METHOD OF PRODUCING A PART WITH VERY HIGH MECHANICAL PROPERTIES FROM A ROLLED COATED SHEET

摘要

The invention relates to a method of producing a part with very high mechanical properties from a rolled coated sheet. According to the invention, more than 90 % of the thickness of a steel part is coated with a compound comprising at least a Fe-Zn-based phase having an iron weight percent content of no less than 65 % and a Fe/Zn ratio of between 1.9 and 4. The aforementioned compound is formed by at least one alloying heat treatment between the steel and a pre-coat, said pre-coat consisting of a zinc alloy containing between 0.5 and 2.5 wt.- % aluminium and optionally one or more elements selected from Pb = 0.003 wt.- %, Sb = 0.003 wt.- %, Bi = 0.003 wt.- %, 0.002 wt.- % = Si = 0.07 wt.- %, La < 0.05 wt.- %, Ce < 0.05 wt.- %, the remainder comprising zinc and inevitable impurities.