Mechanical Characterization and Micro-structural Analysis of Plates Obtained by the Tailor Welded Blank process (TWB)

Abstract

One of the biggest challenges facing the auto industry globally is to develop vehicles that are both lightweight and mechanically resistant. Tailor Welded Blank (TWB) comes as a solution as it is a process that allows butt welding of sheets of different specifications (material, thickness and / or coating) prior to forming. In this research we worked with Interstitial Free (IF) steel plates of the Companhia Siderúrgica Nacional (CSN), with FEE 210 codes of 1.2 mm thickness and IF CSN FEP 05 of 0.7 mm thickness, welded. Laser Uniaxial tensile and Vickers microhardness tests were performed. The weld line was oriented from 0° to 70° (ranging from 5° to 5°). From the results obtained it is expected that a methodology can be consolidated to evaluate the best possible angle for the weld line of a TWB. It has been found that the maximum load supported increases as the weld line is tilted (up to a certain limit) and that additional bending angles generate similar shear loads. Then work with angles that allow optimization of mechanical strength, better conformability and greater mass and cost reduction. Selecting this angle will be tied to design issues.

Key-words:
Forming; Laser welding; Tailor Welded Blank; Auto industry