The main objective of this research is experimental and comparative investigation of mechanical properties, the failure modes of galvanized carbon steel butt arc welded joints by using experimental and numerical approaches. These approaches are; visualization inspection, tensile test, digital image correlate, free vibration analysis, chemical composition, bond strength and microstructural analysis which used in this study. Variations in grain size were observed in whole of sample for both weld and notweld specimens which state Steam heated specimens have great effects on grain structure. As the duration steam heated time increasing grain structure become change from fine to large and coarse size. Metallurgical investigations have been performed on weld with steam heated and not heated cases of samples in order to determine failure mechanism, microstructure and mechanical properties. The determined mechanical properties were evaluated at 6.51KN form tensile test and the values were observed as ultimate tensile strength 369 Mpa, yield strength 162 Mpa for notweld and 425Mpa, 208Mpa for welded specimens, respectively. Structural studies around inherent characteristics including natural frequencies can lead to a straight forward solution for detecting any types of imperfections in sample due to high deformation and natural frequency changes. This indicate, the strength of material decreasing from initial to final cases and also grate variation between weld and not weld specimen from before steam unheated to after steam heated cases.