A treatment device is provided for single-stage treatment of a metal object, wherein the treatment comprises at least pickling and phosphating of the object. The treatment device comprises a treatment container for holding the object to be treated and for holding a flowable treatment substance, and a pumping apparatus for circulating at least a portion of the treatment substance. The treatment substance is flowable around at least part of the object to be treated, and the treatment substance is a phosphorus- or phosphate-containing solution. The phosphorus- or phosphate-containing solution consists of water and a reaction substance, and the reaction substance consists of phosphorus or of a phosphate and at least one additional substance that improves the treatment effect. The fraction of the phosphorous or the phosphate in the reaction substance is between 75 vol % to 94 vol %, and the reaction substance has no fractions of hydrochloric acid and sulfuric acid.

A chromium-free surface-treated metal sheet includes a metal sheet, a surface-treatment coating that contains a polycarboxylic acid type polymer and a zirconium compound and that is formed on at least one surface of the metal sheet, and a coating that contains a polyester resin, a phenol resin and an acid catalyst and that is formed on the surface-treatment coating. The surface-treated metal sheet can be used for producing cans and can lids maintaining excellent dent resistance even for acidic beverages, without permitting the organic resin film formed on the coating to be peeled even under high-temperature and wet environments during a sterilization treatment or the like, and maintaining excellent hot water-resistant adhering property.

An aqueous conversion coating solution comprises a trivalent chromium compound, a zirconate compound, and a dye compound. The trivalent chromium compound can comprise trivalent chromium compounds such as trivalent chromium sulfate. The dye compound can comprise an azo dye, a chromium complex dye, an anthraquinoid dye, and/or a methine dye. The zirconate compound can comprise alkali metal hexafluorozirconate compounds. The conversion coating solution can comprise a phosphorous compound such as an organic amino-phosphonic acid compound. The conversion coating solution can be formed by mixing a dye additive containing the dye with a trivalent chromium conversion coating solution that does not contain a dye. The conversion coating solution can be used to treat metal substrates comprising aluminum, magnesium, and/or zinc.

An aqueous conversion coating solution comprises a trivalent chromium compound, a zirconate compound, and a dye compound. The trivalent chromium compound can comprise trivalent chromium compounds such as trivalent chromium sulfate. The dye compound can comprise an azo dye, a chromium complex dye, an anthraquinoid dye, and/or a methine dye. The zirconate compound can comprise alkali metal hexafluorozirconate compounds. The conversion coating solution can comprise a phosphorous compound such as an organic amino-phosphonic acid compound. The conversion coating solution can be formed by mixing a dye additive containing the dye with a trivalent chromium conversion coating solution that does not contain a dye. The conversion coating solution can be used to treat metal substrates comprising aluminum, magnesium, and/or zinc.

A hot stamp molded body includes: a steel sheet (30); a first plating layer (10) on a first surface (31) of the steel sheet (30); and a second plating layer (20) on a second surface (32) of the steel sheet (30). The first plating layer (10) includes: a first AlFeSi alloy layer (11) on the first surface (31); and a first AlSi alloy layer (12) on the first AlFeSi alloy layer (11). The second plating layer (20) includes: a second AlFeSi alloy layer (21) on the second surface (32); and a second AlSi alloy layer (22) on the second AlFeSi alloy layer (21). A coating weight of the first plating layer (10) is 31 g/m.sup.2 to 60 g/m.sup.2 and a coating weight of the second plating layer (20) is 5 g/m.sup.2 to 29 g/m.sup.2.

Said coating structure is provided with: a chemical conversion layer (11), which is formed by chemical conversion coating so as to cover the surface of an impeller body (10) obtained from a magnesium alloy that contains magnesium as the main component and which has a film thickness within a previously determined range; and a plating layer (12) formed so as to cover the chemical conversion layer (11).

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.

Provided is a grain-oriented electrical steel sheet having an excellent noise property in an actual transformer. Magnetostrictive properties of the grain-oriented electrical steel sheet are set such that the number of acceleration/deceleration points that are present in the magnetostriction velocity level d?/dt in one period of magnetostrictive vibration is 4 and the magnitude of velocity level change between adjacent velocity change points in an acceleration zone or deceleration zone of magnetostrictive vibration is 3.0?10.sup.?4 sec.sup.?1 or less.

Provided is a grain-oriented electrical steel sheet having an excellent noise property in an actual transformer. Magnetostrictive properties of the grain-oriented electrical steel sheet are set such that the number of acceleration/deceleration points that are present in the magnetostriction velocity level d?/dt in one period of magnetostrictive vibration is 4 and the magnitude of velocity level change between adjacent velocity change points in an acceleration zone or deceleration zone of magnetostrictive vibration is 3.0?10.sup.?4 sec.sup.?1 or less.

The present disclosure is to reduce the number of surface defects in a grain-oriented electrical steel sheet. When manufacturing a grain-oriented electrical steel sheet, a steel slab is heated before being subjected to hot rolling. The heating includes a first heating process of heating the steel slab to a temperature of lower than 1300 C., and a second heating process of heating the steel slab to a temperature of 1300 C. or higher, where the time from the end of the first heating process to the start of the second heating process is 20 seconds or longer, the oxygen concentration in the atmosphere in the second heating process is 1.0 vol % or less, and the surface of the steel slab is subjected to water cooling at a cooling rate of 3.0 C./s or higher after the second heating process and before the hot rolling.