1. Measurement

1.1 Hardening measurement

The particularity of measuring bake-hardening as age-hardening comes from the value of the reference stress, which can be the yield strength of the delivered sheet i.e. deformed only by skin-pass (roll-hardening pass), hardening sometimes called BH ₀ , or deformed by tension to simulate stamping. The yield strength gain (ΔR _e ) is the sum of the increase due to work hardening (WH) and aging proper (bake hardening (BH) (figure