ArcelorMittal S.A.
Part with very high mechanical properties from a rolled coated sheet

Abstract:

The present invention provides a steel part. The steel part includes a steel precoated with a zinc-based alloy including, the contents being expressed by weight, from 0.5 to 2.5% aluminum and, optionally, one or more elements chosen from the group of: Pb.ltoreq.0.003%; Sb.ltoreq.0.003%; Bi.ltoreq.0.003%; 0.002%..ltoreq.Si.ltoreq.0.070%; La<0.05%; and Ce<0.05%. A balance of the precoat includes zinc and inevitable impurities. The steel part also includes a compound formed by at least one heat treatment for alloying between the steel and the precoat. The compound includes over more than 90% of its thickness, at least one Fe/Zn-based phase, the iron weight content of which is equal to 65% or higher and the Fe/Zn ratio of which is between 1.9 and 4. A structural or safety part is also provided.