Abstract: A surface treatment solution for a plated steel sheet to be hot-pressed comprising a ZnO aqueous dispersion (A) and a water dispersible organic resin (B), wherein the ZnO aqueous dispersion (A) comprises water and ZnO particle size having 50 to 300 nm particles, the water dispersible organic resin (B) has a 5 to 45 mgKOH/g acid value and 5 to 300 nm emulsion particle size, and a mass ratio (WA/WB) of a mass of ZnO particles in the ZnO aqueous dispersion (WA) to a mass of solid content of the water dispersible organic resin (WB) is 30/70 to 95/5.

Abstract: A surface treatment solution excellent in stability during storage forming a coating for treatment excellent in waterproofness, solvent resistance, and adhesion with a plated steel sheet and able to provide a surface treated steel sheet with hot-pressing lubricity, chemical convertability after hot-pressing, corrosion resistance after coating, and spot weldability, that is, a surface treatment solution for a plated steel sheet to be hot-pressed comprising a ZnO aqueous dispersion (A) and a water dispersible organic resin (B), wherein the ZnO aqueous dispersion (A) comprises water and ZnO particle size having 50 to 300 nm particles, the water dispersible organic resin (B) has a 5 to 45 mgKOH/g acid value and 5 to 300 nm emulsion particle size, and a mass ratio (WA/WB) of a mass of ZnO particles in the ZnO aqueous dispersion (WA) to a mass of solid content of the water dispersible organic resin (WB) is 30/70 to 95/5.

Abstract: An aqueous lubricant for metal material plastic working, which can form a lubricating coating having excellent lubricity (moisture absorption resistance) under a high humidity environment, seizure resistance to metal working with high difficulty, and the like, and further has excellent long-term agent stability; a metal material having a lubricating coating formed by the aqueous lubricant on/over a surface of the metal material; and a metal processed article obtained by molding the metal material are provided. The above problem can be solved by using an aqueous lubricant for metal material plastic working in which an aliphatic polycarboxylic acid having 5 to 8 carbon atoms and a solubility in water at 20° C. of 10 g/100 mL or more and an alkaline earth metal compound are blended in water, or an alkaline earth metal salt of the aliphatic polycarboxylic acid is dissolved or dispersed in water.

Abstract: An aqueous treating solution for an Sn-based plated steel sheet, comprising (A) an organic material, (B) a water-soluble chromium compound, (C) a water-dispersible silica, and water, wherein the organic material (A) is at least one member selected from an oxy-acid with the ratio of hydroxyl group/carboxyl group in one molecule being from 3/1 to 10/1, its lactone form and an oxide derivative thereof, the water-soluble chromium compound (B) does not contain hexavalent chromium, and pH is from 0.7 to 6.0.

Abstract: An aqueous treating solution for an Sn-based plated steel sheet, comprising (A) an organic material, (B) a water-soluble chromium compound, (C) a water-dispersible silica, and water, wherein the organic material (A) is at least one member selected from an oxy-acid with the ratio of hydroxyl group/carboxyl group in one molecule being from 3/1 to 10/1, its lactone form and an oxide derivative thereof, the water-soluble chromium compound (B) does not contain hexavalent chromium, and pH is from 0.7 to 6.0.

Abstract: A rustproofing agent for a zinc plated steel sheet is provided which contains (A) a chromium aqueous solution containing an organic substance and (B) an acid metal such as a metal salt of nitric acid or phosphoric acid. All of the chromium in the chromium aqueous solution of component. A is trivalent chromium. It is preferable if the organic substance in component A contains at least one type of oxy acid or oxide thereof. The metal in the acid metal salt of component B is an alkaline earth metal, cobalt, nickel, iron, zirconium, titanium, etc. It is also preferable if (C) a water-dispersible silica is contained as an additional component. The present invention also provides a zinc plated steel sheet, in which at least one side of the surface of a zinc plated steel sheet is coated with the zinc plated steel sheet rustproofing agent and the rustproofing agent dried to form a coating with a dry coating weight of 0.01 to 3 g/m2.