The Effects of Si and Deformation on the Phase Transformation in Dual Phase Steels

Sang Hwan Lee; Jong Min Choi; Yeol Rae Cho; Kyung Jong Lee

doi:10.4028/www.scientific.net/SSP.124-126.1617

Paper Titles

Microstructures and Tribological Properties of Plasma Arc Sprayed Al-Fe-Cr-Ti Quasicrystalline Coatings
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Variation of Corrosion Resistance and Hardness with Heat Treatment of ALDC8 Al Alloy
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Impact and Indentation Resistance of Superhard AlCrN Thin Films
p.1609

Shielding Effectiveness Simulation of Brass-Iron Sandwich Films
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The Effects of Si and Deformation on the Phase Transformation in Dual Phase Steels
p.1617

Characteristics of 2.45GHz Microwave Plasma by Langmuir Probe Measurements
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An Ab Initio Study of the Energies of Coherent Interfaces Formed between bcc Iron and Carbides or Nitrides of Transition Metals
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Competing Ion Effect of Stabilization by Cr(III) & Cr(VI) in Ettringite Crystal Structure
p.1629

Microscratch Analysis and Interfacial Toughness of Catalyst Coating on Electrolyte Polymer in Micro Fuel Cells
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The Effects of Si and Deformation on the Phase Transformation in Dual Phase Steels

Abstract:

The effect of Si on phase transformation was well known in dual phase steels. Si promoted the ferrite transformation and the enriched C in untransformed austenite prohibited the transformation at intermediate temperature range resulting in the formation of lower bainite and martensite at low temperature range. In addition, during continuous cooling with fast cooling rate, it was very hard to differentiate one phase from the others. In order to clarify the effects of Si on the austenite-to-ferrite transformation quantitatively, the start temperatures of bainite(BS) and martensite(MS) as well as ferrite(Ae3) and pearlite(Ae1) were calculated by thermodynamic analysis. LVDT measured by dilatometer and 1st differentiation peaks of LVDT were examined with microstructures, which gives a possibility of the phase separation. In CCT diagrams, it was also found that large austenite grain size(AGS) widened the gap between the transformation start(Ts) and end(Tf) when Si was added.