A surface treatment solution composition for forming an inorganic film, comprising: 10 to 30% by weight of a trivalent chromium compound containing chromium phosphate (A) and chromium nitrate (B) and satisfying a content ratio A/(A+B) of 0.3 to 0.6; 5 to 50% by weight of a silane compound; 0.2 to 3% by weight of a vanadium-based rust-inhibiting and corrosion-resisting agent; 0.5 to 5% by weight of a cobalt-based rust-inhibiting and corrosion-resisting agent; and 12 to 84.3% by weight of water, an alloyed hot-dip galvanized steel sheet surface-treated using the composition, and a method for manufacturing the alloyed hot-dip galvanized steel sheet, are provided, and the surface treatment solution composition containing the trivalent chromium compound has an excellent effect on corrosion resistance, blackening resistance, fuel resistance, weldability, and alkali resistance.

Provided is a water-based lubricating coating agent for a metal material, capable of carrying out a chemical conversion treatment and a lubrication treatment at the same time, which makes it possible to achieve excellent lubricity even in plastic working, press molding, and the like, and at the same time, operability (e.g., process shortening, sludge reduction). The water-based lubricating coating agent having pH of 2.0 to 6.5 for a metal material is obtained by blending: at least one lubricating component other than black-based solid lubricants; and at least one chemical conversion component selected from the group consisting of a phosphoric acid compound, an oxalic acid compound, a molybdic acid compound, a zirconium compound, and a titanium compound, the concentration of the lubricating component is 5 mass % or more in mass ratio to the total solid content mass in the lubricating coating agent, and the concentration of the chemical conversion component is 0.3 to 8 mass % when the total mass of the lubricating coating agent is regarded as 100 mass %.

Provided is a water-based lubricating coating agent for a metal material, capable of carrying out a chemical conversion treatment and a lubrication treatment at the same time, which makes it possible to achieve excellent lubricity even in plastic working, press molding, and the like, and at the same time, operability (e.g., process shortening, sludge reduction). The water-based lubricating coating agent having pH of 2.0 to 6.5 for a metal material is obtained by blending: at least one lubricating component other than black-based solid lubricants; and at least one chemical conversion component selected from the group consisting of a phosphoric acid compound, an oxalic acid compound, a molybdic acid compound, a zirconium compound, and a titanium compound, the concentration of the lubricating component is 5 mass % or more in mass ratio to the total solid content mass in the lubricating coating agent, and the concentration of the chemical conversion component is 0.3 to 8 mass % when the total mass of the lubricating coating agent is regarded as 100 mass %.

Provided is a water-based lubricating coating agent for a metal material, capable of carrying out a chemical conversion treatment and a lubrication treatment at the same time, which makes it possible to achieve excellent lubricity even in plastic working, press molding, and the like, and at the same time, operability (e.g., process shortening, sludge reduction).

The water-based lubricating coating agent having pH of 2.0 to 6.5 for a metal material is obtained by blending: at least one lubricating component other than black-based solid lubricants; and at least one chemical conversion component selected from the group consisting of a phosphoric acid compound, an oxalic acid compound, a molybdic acid compound, a zirconium compound, and a titanium compound, the concentration of the lubricating component is 5 mass % or more in mass ratio to the total solid content mass in the lubricating coating agent, and the concentration of the chemical conversion component is 0.3 to 8 mass % when the total mass of the lubricating coating agent is regarded as 100 mass %.

An insulating coating for an electrical steel sheet is provided that is formed on a surface of a base metal of the electrical steel sheet and that contains a polyvalent metal phosphate of one or more elements selected from Al, Zn, Mg and Ca, and has an enriched layer of a divalent metal at an interface with the surface of the base metal. An enrichment of the divalent metal contained in the enriched layer is 0.01 g/m.sup.2 or more and less than 0.2 g/m.sup.2.

This surface treatment method comprises a rustproofing step, a rinsing step, and a cleaning step. In the rustproofing step, a rustproofing liquid containing orthophosphoric acid and an organic acid is used to perform a rustproofing treatment on the surface of a steel material. In the rinsing step, a treatment liquid containing an oxo acid salt of a transition metal is used to perform a rinsing treatment on the surface of the steel material. In the cleaning step, the surface of the steel material that has undergone the rinsing step is subjected to a cleaning treatment.

This surface treatment method comprises a rustproofing step, a rinsing step, and a cleaning step. In the rustproofing step, a rustproofing liquid containing orthophosphoric acid and an organic acid is used to perform a rustproofing treatment on the surface of a steel material. In the rinsing step, a treatment liquid containing an oxo acid salt of a transition metal is used to perform a rinsing treatment on the surface of the steel material. In the cleaning step, the surface of the steel material that has undergone the rinsing step is subjected to a cleaning treatment.

The purpose of the present invention is to provide a water-soluble finishing agent for a trivalent chromium chemical conversion coating film, which has low insulation, no problems with tightening properties, outstanding gloss and high corrosion resistance, and can obtain a trivalent chromium chemical conversion coating film, especially a black trivalent chromium chemical conversion coating film, having few scratches and flaws. The finishing agent for a trivalent chromium chemical conversion coating film is characterized by containing a trivalent chromium source, a phosphate ion source, a zinc ion source, a chelating agent which can form a complex with trivalent chromium, and a non-ionic water-soluble polymer compound selected from a group comprising poly(vinyl alcohol) and derivatives thereof, poly(vinyl pyrrolidone) and derivatives thereof, poly(alkylene glycol)s and derivatives thereof, and cellulose ethers and derivatives thereof.

The purpose of the present invention is to provide a water-soluble finishing agent for a trivalent chromium chemical conversion coating film, which has low insulation, no problems with tightening properties, outstanding gloss and high corrosion resistance, and can obtain a trivalent chromium chemical conversion coating film, especially a black trivalent chromium chemical conversion coating film, having few scratches and flaws. The finishing agent for a trivalent chromium chemical conversion coating film is characterized by containing a trivalent chromium source, a phosphate ion source, a zinc ion source, a chelating agent which can form a complex with trivalent chromium, and a non-ionic water-soluble polymer compound selected from a group comprising poly(vinyl alcohol) and derivatives thereof, poly(vinyl pyrrolidone) and derivatives thereof, poly(alkylene glycol)s and derivatives thereof, and cellulose ethers and derivatives thereof.

The present invention belongs to the technical field of surface treatment for metal materials, and particularly relates to an environment-friendly water-based treatment agent for improving the phosphatability of high-strength steel. The water-based treatment agent is prepared by dissolving or dispersing a composition in an aqueous medium. The water-based treatment agent specifically consists of: A. a fluoride ion-containing compound; B. a compound selected from metal ion compounds containing Cu, Zn, Mn, Ni or Fe; C. a compound selected from organic acids; and D. a compound selected from surfactant. The water-based treatment agent can be diluted in water at a ratio of 1:0-20 for subsequent use. The treatment agent can enable the surface of a high-strength steel plate to have excellent phosphatability and is mainly applied to high-strength steel surface modification treatment.