Abstract: Disclosed is a chemical conversion coated Al-plated steel sheet which has excellent weather resistance, water resistance and coating film adhesion. Specifically, a chemical conversion coating liquid is applied over and dried on the surface of an Al alloy-plated steel sheet, thereby forming a chemical conversion coating film that has a film thickness of 0.5-10 ?m. The chemical conversion coating liquid contains: a fluorine-containing olefin resin, which contains 7-20% by mass of F atoms and 0.05-5% by mass of hydrophilic functional groups that are selected from among a carboxyl group, a sulfonic acid group and salts of carboxyl group and sulfonic acid group and has a number average molecular weight within the range of 1,000-2,000,000; and an oxygen acid salt, fluoride, hydroxide, organic acid salt, carbonate or peroxygenated salt of a group 4A metal.

Abstract: The present disclosure relates to a chemically treated zinc-based plated steel sheet that is superior in weather resistance, water resistance, blackening resistance and film adhesion. A chemical conversion film having a thickness 0.5-10 ?m is formed by coating and drying a chemical treatment solution on a surface of an aluminum-containing zinc-based alloy plated steel sheet. The chemical treatment solution contains a fluororesin containing 0.05-5% by weight of a hydrophilic functional group selected from the group consisting of a carboxyl group and a sulfonic acid group and 7-20% by weight of a fluorine atom, the fluororesin in which a number-average molecular weight is 1,000-2,000,000, and an oxoate, a fluoride, a hydroxide, an organic salt, a carbonate or a peroxygenated salt of a group 4A metal.

Abstract: Disclosed is a chemical conversion coated Al-plated steel sheet which has excellent weather resistance, water resistance and coating film adhesion. Specifically, a chemical conversion coating liquid is applied over and dried on the surface of an Al alloy-plated steel sheet, thereby forming a chemical conversion coating film that has a film thickness of 0.5-10 ?m. The chemical conversion coating liquid contains: a fluorine-containing olefin resin, which contains 7-20% by mass of F atoms and 0.05-5% by mass of hydrophilic functional groups that are selected from among a carboxyl group, a sulfonic acid group and salts of carboxyl group and sulfonic acid group and has a number average molecular weight within the range of 1,000-2,000,000; and an oxygen acid salt, fluoride, hydroxide, organic acid salt, carbonate or peroxygenated salt of a group 4A metal.

Abstract: A chemically processed steel sheet comprises a steel base coated with an Al—Si alloy plating layer, whose Si content is preferably adjusted to 5–13 mass % as a whole and to 7–80 mass % at a surface, and a converted layer generated on the surface of the plating layer. The converted layer contains both soluble and scarcely-soluble compounds. The soluble compound, such as a manganese oxide or hydroxide, or a valve metal fluoride, is once dissolved into water in an atmosphere and then re-precipitated as scarcely-soluble compounds at defective parts of the converted layer. The scarcely-soluble compounds act as a barrier for corrosion prevention of a base steel. Due to the re-precipitation, i.e., self-repairing faculty, excellent corrosion resistance of the converted layer is still maintained even after defects are introduced therein during plastic deformation of the steel sheet.

Abstract: An Al-coated steel sheet is improved in anti-scratching property during press-working and corrosion-resistance to a stored fuel by direct formation of an alkali-soluble resin film on an Al-coated steel sheet. An alkali-soluble resin, which can be dissolved in an alkali liquid of pH 9.0 or higher, is preferably urethane or acrylic resin with an acid value of 40-90 having a carboxyl group in its molecule. Alkali metal may be substituted for 1-50% hydrogen atom of the carboxyl group. A powdery synthetic resin at a ratio of 1-25 mass % and/or powdery silica at a ratio of 1-30 mass % may be dispersed in the resin film. The resin film is preferably of 0.2-5.0 ?m in thickness. After the Al-coated steel sheet is painted with the resin, it is shaped to upper and lower halves of a fuel tank and washed with an alkali to dissolve off the resin film. The upper and lower halves are welded together and coated with a paint at their external surfaces to fabricate a fuel tank.

Abstract: A chemically processed steel sheet comprises a steel base coated with an Al—Si alloy plating layer, whose Si content is preferably adjusted to 5-13 mass % as a whole and to 7-80 mass % at a surface, and a converted layer generated on the surface of the plating layer. The converted layer contains both soluble and scarcely-soluble compounds. The soluble compound, such as a manganese oxide or hydroxide, or a valve metal fluoride, is once dissolved into water in an atmosphere and then re-precipitated as scarcely-soluble compounds at defective parts of the converted layer. The scarcely-soluble compounds act as a barrier for corrosion prevention of a base steel. Due to the re-precipitation, i.e., self-repairing faculty, excellent corrosion resistance of the converted layer is still maintained even after defects are introduced therein during plastic deformation of the steel sheet.

Abstract: A chemically processed steel sheet comprising a steel base coated with an Al—Si alloy plating layer, whose Si content is preferably adjusted to approximately 5-13 mass % as a whole and to approximately 7-80 mass % at a surface, and a converted layer generated on the surface of the plating layer. The converted layer contains both soluble and scarcely-soluble compounds. The soluble compound such as a manganese oxide or hydroxide or a valve metal fluoride is once dissolved to water in an atmosphere and then re-precipitated as scarcely-soluble compounds at defective parts of the converted layer. The scarcely-soluble compounds act as a barrier for corrosion-prevention of a base steel. Due to the re-precipitation, that is self-repairing faculty, excellent corrosion resistance of the converted layer is still maintained even after defects are introduced therein during plastic deformation of the steel sheet.

Abstract: A new processed steel sheet comprising of a steel base coated with a Zn or its alloy plating layer and a converted layer, which contains both of at least an insoluble or scarcely-soluble metal compound and at least a soluble metal compound. The insoluble or scarcely-soluble compound may be one or more of valve metal oxides or hydroxides, and the soluble compound may be one or more of valve metal fluorides. The converted layer may be also composed of one or more of complex compounds of Mn and Ti. The insoluble or scarcely-soluble compound acts as a barrier for insulation of a steel base from an atmosphere, while the soluble compound exhibits a self-repairing faculty to repair defective parts of the converted layer. Due to the converted layer, the processed steel sheet is remarkably improved in corrosion resistance, without the presence of chromium compounds which would put harmful influences on the environment.

Abstract: A chemically processed steel sheet comprises a steel base coated with an Al-Si alloy plating layer, whose Si content is preferably adjusted to 5-13 mass % as a whole and to 7-80 mass % at a surface, and a converted layer generated on the surface of the plating layer. The converted layer contains both of soluble and scarcely-soluble compounds. The soluble compound such as a manganese oxide or hydroxide or a valve metal fluoride is once dissolved to water in an atmosphere and then re-precipitated as scarcely-soluble compounds at defective parts of the converted layer. The scarcely-soluble compounds act as a barrier for corrosion-prevention of a base steel. Due to the re-precipitation, i.e. self-repairing faculty, excellent corrosion resistance of the converted layer is still maintained even after defects are introduced therein during plastic deformation of the steel sheet.

Abstract: A new processed steel sheet comprises a steel base coated with a Zn or its alloy plating layer and a converted layer, which contains both of at least an insoluble or scarcely-soluble metal compound and at least a soluble metal compound. The insoluble or scarcely-soluble compound may be one ore more of valve metal oxides or hydroxides, and the soluble compound may be one or more of valve metal fluorides. The converted layer may be also composed of one ore more of complex compounds of Mn and Ti. The insoluble or scarcely-soluble compound acts as a barrier for insulation of a steel base from an atmosphere, while the soluble compound exhibits a self-repairing faculty to repair defective parts of the converted layer. Due to the converted layer, the processed steel sheet is remarkably improved in corrosion resistance, without presence of chromium compounds which would put harmful influences on the environment.

Abstract: In a chromating solution comprising a water-soluble chromium compound and a reducing agent and in which hexavalent chromium ions produced by dissolution of the water-soluble chromium compound have been partly reduced with the reducing agent to trivalent chromium ions, an oxycarboxylic acid compound is used as the reducing agent. This chromating solution causes neither gelation nor sedimentation of the solution even when hexavalent chromium ions are reduced to trivalent chromium ions at a reduction percentage of more than 50%. The chromating solution and a chromate film formed on a steel sheet may also contain an organic resin, phosphoric acid or a phosphoric acid compound, or a silica sol.

Abstract: In a chromating solution comprising a water-soluble chromium compound and a reducing agent and in which hexavalent chromium ions produced by dissolution of the water-soluble chromium compound have been partly reduced with the reducing agent to trivalent chromium ions, an oxycarboxylic acid compound is used as the reducing agent.

Abstract: In a chromating solution comprising a water-soluble chromium compound and a reducing agent and in which hexavalent chromium ions produced by dissolution of the water-soluble chromium compound have been partly reduced with the reducing agent to trivalent chromium ions, an oxycarboxylic acid compound is used as the reducing agent. This chromating solution causes neither gelation nor sedimentation of the solution even when hexavalent chromium ions are reduced to trivalent chromium ions at a reduction percentage of more than 50%. The chromating solution and a chromate film formed on a steel sheet may also contain an organic resin, phosphoric acid or a phosphoric acid compound, or a silica sol.