Provided is a rolling die that increases the durability of a nitrided molded surface. The rolling die (1) includes a tool base material that is made of steel and has a molded surface (2) on which a plurality of working teeth (10) is formed. The tool base material includes a nitride layer (15) in which nitrogen is diffused. The nitride layer (15) is disposed to reach a position that is 20 to 70 ?m in depth from the molded surface (2). The molded surface (2) has a surface hardness of at least 1100 HV. The rate of depth change from the depth (D1) of the nitride layer (15) at crests (11) of the working teeth (10) to the depth (D2) of the nitride layer (15) at roots (13) of the working teeth (10) is not higher than 30%.

Threaded parts such as bolts are rust-proofed by using a treatment liquid including a binder resin containing silica and at least one of a modified epoxy resin obtained by graft polymerization using a carboxylic acid-containing acrylic polymer as a side chain and a modified acrylic resin obtained by graft polymerization using a carboxylic acid-containing acrylic polymer as a side chain. By using this treatment liquid, coating treatment can be carried out at one time without need to use an organic solvent. There is an advantage that the friction coefficient does not increase even when tightening is repeated.

Compositions and methods for preventing corrosion of equipment having a corrodible metal surface that contacts water in a hydrostatic system are provided. Compositions may include a liquid-phase corrosion inhibitor and vapor-phase corrosion inhibitor. Methods may include introducing into the hydrostatic system a liquid-phase corrosion inhibitor, vapor-phase corrosion inhibitor and/or a scaling inhibitor. A protective film can be formed on the corrodible metal surface.

Compositions and methods for preventing corrosion of equipment having a corrodible metal surface that contacts water in a hydrostatic system are provided. Compositions may include a liquid-phase corrosion inhibitor and vapor-phase corrosion inhibitor. Methods may include introducing into the hydrostatic system a liquid-phase corrosion inhibitor, vapor-phase corrosion inhibitor and/or a scaling inhibitor. A protective film can be formed on the corrodible metal surface.

An inorganic coating solution composition including an alkali metal silicate, a curing agent, a dispersant, a defoamer, and a solvent, wherein the curing agent is phosphoric acid (H.sub.2PO.sub.4), the dispersant is at least one selected from among Tween 20, Tween 40, Tween 60, Tween 80, polyvinyl pyrrolidone, polyethylene glycol 400 and polyvinyl alcohol, and the defoamer is at least one selected from among a silicone-based defoamer, an alcohol-based defoamer, a mineral oil-based defoamer and a powder defoamer.

A treatment device is provided for treating a metal object, wherein the treatment comprises at least pickling and phosphating of the object, and, by means of the phosphating, a protective layer is produced on a surface 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 is a phosphorus- or phosphate-containing solution. The 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 treatment effect. The fraction of the phosphorus or the phosphate in the reaction substance is more than 98 vol % and especially preferably more than 99 vol %.

A treatment device is provided for treating a metal object, wherein the treatment comprises at least pickling and phosphating of the object, and, by means of the phosphating, a protective layer is produced on a surface 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 is a phosphorus- or phosphate-containing solution. The 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 treatment effect. The fraction of the phosphorus or the phosphate in the reaction substance is more than 98 vol % and especially preferably more than 99 vol %.

A method of producing a hot-dip Zn alloy-plated steel sheet includes: dipping a base steel sheet in a hot-dip Zn alloy plating bath to form a hot-dip Zn alloy plating layer on a surface of the base steel sheet; and contacting an aqueous solution containing a water-soluble corrosion inhibitor with a surface of the hot-dip Zn alloy plating layer to cool the base steel sheet and the hot-dip Zn alloy plating layer having a raised temperature through formation of the hot-dip Zn alloy plating layer. A temperature of the surface of the hot-dip Zn alloy plating layer when the aqueous solution is to be contacted with the surface of the hot-dip Zn alloy plating layer is equal to or more than 100 C. and equal to or less than a solidifying point of the plating layer. The aqueous solution containing the water-soluble corrosion inhibitor satisfies the Equation [{(Z.sub.0Z.sub.1)/Z.sub.0}10020].

A method of producing a hot-dip Zn alloy-plated steel sheet includes: dipping a base steel sheet in a hot-dip Zn alloy plating bath to form a hot-dip Zn alloy plating layer on a surface of the base steel sheet; and contacting an aqueous solution containing a water-soluble corrosion inhibitor with a surface of the hot-dip Zn alloy plating layer to cool the base steel sheet and the hot-dip Zn alloy plating layer having a raised temperature through formation of the hot-dip Zn alloy plating layer. A temperature of the surface of the hot-dip Zn alloy plating layer when the aqueous solution is to be contacted with the surface of the hot-dip Zn alloy plating layer is equal to or more than 100 C. and equal to or less than a solidifying point of the plating layer. The aqueous solution containing the water-soluble corrosion inhibitor satisfies the Equation [{(Z.sub.0Z.sub.1)/Z.sub.0}10020].

An inorganic coating solution composition including an alkali metal silicate, a curing agent, a dispersant, a defoamer, and a solvent, wherein the curing agent is phosphoric acid (H.sub.2PO.sub.4), the dispersant is at least one selected from among Tween 20, Tween 40, Tween 60, Tween 80, polyvinyl pyrrolidone, polyethylene glycol 400 and polyvinyl alcohol, and the defoamer is at least one selected from among a silicone-based defoamer, an alcohol-based defoamer, a mineral oil-based defoamer and a powder defoamer.