Surface effect of environmentally assisted corrosion growth of automotive welded steel performance

Abstract

Failure of steel in automobile industries due to environmentally assisted medium in service is alarming. In this study an effort has been made to investigate critically the corrosion induced performances of automotive welded part. The experimental correlation on the effect of corrosive media (NaCl and HCl solutions) on the base metal, heat affected zone (HAZ) and weld metal formed were examined using linear potentiodynamic polarization technique. The hardness, microstructural and phase rationale of the studied joint was evaluated using, diamond base indenter, Scanning electron microscope and x-ray diffractograms respectively. The results revealed that the base metal has no detrimental phase transformation unlike the HAZ and the weld joint region. The hardness value of 185 HV welded joint was obtained compared to 235.95 HV of base region. The corrosion propagation in the 3.5NaCl and 1 M HCl shows that pitting deterioration occurs at the welded position in all case as a result of the shift in grain refinement and micro-straining during welding process.