu1   

  1. 1. State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang 110819, China; 2. State Key Laboratory of Metal Materials for Marine Equipment and Application, Iron & Steel Research Institutes of Ansteel Group Corporation, Anshan 114009,China.
  • Received:2018-01-30 Revised:2018-01-30 Online:2019-04-15 Published:2019-04-26
  • Contact: DU Lin-xiu
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Abstract: The thermomechanical control process(TMCP) and heat treatment test were conducted on low-C medium-Mn Q690F high strength and toughness mid-thick steel plate. The microstructure of the tested steel was analyzed and the tensile and impact properties were measured. The strengthening and toughening mechanisms were discussed. The results showed that the microstructure of the tested steel is a layered structure composed by sub-micrometer tempered martensite and reverse transformation austenite.The yield strength, tensile strength,elongation, and-60℃ impact energy of the tested plate at 1/4 thickness are 725MPa, 840MPa, 27.7%, 130J, respectively. The strain hardening caused by transformation induced plasticity(TRIP)from the reversed austenite is the main strengthening mechanism. The TRIP effect which absorbs a large amount of strain energy, delays the necking and increases the uniform elongation is considered as the main mechanism for plasticizing. Furthermore, the TRIP effect can increase the energy of the crack initiation and propagation effectively, it is also regraded as the main toughening mechanism.

Key words: medium-Mn steel, Q690F, TRIP effect, strengthening mechanism, plasticizing mechanism, toughening mechanism

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