Bake Hardening Steels
Traditional steels for car bodies can be bake hardened in the painting process
- interstitials diffuse to dislocations
- typical yield strength 255MPa
- Purposefully introducing nitrogen increases strength to 415-480MPa
However, most steel strip is now produced by continuous casting as a killed steel (i.e. aluminium is added) which is more consistent
- aluminium ties up nitrogen
- bake hardening is less effective