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.

A hot press member includes excellent indentation peel strength which has a tensile strength of 1780 MPa or more. A plating layer has at a surface thereof a 10-point average roughness Rzjis of 25 μm or less, and a steel sheet contains, in mass %, not less than 0.25% but less than 0.50% of C, 1.5% or less of Si, 1.1-2.4% of Mn, 0.05% or less of P, 0.005% or less of S, 0.01-0.50% of Al, 0.010% or less of N, 0.001-0.020% of Sb, 0.005-0.15% of Nb, and 0.005-0.15% of Ti, the balance being Fe and incidental impurities. The average crystal grain size of prior austenite is 7 μm or less and the volume proportion of martensite is 90% or more, within 50 μm in the thickness direction from the surface of the steel sheet excluding the plating layer.

The present invention has as its object the provision of a steel member and steel sheet having high tensile strength and toughness and excellent in hydrogen embrittlement resistance in a corrosive environment and methods for manufacturing the same. The steel member of the present invention has predetermined chemical constituents and has a maximum value of content of Cu in a range from the surface to a depth of 0 to 30 μm of 1.4 times the content of Cu at a depth of 200 μm.

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.

A non oriented electrical steel sheet consists of a silicon steel sheet and an insulation coating. The silicon steel sheet contains Si, Al, and Mn as chemical composition, and an alignment degree to {5 5 7}<7 14 5> orientation in a central area along a thickness direction of the silicon steel sheet is 12 to 35.

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.

A new and improved method for producing electrical steel sheet enabling production of electrical steel sheet excellent in magnetic characteristics and coating film adhesion, the method for producing electrical steel sheet containing a process of bringing an electrical steel sheet containing, by mass %, C: more than 0% and 0.10% or less, Si: 2.5% or more and 4.5% or less, Mn: 0.01% or more and 5.0% or less, a total of one or more of S, Se, and Te: more than 0% and 0.050% or less, acid soluble Al: more than 0% and 5.0% or less, N: more than 0% and 0.015% or less, and P: more than 0% and 1.0% or less and having a balance of Fe and impurities into contact with a solution, the solution containing one or more elements from among Cu, Hg, Ag, Pb, Cd, Co, Zn, and Ni, a total of concentrations of the elements being 0.00001% or more and 1.0000% or less.

A method for producing a grain oriented electrical steel sheet includes a decarburization annealing process where an oxidation degree PH.sub.2O/PH.sub.2 is controlled, an annealing separator applying process where a mass ratio of MgO and Al.sub.2O.sub.3 in an annealing separator is controlled, a final annealing process where an oxidation degree is controlled when atmosphere includes hydrogen or a dew point is controlled when atmosphere consists of inert gas, and an insulation coating forming process where a baking temperature and a heat treatment temperature are controlled.

The present invention has as its object the provision of a coated steel member and coated steel sheet excellent in hydrogen embrittlement resistance in a corrosive environment and methods for manufacturing the same. The coated steel member of the present invention is provided on its surface with an Al-Fe-based coating containing Cu and one or more of Mo, Ni, Mn, and Cr in a total by mass % of 0.12% or more by heating, cooling, and manufacturing a coated steel sheet having a layer containing Cu on its surface under predetermined conditions.

To prevent over-pickling during pickling pause, shorten the time required to switch between pickling operation and pickling pause, and heat acid solution efficiently, a pickling device includes: a pickling tank for storing acid solution and for pickling a steel strip by allowing the steel strip to travel therethrough while the steel strip is immersed in the acid solution; a heat exchanger for heating the acid solution in the pickling tank; a circulation tank for storing the acid solution, provided separately from the pickling tank; an acid-solution circulation device configured to circulate the acid solution between the pickling tank and the circulation tank; a control device configured to withdraw the steel strip from the acid solution; and a guide plate disposed in the pickling tank and configured to guide the acid solution circulated in the pickling tank by the acid-solution circulation device to the heat exchanger.