There is provided a method for manufacturing a galvanized steel sheet that has low sliding resistance in press forming and good degreasing property even under severe alkaline degreasing treatment conditions due to low temperature and short process line length. An oxide layer formed on the surface of a galvanized steel sheet is subjected to neutralization treatment using an alkaline aqueous solution containing 0.01 g/L or more of P ions and 0.01 g/L or more of colloid dispersed particles, wherein the alkaline aqueous solution preferably contains at least one phosphorus compound selected from phosphates, pyrophosphates, and triphosphates and at least one type of colloid dispersed particles selected from Ti, silica, Pt, Pd, Zr, Ag, Cu, Au, and Mg.

Coating materials with minimized lubricant demand enable optimized tribological conditions in forming flat steel products and are also unobjectionable in relation to their effects on the environment. With such coating materials, steel components can be produced by forming flat steel products in forming machines. For example, a tribologically-active layer may be produced on at least one surface of a flat steel product or a forming machine used to form the flat steel product, wherein the at least one surface comes into contact with the opposing component during forming. The tribologically-active layer may be formed by coating the at least one surface with a coating material from a group consisting of aluminum sulfate, ammonium sulfate, iron sulfate, and magnesium sulfate. The flat steel product may be inserted into the forming machine to be formed into the steel component.”

Coating materials with minimized lubricant demand enable optimized tribological conditions in forming flat steel products and are also unobjectionable in relation to their effects on the environment. With such coating materials, steel components can be produced by forming flat steel products in forming machines. For example, a tribologically-active layer may be produced on at least one surface of a flat steel product or a forming machine used to form the flat steel product, wherein the at least one surface comes into contact with the opposing component during forming. The tribologically-active layer may be formed by coating the at least one surface with a coating material from a group consisting of aluminum sulfate, ammonium sulfate, iron sulfate, and magnesium sulfate. The flat steel product may be inserted into the forming machine to be formed into the steel component.”

Provided is a surface treatment solution composition comprising: 30 to 51 wt % of a trivalent chromium compound comprising chromium phosphate (A) and chromium nitrate (B) and having a content ratio of A/(A+B) that satisfies 0.3 to 0.6; 5 to 15 wt % of silane coupling agent; 0.2 to 3 wt % of vanadium-based anti-corrosive rust inhibitor; 3 to 12 wt % of colloidal silica; 0.5 to 5 wt % of polysiloxane copolymer; and 14 to 61.3 wt % of water, a hot dip galvanized steel sheet surface-treated using same, and a manufacturing method thereof. The hot dip galvanized steel sheet treated with the surface treatment solution composition containing trivalent chromium has an excellent corrosion resistance, blackening resistance, pipe-forming oil reactivity, and alkali resistance.

A steel substrate coated on at least one of its faces with a metallic coating based on zinc or its alloys wherein the metallic coating is itself coated with a zincsulphate-based layer—includes at least one of the compounds selected from among zincsulphate monohydrate, zincsulphate tetrahydrate and zincsulphate heptahydrate, wherein the zincsulphate-based layer has neither zinc hydroxysulphate nor free water molecules nor free hydroxyl groups, the surface density of sulphur in the zincsulphate-based layer being greater than or equal to 0.5 mg/m.sup.2. A corresponding treatment method is provided.

A steel substrate coated on at least one of its faces with a metallic coating based on zinc or its alloys wherein the metallic coating is itself coated with a zincsulphate-based layer—includes at least one of the compounds selected from among zincsulphate monohydrate, zincsulphate tetrahydrate and zincsulphate heptahydrate, wherein the zincsulphate-based layer has neither zinc hydroxysulphate nor free water molecules nor free hydroxyl groups, the surface density of sulphur in the zincsulphate-based layer being greater than or equal to 0.5 mg/m.sup.2. A corresponding treatment method is provided.

A steel substrate is provided, coated on at least one of its faces with a metallic coating based on zinc or its alloys wherein the metallic coating is itself coated with a zincsulphate-based layer including at least one of the compounds selected from among zincsulphate monohydrate, zincsulphate tetrahydrate and zincsulphate heptahydrate, wherein the zincsulphate-based layer has neither zinc hydroxysulphate nor free water molecules nor free hydroxyl groups, the surface density of sulphur in the zincsulphate-based layer being greater than or equal to 0.5 mg/m.sup.2. A corresponding treatment method is also provided.

A steel substrate is provided, coated on at least one of its faces with a metallic coating based on zinc or its alloys wherein the metallic coating is itself coated with a zincsulphate-based layer including at least one of the compounds selected from among zincsulphate monohydrate, zincsulphate tetrahydrate and zincsulphate heptahydrate, wherein the zincsulphate-based layer has neither zinc hydroxysulphate nor free water molecules nor free hydroxyl groups, the surface density of sulphur in the zincsulphate-based layer being greater than or equal to 0.5 mg/m.sup.2. A corresponding treatment method is also provided.

The present invention addresses the problem of providing a chemical conversion treatment solution that contains zirconium ions and that makes it possible to form a highly corrosion-resistant chemical conversion coating formed with consideration for the environment as well. The present invention provides a chemical conversion treatment solution that contains trivalent chromium ions, zirconium ions, aluminum ions, at least one type of carboxylic acid ions, and at least one type of silicon compound, the chemical conversion treatment solution being free of fluorine ions and fluorine compounds.

The present invention addresses the problem of providing a chemical conversion treatment solution that contains zirconium ions and that makes it possible to form a highly corrosion-resistant chemical conversion coating formed with consideration for the environment as well. The present invention provides a chemical conversion treatment solution that contains trivalent chromium ions, zirconium ions, aluminum ions, at least one type of carboxylic acid ions, and at least one type of silicon compound, the chemical conversion treatment solution being free of fluorine ions and fluorine compounds.