Header menu link for other important links
X

Evolution of microstructure and its influence on tensile properties in thermo-mechanically controlled processed (TMCP) quench and partition (Q&P) steel

R. Parthiban, Sandip Ghosh Chowdhury, ,
Published in Elsevier Ltd
2017
Volume: 705
   
Pages: 376 - 384
Abstract
Controlled hot rolling is performed on low carbon Q&P steel and is subsequently followed by a direct Q&P (DQP) treatment and a separate Q&P treatment (SQP). Two different levels of strain viz. 0.51 and 1.1 are accomplished in the thermomechanical controlled process (TMCP) prior to the Q&P treatment. The microstructures of the steels processed through both the DQP and SQP methods with different thickness reductions, contain primarily small lath packets with fine martensite laths and thin films of inter-lath austenite. Comparatively higher martensite volume fractions and fine lath packets is noticed in the DQP method. Tendency of higher retained austenite fraction is observed in the SQP method. Presence of a high fractions of high angle grain boundaries (HAGB) in the martensite laths indicates a fully recrystallized prior austenite grains in both steels. In general, prior thermo-mechanical treatment improves the partition kinetics which is supported by the high value of calculated carbon content of the austenite, Cϒ, in the DQP steels. Combination of TMCP and Q&P process has resulted in remarkable increase in strength with adequate ductility compared to a simple Q&P treatment alone. Maximum strength of about 1398 MPa with a total elongation of 14% is achieved in the 1.1DQP steel. The study suggests that performing a TMCP prior to Q&P promotes grain refinement and formation of high fractions of HAGBs that are beneficial to improve the tensile properties. © 2017 Elsevier B.V.
About the journal
JournalData powered by TypesetMaterials Science and Engineering A
PublisherData powered by TypesetElsevier Ltd
ISSN09215093
Open AccessNo
Concepts (19)
  •  related image
    Austenite
  •  related image
    Grain boundaries
  •  related image
    Grain refinement
  •  related image
    Hot rolling
  •  related image
    Low carbon steel
  •  related image
    Martensite
  •  related image
    Martensitic steel
  •  related image
    Microstructural evolution
  •  related image
    Microstructure
  •  related image
    Thermomechanical treatment
  •  related image
    Different thickness
  •  related image
    HAGBS
  •  related image
    High angle grain boundaries
  •  related image
    Martensite volume fraction
  •  related image
    Misorientation angle
  •  related image
    PRIOR AUSTENITE GRAINS
  •  related image
    Retained austenite
  •  related image
    TMCP
  •  related image
    Process control