Arcelormittal France

Arcelormittal Atlantique Et Lorraine

Sollac

Usinor

Arcelormittal

Jean-Pierre Laurent

Jacques Devroc

Dominique Spehner

Antoine Moulin

Jean-Louis Hochard

Jean-Paul Hennechart

Jacques Corquillet

Nathalie Romanowski

Xavier Bano

A steel part having a homogeneous multiphase microstructure in each region of the part, the microstructure containing ferrite, wherein the steel part is obtained by a process involving:

Method for making a steel part of multiphase microstructure

Hot-rolled steel sheet which then can be cold-rolled, coated, the steel in the sheet having the following composition by weight:

Coated hot- and cold-rolled steel sheet comprising a very high resistance after thermal treatment

The subject of the invention is a process for manufacturing a part made of steel having a multiphase microstructure, said microstructure comprising ferrite and being homogeneous in each of the regions of said part, which process comprises the steps consisting in:

The invention relates to a process for manufacturing a part having very high mechanical properties from a hot-rolled or cold-rolled steel strip, comprising precoating said strip with aluminum or an aluminum alloy, cold deformation of the coated strip, possible cutting of the excess sheet with a view to the final geometry of the part, heating of the part so as to form an intermetallic compound from the steel/precoat interface and to austenitize the steel, transfer of the part to a tool and cooling of the part in the tool at a rate such that the steel has, after being cooled, a martensitic or bainitic structure or a martensite-bainite structure. The precoating is carried out by electroplating, by chemical or physical vapor deposition or by co-rolling.

Method for making a coated steel part having very high resistance after heat treatment

Hot-rolled steel with very high elasticity limit and mechanical resistance usable in particular for auto parts production

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Arles, France

Jacques Devroc