Abstract: The invention relates to a corrosion inhibitor for a metal material such as steel, of the type consisting of an aqueous solution containing an alkali metal nitrite, wherein said solution contains 0.01 to 0.3 mol/l of an alkali metal nitrite, 0.01 to 0.3 mol/l of an alkali metal phosphate, and phosphoric acid in a proportion of a quantity sufficient to maintain the pH of said solution, measured at ambient temperature, between 6.9 and 7.2.

Abstract: The process is characterized by the fact that, before drawing, a salt of the alkaline metal group formed by Li, Na, and K, and of an anion which is chemically inert with regard to the essential metal of the sheet chose from among the phosphates is deposited on the drawing tools. To deposit the salt, preferably, a solution of said salt is applied to the tools or to the sheet metal.

Abstract: The installation comprises a set of radial type cells (25a, 25b). The electrical supply of the strip (16) to be coated constituting the cathode is ensured by way of two electrically conducting deflector rollers (20) each mounted rotatably about an axle parallel to the axle of the drum (8) of the electrolysis cell. The deflector rollers (20) are arranged at least in part below the upper level of the drum (8) close to its outer surface. Two support rollers (21a, 21b) associated with each of the deflector rollers ensure the holding of the strip against the deflector roller over a substantial part of its periphery and as far as a zone close to the part of the outer surface of the drum (8) which is submerged in the electrolytic liquid (2). The invention applies in particular to the electrogalvanizing of a steel sheet.