Fabrication of bake hardened steel strip for the production of automotive structural and appearance components, with or without anti-corrosion coatings

摘要

The fabrication of bake hardened steel strip comprises: (a) production of a steel with a given composition; (b) casting a slab of this steel, then hot rolling to produce a strip, the end rolling temperature being greater than the Ar3 point; (c) reeling of the strip at a temperature between 500 and 700 degrees C; (d) cold rolling the strip with a reduction rate of 50 to 80 %; (e) continuous annealing heat treatment with a duration of less than 15 minutes; (f) cold drawing with a reduction rate of between 1.2 and 2.5 %. Independent claims are also included for: (i) a bake hardened steel strip produced by this method; (ii) a component able to be cut from such steel strip, then painted and heated to at least 200 degrees C.