Arcelormittal

Sollac

Arcelormittal France

Sollac (societe Anonyme)

Alain Bello

Gerard Dugelay

Vivian Fabbri

Jacques Petitjean

Isabelle Marolleau

Sylviane Wajda

Joel Marsal

Marie Lombardi

Armand Rossi

Nicolas Kopytowski

Gérard Dugelay

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&#x2264;0.003%; Sb&#x2264;0.003%; Bi&#x2264;0.003%; 0.002%.&#x2264;Si&#x2264;0.070%; La&#x3c;0.05%; and Ce&#x3c;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.

Part with very high mechanical properties from a rolled coated sheet

The invention relates to a steel part coated with a compound consisting, over more than 90% of its thickness, of 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, said compound being formed by at least one heat treatment for alloying between said steel and a precoat, said precoat consisting of a zinc alloy comprising, the contents being expressed by weight, between 0.5 and 2.5% aluminum and, optionally, one or more elements chosen from: Pb&#x2266;0.003%; Sb&#x2266;0.003%; Bi&#x2266;0.003%; 0.002%&#x2266;Si&#x2266;0.070%; La&#x3c;0.05%; Ce&#x3c;0.05%, the balance consisting of zinc and inevitable impurities.

Method of producing a part with very high mechanical properties from a rolled coated sheet

The invention concerns a steel plate coated with a metal layer based on zinc and a zinc hydroxysulphate layer, whereof the surface density of sulphur is more than 0.5 mg/m . The invention also concerns a method for obtaining said plate by treating a zinc coated sheet metal: either in a highly alkaline sulphate solution under polarization; or in a sulphate solution containing Zn ions without polarization. The hydroxysulphate deposit brings about a pre-lubricating effect applicable to operations for forming sheet metal.

Zinc coated steel plates coated with a pre-lubricating hydroxysulphate layer and methods for obtaining same

An electrogalvanizing process, in which a strip is moved past an anode, plating solution is made to flow at a speed V with respect to the moving strip, and an electric current of current density J greater than 50 A/dm.sup.2 is passed between the strip and the anode, which comprises carrying out the deposition under conditions such that: J/J.sub.lim is less than or equal to 0.15; J.sup.2 /J.sub.lim is less than or equal to 22 A/dm.sup.2 ; where J.sub.lim is the limiting current density, corresponding to the current density plateau in the current versus potential curve characteristic of the plating solution flowing at the speed V in the vicinity of the strip. An electroplating cell of the radial type for implementing the process, in which cell the anode bed is continuous, is disclosed. The process facilitates the high-speed deposition of zinc which has low rugosity and is free of edge dendrites.

Continuous process for the electrogalvanizing of metal strip in a

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Hettange-Grande, France

Alain Bello