An inhibited mud acid composition, said composition comprising: hydrofluoric acid in solution; an alkanolamine; and a mineral acid selected from a group consisting of: HCl; MEA-HCl and other modified acids, wherein said alkanolamine and hydrofluoric acid are present in a molar ratio of at least 1:1.

A method of manufacturing a martensitic stainless steel pipe includes: preparing a hollow shell, S1; a pickling step, S3-2, in which the hollow shell is immersed in nitrohydrofluoric acid solution at a temperature below 50° C.; after pickling step S3-2, a high-pressure water washing step, S4, in which high-pressure water is injected onto the outer surface of the hollow shell to clean the outer surface of the hollow shell; after high-pressure water washing step S4, a hot-water immersion step, S5, in which the hollow shell is immersed in hot water if necessary; and spraying gas onto the surface of the hollow shell, S6, before a lapse of 15 minutes from completion of high-pressure water washing step S4 or hot-water immersion step S5.

The invention relates to a method for manufacturing strips of stainless steel, comprising hot rolling in an initial process (A) and subsequently cold rolling in a cold rolling line (B). The hot rolling is stopped when the strip thickness has been reduced to a thickness between 2.0 mm and 6.5 mm. The subsequent cold rolling is passed at least one time through said cold rolling line, which comprises in the following order: At least one cold rolling mill (11-13) in the initial part of the line, at least one annealing section (17), a scale breaking step (21), a shot blasting step (23) and at least one pickling section (26, 27) utilizing a mixture of nitric acid HNO.sub.3, hydrofluoric acid HF and optionally sulphuric acid H.sub.2SO.sub.4.

An acid solution preparation device is an acid solution preparation device for preparing an acid solution used for pickling of a steel plate, the device including a sealed tank for storing the acid solution, a gas supply part for supplying an oxygen-containing gas from outside of the sealed tank to the sealed tank, and a purge part for discharging a gas in the sealed tank to the outside.

Provided are a stainless steel sheet with good corrosion resistance, low contact resistance and good press workability without the use of expensive materials such as gold or rare metals, and a method of manufacture the same. A method of manufacturing a stainless steel sheet includes: preparing a slab having a chemical composition including, in mass %: 20 to 26% Cr, up to 0.1% N, up to 2.0% Si, etc. (step S1); performing hot rolling and cold rolling on the slab to produce a rolled steel sheet with a thickness of 50 to 200 μm (step S2); an annealing step in which the rolled steel sheet is annealed and cooled in a gas atmosphere containing nitrogen (step S3); and pickling the rolled steel sheet after the annealing step with a solution containing a non-oxidizing acid (step S4). The stainless steel sheet has an N content of 0.6 to 2.0% by mass.

An inhibited mud acid composition, said composition comprising: hydrofluoric acid in solution; an alkanolamine; and a mineral acid selected from a group consisting of: HCl; MEA-HCl and other modified acids, wherein said alkanolamine and hydrofluoric acid are present in a molar ratio of at least 1:1.

A treatment liquid is a treatment liquid for a semiconductor device, containing a fluorine-containing compound, a corrosion inhibitor, and calcium, in which the mass content ratio of the calcium to the fluorine-containing compound in the treatment liquid is 1.0×10.sup.−10 to 1.0×10.sup.−4.

A pickling facility includes: a pickling tank for storing an acid solution; a conveyance part for continuously conveying a steel plate immersed in the acid solution; a measurement part for measuring at least one parameter which has a correlation with a heat transfer coefficient between the acid solution and a reference surface disposed in the acid solution so as to face the steel plate; and a conveyance speed decision part configured to decide a conveyance speed of the steel plate conveyed by the conveyance part, on the basis of a measurement result of the at least one parameter.

This ferritic stainless steel has a predetermined chemical composition, at least one type of oxides of oxides containing 5 mass % or more of Al and oxides containing 5 mass % or more of Si are present on the surface, and, among the oxides present on the surface, the number of oxides having a diameter D of 0.1 μm or more and 2.0 μm or less is 10 or more per 93 μm.sup.2, the diameter D being represented by D=(Dmax+Dmin)/2 where Dmax is the maximum diameter of the oxide on the surface and Dmin is the minimum diameter of the oxide on the surface.

Provided is a ferritic stainless steel sheet for current collectors for sulfide-based solid-state batteries, which has excellent sulfidation resistance and adhesiveness. The ferritic stainless steel sheet has a component composition containing Cr in an amount of 16% by mass or more, wherein the surface of the ferritic stainless steel sheet has an uneven structure having recessed portions and projecting portions, the average height of the projecting portions is 20 to 50 nm inclusive, the average distance between the projecting portions is 20 to 200 nm inclusive, and the [Cr]/[Fe], i.e., the ratio of the atom concentration of Cr that is present in a form other than the metal form to the atom concentration of Fe that is present in a form other than the metal form, on the surface of the ferritic stainless steel sheet is 1.0 or more.