Provided are a high-strength hot-dip galvanized steel sheet that has a tensile strength of 1180 MPa or more and excellent ductility, stretch flangeability, bendability and LME resistance and can manufacture parts with high dimensional accuracy, and its manufacturing method. The high-strength steel sheet with a tensile strength of 1180 MPa or more has a chemical composition containing C, Si, Mn, P, S, Al and N, with [% Si], [% Mn], [% P], [% Mo] and [% Cr] satisfying a predetermined relationship and the balance being Fe and inevitable impurities, and a steel microstructure including ferrite, tempered martensite and bainite, and retained austenite, where the diffusible hydrogen amount in the steel sheet is 0.60 mass ppm or less, a thickness of softened surface layer is 5 μm or more and 150 μm or less, and a frequency of coincidence boundary in the steel sheet surface layer after a high-temperature tensile test is 0.45 or less.

A dehydrogenation processing method for a turbine blade of a steam turbine. The method includes a step of heating the turbine blade by suppling heating steam into a casing of the steam turbine after a steam turbine plant is stopped. The heating steam supplied to the casing has a temperature that is higher than steam passing through the turbine blade during operation of the steam turbine plant. The method further includes repeating the process of supplying the heating steam into the casing a multiple of times.

A dehydrogenation processing method for a turbine blade of a steam turbine. The method includes a step of heating the turbine blade by suppling heating steam into a casing of the steam turbine after a steam turbine plant is stopped. The heating steam supplied to the casing has a temperature that is higher than steam passing through the turbine blade during operation of the steam turbine plant. The method further includes repeating the process of supplying the heating steam into the casing a multiple of times.

Disclosed is a method for manufacturing a corrosion-resistant hot-stamping part and a device thereof. The method includes the following steps: blanking a bare steel plate into a required blank shape; heating the blank to above AC3 in an oxygen-free heating furnace to austenite the blank; putting the austenitized blank into a mold to mold a part; and conducting a surface treatment of the part to form a corrosion-resistant coating layer on a surface of the part. The hot-stamping part manufactured using the described method has good surface quality and great corrosion-resistant performance

An R-T-B based permanent magnet includes main phase grains composed of R.sub.2T.sub.14B type compound. R is a rare earth element. T is iron group element(s) essentially including Fe or Fe and Co. B is boron. An average grain size of the main phase grains is 0.8 m or more and 2.8 m or less. The R-T-B based permanent magnet contains at least C and Zr in addition to R, T, and B. B is contained at 0.75 mass % or more and 0.88 mass % or less. Zr is contained at 0.65 mass % or more and 5.00 mass % or less. A formula (1) of 5.0[B]+[C][Zr]5.6 is satisfied, where [B] is a B content represented by atom %, [C] is a C content represented by atom %, and [Zr] is a Zr content represented by atom %.

An R-T-B based permanent magnet includes main phase grains composed of R.sub.2T.sub.14B type compound. R is a rare earth element. T is iron group element(s) essentially including Fe or Fe and Co. B is boron. An average grain size of the main phase grains is 0.8 m or more and 2.8 m or less. The R-T-B based permanent magnet contains at least C and Zr in addition to R, T, and B. B is contained at 0.75 mass % or more and 0.88 mass % or less. Zr is contained at 0.65 mass % or more and 5.00 mass % or less. A formula (1) of 5.0[B]+[C][Zr]5.6 is satisfied, where [B] is a B content represented by atom %, [C] is a C content represented by atom %, and [Zr] is a Zr content represented by atom %.

Various methods are provided to produce welded structures resistant to hydrogen induced cracking (HIC), improve wear resistance, reduce manufacturing steps including pre/post weld treatments, and improving corrosion resistance. Exemplary methods include using exothermic reactive powder mixtures on as-welded hot surface(s) during weld cooling which generate rapid exothermic reaction melting and hydrogen removal which results in reduction of hydrogen, creation of a wear/corrosion prevention or reduction layer, and a reduction of residual stresses effect in the weld initially formed in initial welding. Alternative embodiments can also employ post cooling re-heating and application of one or more alternative methods using exothermic reactive powders.

Various methods are provided to produce welded structures resistant to hydrogen induced cracking (HIC), improve wear resistance, reduce manufacturing steps including pre/post weld treatments, and improving corrosion resistance. Exemplary methods include using exothermic reactive powder mixtures on as-welded hot surface(s) during weld cooling which generate rapid exothermic reaction melting and hydrogen removal which results in reduction of hydrogen, creation of a wear/corrosion prevention or reduction layer, and a reduction of residual stresses effect in the weld initially formed in initial welding. Alternative embodiments can also employ post cooling re-heating and application of one or more alternative methods using exothermic reactive powders.

An R-T-B based permanent magnet includes main phase grains composed of R.sub.2T.sub.14B type compound. R is a rare earth element. T is iron group element(s) essentially including Fe or Fe and Co. B is boron. An average grain size of the main phase grains is 0.8 m to 2.8 m. The R-T-B based permanent magnet contains at least C and Ga in addition to R, T, and B. B is contained at 0.71 mass % to 0.86 mass %. C is contained at 0.13 mass % to 0.34 mass %. Ga is contained at 0.40 mass % to 1.80 mass %. A formula (1) of 0.14[C]/([B]+[C])0.30 is satisfied, where [B] is a B content represented by atom %, and [C] is a C content represented by atom %.

An R-T-B based permanent magnet includes main phase grains composed of R.sub.2T.sub.14B type compound. R is a rare earth element. T is iron group element(s) essentially including Fe or Fe and Co. B is boron. An average grain size of the main phase grains is 0.8 m to 2.8 m. The R-T-B based permanent magnet contains at least C and Ga in addition to R, T, and B. B is contained at 0.71 mass % to 0.86 mass %. C is contained at 0.13 mass % to 0.34 mass %. Ga is contained at 0.40 mass % to 1.80 mass %. A formula (1) of 0.14[C]/([B]+[C])0.30 is satisfied, where [B] is a B content represented by atom %, and [C] is a C content represented by atom %.