A grain-oriented electrical steel sheet includes: a steel sheet and optionally an insulation coating formed on the steel sheet, in which, in a case where a heat treatment of performing retention at 800° C. for 2 hours is performed, regarding a time-magnetostriction waveform (t−λ waveform) when magnetized to 1.7 T, a peak value of a difference waveform obtained by subtracting the time-magnetostriction waveform after the heat treatment from the time-magnetostriction waveform before the heat treatment is 0.01×10.sup.−6 or more and 0.20×10.sup.−6 or less, and a difference obtained by subtracting an iron, loss before the heat treatment from an iron loss after the heat treatment is 0.03 W/kg or more and 0.17 W/kg or less.

A method for refining magnetic domains of a grain-oriented electrical steel sheet according to an exemplary embodiment of the present invention includes: a step of preparing a grain-oriented electrical steel sheet; and a step of forming a groove by irradiating a quasi-continuous laser beam of which a duty is from 98.0 to 99.9% on a surface of the grain-oriented electrical steel sheet.

A method for refining magnetic domains of a grain-oriented electrical steel sheet according to an exemplary embodiment of the present invention includes: a step of preparing a grain-oriented electrical steel sheet; and a step of forming a groove by irradiating a quasi-continuous laser beam of which a duty is from 98.0 to 99.9% on a surface of the grain-oriented electrical steel sheet.

A device and method for reducing and homogenizing residual stress of a component by an array of high-energy elastic waves. The device includes a tubular body consisting of at least two elements, multiple first through holes and a clamping device provided on an outer side of the tubular body. Exciters are connected with exciting wedges so that an end face of each of the exciting wedges is closely coupled to a surface of the component. A connection portion is coupled to an emitting end of each of the exciters, where the axis of the emitting end coincides with a normal line at a pressed surface of the component A multi-channel signal amplifier is electrically connected to each of the exciters and a multi-channel excitation control module is electrically connected to the multi-channel signal amplifier.

Provided is a dehydrogenation method capable of efficiently reducing hydrogen content in steel for thick or complexly-shaped steel materials and steel products in general. In a dehydrogenation method for a steel material, in a series of steel material production process including: a process of supplying a steel raw material; a process of subjecting the steel raw material to hot working; a process of inspecting a steel material obtained from the steel raw material; and a process of shipping the steel material, at least one of the steel raw material and the steel material at any stage from the supply process to the shipment process is subjected to, at least once, a sound wave irradiation treatment so that a sound pressure level at a surface of the at least one of the steel raw material and the steel material will be 30 dB or more.

Provided is a dehydrogenation method capable of efficiently reducing hydrogen content in steel for thick or complexly-shaped steel materials and steel products in general. In a dehydrogenation method for a steel material, in a series of steel material production process including: a process of supplying a steel raw material; a process of subjecting the steel raw material to hot working; a process of inspecting a steel material obtained from the steel raw material; and a process of shipping the steel material, at least one of the steel raw material and the steel material at any stage from the supply process to the shipment process is subjected to, at least once, a sound wave irradiation treatment so that a sound pressure level at a surface of the at least one of the steel raw material and the steel material will be 30 dB or more.

A grain-orientation electrical steel sheet according to an exemplary embodiment of the present invention includes a linear groove formed in a direction intersecting with the rolling direction, the groove includes the gradient section and the uniform section on a cross section including the transverse direction of the groove and the rolling surface normal direction of the steel sheet, and a length of the gradient section (GS) and the length of the uniform section (US) satisfy Equation 1 below.

0.1≤[GSL]/[USL]≤0.5  [Equation 1] In Equation 1, [GSL] represents the length (mm) of the gradient section and [USL] represents the length (mm) of the uniform section.

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.

A method for processing corrosion resistant austenitic stainless steel includes: preparing a workpiece made of austenitic stainless steel; and applying compressive residual stress to a surface layer of the workpiece without subjecting the surface layer to plastic working.

A method for processing corrosion resistant austenitic stainless steel includes: preparing a workpiece made of austenitic stainless steel; and applying compressive residual stress to a surface layer of the workpiece without subjecting the surface layer to plastic working.