Abstracts Book - IMRC 2018

• SE5-O017
MICROSTRUCTURAL AND MECHANICAL CHARACTERIZATION OF
AUTOGENOUS GTAW WELD IN HIGH-Mn AUSTENITIC Ti-
CONTAINING TWIP STEEL WITH THERMAL ANALYSIS
Víctor García García 1 , Ignacio Mejía 1 , Francisco Reyes Calderón 2
1 Universidad Michoacana de San Nicolás de Hidalgo, Departamento de Metalurgia Mecánica-
IIMM, Mexico. 2 Instituto Tecnológico de Morelia, Departamento de Metalmecánica, Mexico.
The welding heat input has been pointed out as a main limiting factor for
TWinnig Induced Plasticity (TWIP) steel weldability. Scarce research works have
been focused on the study of application and effects of the Gas Tungsten Arc
Welding (GTAW) process in the TWIP steel, particularly in higher thickness plate.
The present study conducted a detailed analysis of a butt weld joint carried out
in plates of TWIP steel microalloyed with titanium (TWIP-Ti) of 6.3 mm thickness.
The autogenous GTAW process with low heat input was applied. This analysis
considered grain size measurements, second-phases identification, postweld
mechanical properties (microhardness) and the welding thermal field. A finite
element model (FEM), validated with experimental results of thermal history,
allowed correlating metallurgical results with the thermal field. Likewise, the
prediction of phases during solidification carried out by means of JMatPro 9.0
software as well as the particles precipitation estimations were in good
agreement with the experimental results. These predicted diagrams were
calculated taking into account the TWIP-Ti steel chemical composition, different
grain sizes measured in critical weld regions and experimental cooling rates. The
low heat input improved the microstructural conditions in the heat affected
zone (HAZ) whose average grain size and precipitate particles, like (C, N)Ti,
promoted good mechanical properties as compared to the base material (assolution
condition). Some particles like Al 2 O 3 y MnS produced microporosities in
the HAZ. Despite this, the weld joint did not present hot cracking in the fusion
zone (FZ)-HAZ interface.
Acknowledgment:
Authors would like to thank the National Council on Science and Technology
(Consejo Nacional de Ciencia y Tecnología-México) for the support during the
project CB-2012-01-0177572. The present research project was also supported
by the Coordinación de la Investigación Científica-UMSNH (México) (CIC-1.8).