Abstracts Book - IMRC 2018

• SE5-O018
EVALUATION OF TWO DIFFERENT JOINT DESIGNS IN THE
THERMAL AFFECTION OF 2507 SUPERDUPLEX STAINLESS STEEL
WELDED WITH THE GMAW PROCESS.
Ricardo Arreola Rangel 1
1 Universidad Michoacana de San Nicolás de Hidalgo, Instituto de Investigación en Metalurgia y
Materiales, Mexico.
The main problem that arises during fusion welding is the thermal affectation of
the parent materials. In the particular case of stainless steels, susceptibility to
localized corrosion results around Cr-rich phases (sensitization) precipitated in
the heat affected zone (HAZ). Therefore, it is recommended to weld these
materials with low heat inputs. The present work evaluates the thermal affection
induced during gas metal arc welding (GMAW) of 2507 stainless steel plates, 6.35
mm in thickness, as a function of the joint design with a heat input of 1.2 kJ/mm.
The typical single V groove joint design with a toe of 2 mm and separation of 2.5
mm was compared with a joint design with a toe of 4.35 mm and separation of
3 mm, with a bevel of 60°. A filler wire ER-2209 was used along with 98%Ar -
2%O 2 as shielding gas. The characterization microstructural, mechanical and
double loop electrochemical potentiodynamic reactivation (DL-EPR) were
carried out on the HAZ and compared with the base material in the as-received
condition. It was possible to weld the joint design with the high toe (4.35 mm) in
a single welding pass leading to a reduced thermal affection and an improved
austenite/ferrite balance in comparison with the typical joint. In spite of these
characteristics, the results of the DL-EPR tests revealed a greater degree of
sensitization in the ZAT of the high toe joint design. This effect is due to the
different rates of cooling having constant heat input, that is to say, the high toe
joint design cools down at a slower rate and gives more time for precipitation of
detrimental phases in the HAZ.
Acknowledgment:
Author would like to appreciate the support from Universidad Autonoma de
Campeche (UACAM). Especially to the PhD. Dr. Luis Román Dzib Pérez and PhD.
Jorge Antonio González Sánchez from Centro de Investigaciones en Corrosión
(CICORR-UACAM). Provision of laboratory facilities during the period that this
research was conducted.