Use of Continuously Annealed Bake Hardenable Steels for Automobile Outer Panels

The automotive industry's ongoing effort to improve quality and reduce weight without added cost has led to the investigation of many medium strength steels. This study presents a comparison of continuously annealed Bake Hardenable Steels (BHS) with current DQSK production materials for outer panel applications.

While all steels exhibit strength increases from work hardening during forming, BHS has a unique and ideal characteristic which produces an increase in yield strength due to strain aging during the paint baking process at the automotive assembly plants. This results in an increase in dent resistance.

BHS is a desirable material for relatively flat outer panels which often receive only small strains during forming such as in doors, hoods and decklids. Improved durability against dents, dings, and palm printing are obtained in the BHS parts. Similarly, quality improvements are realized in the stamping and assembly plants by a decrease in handling and transit damage.