Comparison of Formability Performance Between CR550LA and CR590DP

While rapid development of advanced high strength steels (AHSS) for a safer and lighter vehicle has been a primary focus in the automotive industry, the application of traditional high strength low alloy (HSLA) steel continues to be actively supported and developed. AHSS are often used to replace HSLA steels for downgauging while maintaining similar or better performance in crashworthiness and durability. However, recent developments have enabled the availability of higher strength, cold-rolled HSLA steels that could offer opportunities for a more balanced solution between material cost and material performance. Certain higher strength HSLA steels not only offer a cost-effective way to increase the strength-to-weight ratio but also provide comparable formability and better weldability to AHSS. In this study, cold rolled HSLA grades of CR340LA, CR420LA, and CR550LA are evaluated in overall formability and in-use performance when compared to CR590 dual phase (DP) grade. The evaluations include both global and local formability tests such as the forming limit curve (FLC), the true fracture strain, the half specimen dome and the hole expansion tests. Additionally, component level feasibility is also evaluated using a lab forming simulative die. Experimental results indicate that CR550LA tends to have similar global formability but better local formability than CR590DP. These results demonstrate that these higher strength, cold-rolled HSLA steels can potentially be used to replace CR590DP for certain components.