Abstracts Book - IMRC 2018

• SE5-P010
QUANTIFICATION OF RETAINED AUSTENITE OF A TRIP STEEL
DURING COLD ROLLING
José Sergio Pacheco 1 , Jorge Antonio Navarro 2 , José Jaime López 3 , José de Jesus Cruz 4 , Pedro
Garnica 2
1 Universidad Autónoma de San Luis Potosí, DICIM, Mexico. 2 Instituto Tecnológico de Morelia,
División de Estudios de Posgrado e Investigación, Mexico. 3 Instituto Tecnológico de Morelia,
Ingeniería en Materiales, Mexico. 4 Universidad Autónoma de San Luis Potosí, Facultad de
Ingeniería-Instituto de Metalurgia UASLP, Mexico.
The objective of this work is to obtain a multiphase steel with TRIP behavior and
to evaluate the content of retained austenite after each cold rolling pass. In an
induction furnace, a commercial steel AISI-1018 was melted, to which ironmanganese
and iron-silicon were added, obtaining the chemical composition
0.21 %C, 1.22 %Mn, 2.16 %Si. The ingot obtained was sectioned in two parts and
hot-rolled at 63% reduction for subsequent air cooling. The transformation
temperatures A1 and A3 were determined by dilatometry, with which the TTT
and CCT diagrams were simulated. Using these diagrams, the heat treatment
consisting of a intercritical annealing and isothermal treatment was performed.
Test specimens were machined for the tension test according to the ASTM-E8
standard, as well as specimens (dimensions 5.9 x 10 x 30 mm) for cold rolling at
room temperature at six percent reduction. The results of the micrographs of
the specimens after the heat treatment show the presence of at least three
phases: ferrite, bainite, retained austenite/martensite. Using XRD, the presence
of retained austenite was identified and, using the direct comparison method, a
volume of 15.6% of retained austenite was determined, which was reduced to
7.1% after the stress test. The maximum resistance reached was 890 MPa and
30% elongation. The evaluation of the retained austenite after each pass rolling,
shows that 20% strain 45% of the volume of retained austenite is reduced.
Acknowledgment:
Al CONACYT, por la beca otorgada para el desarrollo de mi proyecto doctoral, al
Instituto de Metalurgia de la UASLP y al Instituto Tecnológico de Morelia por las
facilidades para el desarrollo del proyecto.
Keywords: TRIP steel, Plastic deformation, Cold lamination
Presenting authors email: spacheco_isa@yahoo.com.mx