Abstracts Book - IMRC 2018

• SE5-P001
METALLOGRAPHIC, STRUCTURAL AND MECHANICAL
CHARACTERIZATION OF A LOW DENSITY Fe-Mn-Al-C STEEL
MICROALLOYED WITH Ti/B IN AS-CAST AND -HOMOGENIZED
CONDITIONS
Omar Enrique Villanueva Pérez 1 , Ignacio Mejía 1 , Víctor García García 1 , Arnoldo Bedolla
Jacuinde 2
1 Universidad Michoacana de San Nicolás de Hidalgo, Departamento de Metalurgia Mecánica-
IIMM, Mexico. 2 Universidad Michoacana de San Nicolás de Hidalgo, Departamento de
Fundición-IIMM, Mexico.
Low density (LD) steels have shown particular characteristics in terms of
mechanical properties and microstructure, since they have high strength, high
ductility and density reduction up to 18%. On the other hand, the addition of
microalloying elements such as Ti and B generate hardening by solid solution
and precipitation, as well as grain refinement effect. LD steels generate nanosized
kappa phase precipitated from the austenite matrix, and these advanced
steels can reach strength and elongation up to 780 MPa and 60%, respectively.
The main objective of this research work is the metallographic, structural and
mechanical characterization of a LD steel microalloyed with Ti/B in as-cast and -
homogenized conditions. For this purpose a Fe-27Mn-7Al-1.2C (%wt) LD steel
microalloyed with Ti/B was melted in a vacuum-induction furnace and cast in
metallic mold. LD-Ti/B samples were homogenized at 1100 °C during 20, 50, 100,
150 and 200 minutes followed by water quenching. Metallographic, structural
and mechanical characterization was carried out by optical (LOM) and scanning
electron (SEM) microscopy, X-ray diffraction (XRD) and microhardness Vickers
testing (HV10), respectively. In general, results showed a typical dendritic
microstructure with average grain size of 1256 µm in the as-cast condition. On
the other hand, the as-homogenized condition showed an austenitic equiaxial
microstructure with average grain size from 164 to 940 µm. Austenite, ferrite
and kappa phases were detected by means of X-ray diffraction (XRD). Also,
second-phase particles such as AlN, TiC and MnS were detected by LOM and
SEM-EDS analysis. LD steel microalloyed with Ti/B exhibited the highest
microhardness Vickers value (235 HV10) in the as-cast condition, whilst in the ashomogenized
condition microhardness gradually decreases from 223 to 198
HV10 as holding time increases.