The invention relates to a method for the production and removal of a temporary protective layer for a cathodic coating, particularly for the production of a hardened steel component with an easily paintable surface, wherein a steel sheet made of a hardenable steel alloy is subjected to a preoxidation, wherein said preoxidation forms a FeO layer with a thickness of 100 nm to 1,000 nm and subsequently a melt dip coating is conducted, wherein, during the melt dip coating, a zinc layer is applied having a thickness of 5 to 20 μm, preferably 7 to 14 μm, on each side, wherein the melt dip process and the aluminum content of the zinc bath is adjusted such that, during the melt dip coating, an aluminum content for the barrier layer results of 0.15 g/m.sup.2 to 0.8 g/m.sup.2 and the steel sheet or sheet components made therefrom is subsequently heated to a temperature above the austenitizing temperature and is then cooled at a speed greater than the critical hardening speed in order to cause hardening, wherein oxygen-affine elements are contained in the zinc bath for the melt dip coating in a concentration of 0.10 wt.-% to 15 wt.-% that, during the austenitizing on the surface of the cathodic protective layer, form a thin skin comprised of the oxide of the oxygen-affine elements and said oxide layer is blasted after hardening by irradiation of the sheet component with dry ice particles.

Foam items may be buffed using particles such as particulate sodium bicarbonate in accordance with the present invention. Foam items may be, for example, expanded EVA foam items pre-formed into an intermediate size and shape. A skin layer may be formed during the expansion of the foam item to form an expanded foam item which may be entirely or partially removed by buffing the item using particles projected with selected buffing parameters. The buffing parameters may be varied based upon the thickness of at least a portion of the skin layer and/or the desired degree of moldability for the foam item after buffing. Particulate sodium bicarbonate or other types of particles used for buffing may be recycled and reused for further buffing of foam items.

Methods of cleaning flow path components of power systems, and sump purge kits used in the same or related methods are disclosed. A method of cleaning may include removing a casing of the turbine system to expose a rotor of the turbine system, a plurality of flow path components coupled to the rotor and/or the casing, and a sump system in communication with the rotor. The method may also include pressurizing the sump system in communication with the rotor, and sealing a plurality of openings formed in the rotor. Additionally, the method may include exposing the rotor and the plurality of flow path components to steam to dry hydrocarbons formed on a surface of the rotor and a surface of the plurality of flow path components, and blasting the rotor and the plurality of flow path components with solid carbon dioxide (CO.sub.2) to dislodge the dried hydrocarbons.

An abrasive blasting system has an abrasive container or pot, preferably with a downwardly conically shaped interior bottom surface. A slurry delivery tube is positioned within the pot, with an open bottom end positioned at an operative distance above the bottom of the pot. The slurry delivery tube runs vertically upward and exits the pot, ultimately running to a hose and nozzle. With an abrasive slurry of solid particulate abrasive media and water inside the pot, air pressure is applied within the pot. When a relatively lower pressure is created in the slurry delivery tube, the resulting pressure differential moves the slurry downward within the pot, then upward through the slurry delivery tube, through the hose and ultimately to the nozzle, where it is directed by an operator onto a workpiece. The system is especially useful when using very fine abrasive material.

Provided is a manufacturing method of a grain-oriented electrical steel sheet including preparing a hot-rolled sheet by hot-rolling a slab; removing some of scales formed on the hot-rolled sheet and leaving a scale layer having a thickness of 10 nm or more to prepare a hot-rolled sheet on which the scale layer remains; preparing a cold-rolled sheet by cold-rolling the hot-rolled sheet on which the scale layer remains; preparing the decarburization annealed cold-rolled sheet by decarburization annealing the cold-rolled sheet; coating an annealing separator on the decarburization annealed cold-rolled sheet to form a metal oxide layer; and final annealing the steel sheet on which the metal oxide layer is formed, wherein the annealing separator includes magnesium oxide (MgO) or magnesium hydroxide (MgOH) and fluoride.

Provided is a wet blasting treatment device including a first nozzle unit that discharges, toward a target treatment region of a workpiece, slurry in which a first liquid and abrasive grains are mixed, a second nozzle unit that discharges a second liquid toward an untreated region adjacent to the target treatment region such that a liquid film is formed in the target treatment region of the workpiece, and a control unit that controls a discharge amount of the second liquid discharged by the second nozzle unit such that the liquid film has a predetermined thickness.

A blasting abrasive and a method of use are provided. The blasting abrasive includes a ferrochrome slag having a composition of SiO.sub.2 in a range of from about 30 to 40 wt% (weight percent); Al.sub.2O.sub.3 in a range of from about 25 to 35 wt%; of Fe.sub.2O.sub.3, Cr.sub.2O.sub.3, or a combination thereof in a range of from about 10-20 wt%; MgO in a range of from about 15 to 25 wt%, by weight of the ferrochrome slag. The ferrochrome slag has a particle size in a range of from about 100 to 850 .Math.m (micrometers) with a particular size distribution.

A blast nozzle for a depowdering apparatus includes an abrasive material inlet fluidly connected to an abrasive material outlet and a fluid inlet fluidly connected to a fluid outlet, where the fluid outlet at least partially surrounds the abrasive material outlet. The fluid outlet is angled with respect to the abrasive material outlet and configured to emit a fluid stream directed to a focal point, the focal point being laterally spaced apart from the blast nozzle in a fluid flow direction.

A method for processing a siliceous, hot-rolled steel sheet for producing an electric steel strip, wherein the steel sheet contains more than 1.5% parts by weight of silicon. The method may include conducting a surface treatment in a device for removing oxide layers from a surface of the steel sheet to produce a cleaned steel sheet, and conducting a heat treatment of the cleaned steel sheet after the surface treatment in a hot-rolled strip annealing plant in an inert gas atmosphere. The surface treatment for removing the oxide layers may be carried out mechanically, without chemical descaling. The heat treatment of the cleaned steel sheet is carried out subsequent to the surface treatment.

A manufacturing method of an electrical steel sheet according to an embodiment of the present invention includes: hot-rolling a slab to manufacture a hot-rolled sheet; removing some of scales formed on the hot-rolled sheet and leaving a scale layer having a thickness of 10 nm or more; controlling roughness of the hot-rolled sheet in which the scale layer remains; cold-rolling it to manufacture a cold-rolled sheet; and annealing the cold-rolled sheet.