The invention relates to a method for continuously roller-forming and hardening sheet steel in which a sheet steel strip is continuously roller-formed into a profile in a roller-profiling unit, characterized in that the roller-formed profile strand is preheated to a temperature below the austenite starting temperature (Ac.sub.1) and the roller-formed profile strand is then heated across subregions of its cross-section and/or subregions of its length to a temperature above AC.sub.3, with the roller-formed profile strand being acted on with tension at least during the heating of subregions to a temperature >AC.sub.3.

A method of making a rare earth magnet containing zero heavy rare earth elements includes a step of mixing the fine grain powder with the lubricant having a weight content of at least 0.03 wt. % and no greater than 0.2 wt. % for a period of between 1 and 2 hours. The step of pulverizing is further defined as jet milling the alloy powder with the lubricant using a carrier gas of argon or nitrogen. The method further includes a step of controlling oxygen content during the steps of melting, forming, disintegrating, mixing, pulverizing, molding, and sintering whereby the impurities including Carbon (C), Oxygen (O), and Nitrogen (N) satisfies 1.2C+0.6O+N≤2800 ppm. A rare earth magnet composition including C, O, and N whereby C, O, and N satisfies 1.2C+0.6O+N≤2800 ppm and has zero heavy rare earth elements.

A cooling method for a workpiece includes placing entirety of the workpiece in an inner space of a recess provided on a molding surface of a lower mold, pressing or restraining the workpiece by a mold including the lower mold and an upper mold in which a protrusion corresponding to the recess of the lower mold is provided on a molding surface, supplying a liquid coolant to the inner space of the recess through a coolant supply passage provided in at least one of the lower mold and the upper mold by a pump, and discharging air in the inner space of the recess upward through an air escape passage, and cooling the workpiece by immersing the entirety of the workpiece, which has been heated, in the liquid coolant that fills the recess.

A cooling method for a workpiece includes placing entirety of the workpiece in an inner space of a recess provided on a molding surface of a lower mold, pressing or restraining the workpiece by a mold including the lower mold and an upper mold in which a protrusion corresponding to the recess of the lower mold is provided on a molding surface, supplying a liquid coolant to the inner space of the recess through a coolant supply passage provided in at least one of the lower mold and the upper mold by a pump, and discharging air in the inner space of the recess upward through an air escape passage, and cooling the workpiece by immersing the entirety of the workpiece, which has been heated, in the liquid coolant that fills the recess.

A method of cooling of a flat metal product having a broad face and a temperature upper to 400° C., wherein the metal product is put in contact with a fluidized bed of solid particles, the solid particles having a direction of circulation (D) and capturing the heat released by the metal product and transferring the captured heat to a transfer medium wherein the metal product is put in contact with the solid particles so that its broad face is parallel to the direction (D) of circulation of the solid particles, a thermal cooling path of the metal product is defined, considering the product parameters of the metal product, a gas is injected for fluidizing the solid particles in a bubbling regime, the injection flow rate of said gas being controlled to match the defined cooling path of the metal product.

Disclosed are implementations for heat treatment of a metal component, and a use of a furnace for heating a metal component. The implementations can be used in the partial hardening of optionally pre-coated components made of a high-strength manganese-boron steel. An example method for heat treatment of a metal component comprises at least the following steps: a) heating the component in a first furnace; b) moving the component into a temperature control station; c) cooling at least one first sub-region of the component in the temperature control station, wherein a temperature difference is set between the at least one first sub-region and at least one second sub-region of the component; d) moving the component from the temperature control station into a second furnace; and e) heating at least the at least one first sub-region of the component in the second furnace by at least 200 K.

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.

Provided is a prehardened steel material containing: 0.05≤C≤0.25 mass %, 0.01≤Si≤1.00 mass %, 0.40≤Mn≤1.80 mass %, 0.0002≤S≤0.3000 mass %, 0.30≤Cu≤1.80 mass %, 2.00≤Ni≤3.90 mass %, 0.05≤Cr≤3.20 mass %, 0.05≤Mo≤0.80 mass %, and 0.30≤Al≤1.50 mass %, with a balance being Fe and unavoidable impurities, in which the prehardened steel material has: a cross-sectional size of 350 mm or more in width and 350 mm or more in height, a hardness of 34 to 43 HRC, an average value of prior austenite grain size being 85 μm or less, and an average value of impact value being 18 J/cm.sup.2 or higher.

A steel material has a chemical composition which consists of, in mass %, C: 0.15 to 0.30%, Si: 0.02 to 1.00%, Mn: 0.20 to 0.80%, P: 0.020% or less, S: 0.028% or less, Cr: 0.80 to 1.50%, Mo: 0.08 to 0.40%, V: 0.10 to 0.40%, Al: 0.005 to 0.060%, N: 0.0150% or less, O: 0.0030% or less, and the balance: Fe and impurities, and satisfies Formulae (1) and (2), in which, at a cross section parallel to the axial direction of the steel material for a steel piston, the number of Mn sulfides is 100.0 per mm.sup.2 or less, the number of coarse Mn sulfides having an equivalent circular diameter of 3.0 μm or more is in a range of 1.0 to 10.0 per mm.sup.2, and the number of oxides is 15.0 per mm.sup.2 or less.

0.42≤Mo+3V≤1.50  (1)

V/Mo≥0.50  (2)