Vargas Cortes, Victor Hugo; Altamirano Guerrero, Gerardo; Mejia Granados, Ignacio; Baltazar Hernández, Víctor Hugo; Maldonado Zepeda, Cuauhtemoc
Resumen:
The combination of high strength and formability of transformation induced plasticity (TRIP)
steels is interesting for the automotive industry. However, the poor weldability limits its industrial
application. This paper shows the results of six low-alloy TRIP steels with di erent chemical
composition which were studied in order to correlate retained austenite (RA) and non-metallic
inclusions (NMI) with their resistance spot welded zones to their joints’ final mechanical properties.
RA volume fractions were quantified by X-ray microdi raction ( SXRD) while the magnetic saturation
technique was used to quantify NMI contents. Microstructural characterization and NMI of the
base metals and spot welds were assessed using scanning electron microscopy (SEM). Weld nuggets
macrostructures were identified using optical microscopy (OM). The lap-shear tensile test was used
to determine the final mechanical properties of the welded joints. It was found that NMI content in
the fusion zone (FZ) was higher than those in the base metal and heat a ected zone (HAZ). Whereas,
traces of RA were found in the HAZ of highly alloyed TRIP steels. Lap-shear tensile test results
showed that mechanical properties of spot welds were a ected by NMI contents, but in a major way
by the decomposition of RA in the FZ and HAZ.