Method for producing shaped elements from sheet steel galvanized on one or both sides

A method of producing shaped articles made from single-sidedly or double-sidedly galvanized steel sheet, comprising:

• (1) applying a corrosion preventive oil to the surface of a galvanized steel strip in an amount of 0.25 to 5 g/m2,
• (2) transporting the oiled, galvanized steel strip to a fabrication site for shaped articles, and
• (3) separating and forming the oiled, galvanized steel strip into shaped articles made from single-sidedly or double-sidedly galvanized steel sheet, the corrosion preventive oil comprising:
• 50 to 99.5% by weight of at least one oil (A) having a flash point of at least 180° C.,
• 0.5 to 50% by weight of at least one active corrosion inhibitor substance (B), and
• 0 to 30% by weight of further additives (C),
• the percentages being based in each case on the total amount of all of the components of the corrosion preventive oil, wherein at least one of the active corrosion inhibitor substances (B) is an active substance (B1) of the general formula R1—CO—N(R2)—(CH2)n—COOR3, the definitions of the radicals and indices R1, R2, R3, and n being as follows:
• R1:
• a saturated or unsaturated, linear or branched hydrocarbon radical having 10 to 20 carbon atoms,
• R2:
• H or a linear or branched C1 to C4 alkyl radical,
• R3:
• H or a cation 1/m Ym+, where m is a natural number from 1 to 3, and
• n:
• a natural number from 1 to 4,
• with the proviso that at least 0.5% by weight of the active substance (B1) is used.

A shaped article made from single-sidedly or double-sidedly galvanized steel sheet, comprising a film of a corrosion preventive oil applied to the galvanized surface in an amount of 0.25 to 5 g/m2, the corrosion preventive oil being a formulation comprising

• 70 to 90% by weight of at least one oil (A) having a flash point of at least 180° C.,
• 10 to 30% by weight of at least one active corrosion inhibitor substance (B), and
• 0 to 20% by weight of further additives (C),
• the percentages being based in each case on the total amount of all of the components of the corrosion preventive oil, wherein at least one of the active corrosion inhibitor substances is an active substance (B1) of the general formula R1—CO—N(R2)—(CH2)n—COOR3, the definitions of the radicals and indices R1, R2, R3, and n being as follows:
• R1:
• a saturated or unsaturated, linear or branched hydrocarbon radical having 10 to 20 carbon atoms,
• R2:
• H or a linear or branched C1 to C4 alkyl radical,
• R3:
• H or a cation 1/m Ym+, where m is a natural number from 1 to 3, and
• n:
• a natural number from 1 to 4.

A method of corrosion protection in the course of storage and/or transport of a shaped article made from single-sidedly or double-sidedly galvanized steel sheet, comprising:

• applying to the shaped-article surface of the oil in an amount of 0.25 to 5 g/m2, the corrosion preventive oil being a formulation comprising
• 70 to 90% by weight of at least one oil (A) having a flash point of at least 180° C.,
• 10 to 30% by weight of at least one active corrosion inhibitor substance (B), and
• 0 to 20% by weight of further additives (C),
• the percentages being based in each case on the total amount of all of the components of the corrosion preventive oil, wherein at least one of the active corrosion inhibitor substances (B) is an active substance (B1) of the general formula R1—CO—N(R2)—(CH2)n—COOR3, the definitions of the radicals and indices R1, R2, R3, and n being as follows:
• R1:
• a saturated or unsaturated, linear or branched hydrocarbon radical having 10 to 20 carbon atoms,
• R2:
• H or a linear or branched C1 to C4 alkyl radical,
• R3:
• H or a cation 1/m Ym+, where m is a natural number from 1 to 3, and
• n:
• a natural number from 1 to 4.

A method of testing a galvanized steel sheet for its resistance to black-spot corrosion, comprising:

• (a) storing the galvanized steel sheet horizontally in a controlled-climate chamber;
• (b) sprinkling the galvanized steel sheet with salt-containing test particles with a diameter of 0.1 to 1 mm in an amount of 1000 to 25 000 particles/m2, so that the particles lie essentially each individually on the surface of the galvanized steel sheet to form a treated sheet;
• (c) storing the treated sheet for a defined time and temperature at a relative humidity of 75% to 95%;
• and
• (d) inspecting the surface of the treated sheet for corrosion around the test particles.