Abstract: A steel sheet is provided with a coating providing sacrificial cathodic protection. The coating includes between 1 and 40% by weight zinc, between 0.01 and 0.4% by weight lanthanum, optionally up to 10% by weight magnesium, optionally up to 15% by weight silicon, and optionally up to 0.3% by weight, in cumulative amounts, of additional components, the remainder includes aluminum and unavoidable impurities or residual elements. A method of producing parts by hot or cold swaging and the parts which can be obtained in this way are also provided.

Abstract: The subject of the invention is the use of a treatment solution containing sulfate ions for treating the surface of a galvanized steel sheet for the purpose of reducing degradation of the coating during the operation of forming said sheet, and for the purpose of improving the temporary corrosion protection of said sheet. It also relates to a method of lubricating such a coated sheet.

Abstract: The invention concerns a plain or zinc-plated steel plate, additionally coated on at least one of its surfaces with a single zinc or zinc alloy layer containing 0.15 to 1 wt. % of a polymer consisting of 6 to 150 identical or different units of general formula: (CH2C(R)(CONH2))—, with R?H or CH3 and optionally comprising polyallyl units, and a method for making said plates by electroplating in sulphate baths.

Abstract: A method for forming a zinc oxalate coating on the surface of a strip or sheet of metal covered with a zinc or zinc alloy coating other than zinc/iron coatings, with the aid of an aqueous solution consisting of oxalic acid having a concentration of between 5.10?3 and 0.1 mole/l, and at least one compound and/or ion of an oxidant zinc metal having a concentration of between 10?6 and 10?2 mole/l, and possibly a wetting agent. The inventive method enables sheet metal to be treated at very high speeds without using large amounts of oxidant. It facilitates management of treatment baths. The invention can be used in the lubrication of sheet metal, especially for die stamping.

Abstract: A method for forming a zinc oxalate coating on the surface of a strip or sheet of metal covered with a zinc or zinc alloy coating other than zinc/iron coatings, with the aid of an aqueous solution consisting of oxalic acid having a concentration of between 5.10−3 and 0.1 mole/l, and at least one compound and/or ion of an oxidant zinc metal having a concentration of between 10−6 and 10−2 mole/l, and possibly a wetting agent. The inventive method enables sheet metal to be treated at very high speeds without using large amounts of oxidant. It facilitates management of treatment baths. The invention can be used in the lubrication of sheet metal, especially for die stamping.

Abstract: 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/m2. 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 Zn2+ ions without polarization. The hydroxysulphate deposit brings about a pre-lubricating effect applicable to operations for forming sheet metal.

Abstract: A bath of pH higher than 4 containing more than 1 mole/liter of Zn.sup.++ ions and at least one polyethylene glycol polymer of the general formula R.sup.1 --O(CH.sub.2 --CH.sub.2 --O).sub.n --R.sup.2, in which n.ltoreq.13 and in which the concentration of polymer in the bath is adapted to incorporate in the coat an organic compound having a content by weight greater than 0.1%, expressed as weight of carbon per unit weight of the coat. The bath is adapted to high current densities, and the coat applied on the steel sheet imparts both a leveling effect and an improvement of corrosion resistance.

Abstract: The invention relates to a process for depositing a thin adhesive coating of polypyrrole on the surface of an article made of oxidizable metal, by electropolymerization of an aqueous or aqueous-alcoholic electrolytic solution of pyrrole and/or of one or more substituted pyrroles, in which the anode of the electropolymerization device consists of the article made of oxidizable metal, in which the solution contains ions selected from the ions of formula: ##STR1## in which X is selected from O, S and NH,R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are selected, independently of each other, from --H, --Cl, --Br, --F, --I, --OH, --SH, --NH.sub.2, --CHO, --COOH, --SO.sub.3 H and derivatives thereof, aryl groups, C.sub.1 to C.sub.20 alkyl groups, aralkyl groups and alkylaryl groups, these groups possibly being substituted with one or more groups selected from --OH, --SH, --NH.sub.2, --CHO, --COOH, .dbd.O, --CONH.sub.2, --N(X,X',X").sup.+, epoxy or C.sub.1 -C.sub.6 alkoxy, or together possibly forming a ring structure.