Weld Associated Localized Necking during Fabrication of Dual Phase Steel Wheel Rims

High strength steels, such as the dual phase steels and high strength, low alloy steels, offer potential for wheel weight reduction but have been used sparingly, in part, because of a special problem that is unique to wheel rim fabrication. Compared to plain carbon steel, these steels have a higher tendency for weld related neck formation during rim fabrication and this contributes to a higher production scrap rate. This paper investigates mechanical property and microstructural changes produced in the flash butt welded, heat affected zone of one commercially available dual phase steel. Heating conditions most likely to increase the tendency for localized necking are identified. Micro-structural phenomena that might be responsible for the problem are discussed and plausible solutions are suggested.