Study on Welding-Seam Characteristics and Formation of Tailor-Welded Blanks with Big Unequal Thickness

170P1/DX54D+Z was a kind of laser-welding-tailored-blanks with unequal thickness. But it usually occurred poor welding seam especially when the thickness has an obvious difference. In this study, it was explored that the important influence factors of welding seam and formations based on the micro-hardness, microstructure testing and cupping experiment. The micro-hardness and microstructure of base metal，welding seam and heat affected zone (HAZ) has been observed. In addition, offset of welding seam and Erickson value was also measured. It was analyzed that the effect of the thickness difference and chemical compositions on welding seam and formation. It was stated that there were a great influence of thickness difference and chemical compositions on the properties of welding seam and formation.