Formability of tailor-welded strips and progressive forming test

Tailor-welded blanks have been widely used in automotive industries. Tailor-welded strips are new type of strip materials for progressive forming. Dome test has been conducted to investigate the formability of tailor-welded strips (TWS) of four combinations. The FLD curve levels are found depend on the weak base material. The deformation of LDH test is modeled. The proposed critical yielding ratio and strength ratio effect are confirmed by both numerical simulations and dome tests. A bulb shield product, which is originally made from a stainless strip material, has been produced successfully from TWS materials by a progressive die. SAE J577 vibration tests on the TWS parts show around 40% vibration endurance improvement over the part made from stainless material. Since the stainless steel can be replaced by combination of thinner cold-rolled steel and high-strength steel, tailor-welded strips provide a promising potential to reduce both weight and cost for the progressive formed parts.