A study on characteristics and evaluation of Mash Seam TB weld in ultra-low carbon steel applied on automotive body

극저탄소 냉연강판의 Mash Seam TB를 이용한 용접 시 특성과 평가에 관한 연구

This study introduces the new way for the evaluation criteria of the Mash-Seam Tailored Blank weldability, The materials used are low carbon automotive galvanized and high strength steels and the evaluation of weldability are examined with various thickness. Welding tests were conducted for both similar thickness and dissimilar thickness cases. The criteria developed for optimum welding conditions were based on the relationship among results of die press forming test, forming limit diagram, Erichsen test and microhardness measurements. The application of the developed criteria(fracture ratio, strength ratio, etc) in obtaining optimum welding condition revealed that a weld which satisfied ant of the criteria did not fracture during actual die press test and FLD dome test.