A method for producing a surface-hardened material, comprising: an immersion step of immersing an iron steel material having nitrogen attached in the form of a solid solution on the surface thereof in a melt containing a chloride at a temperature ranging from 650 C. to 900 C.; and a cooling step of cooling the immersed iron steel material to a temperature equal to or lower than a martensitic transformation start temperature at a cooling rate equal to or higher than a lower critical cooling rare at which martensitic transformation starts.

A method of modifying a grain structure of a metal article includes disposing at least a portion of a metal article in a molten salt bath in a pressure vessel. The molten salt bath has bath temperature that is below a melting point temperature of the metal article. The method also includes pressuring the molten salt bath in the pressure vessel to a forging pressure sufficient to cause pressure-driven grain changes in the metal article.

A method of modifying a grain structure of a metal article includes disposing at least a portion of a metal article in a molten salt bath in a pressure vessel. The molten salt bath has bath temperature that is below a melting point temperature of the metal article. The method also includes pressuring the molten salt bath in the pressure vessel to a forging pressure sufficient to cause pressure-driven grain changes in the metal article.

A method of manufacturing a cam piece for a continuously variable valve duration and a cam piece manufactured therefrom, and more particularly, to material and heat treatment conditions of a cam piece, may include manufacturing a cam piece by casting; heating the cam piece; maintaining a heating temperature; and salt-bathing the cam piece, in which the cam piece includes 3.2 to 4.2 wt % of carbon (C), 2.2 to 3.4 wt % of silicon (Si), and the balance iron (Fe), and may have a carbon equivalent value of 4.4 to 4.6.

A method of treatment of a running ferrous alloy sheet containing at least one easily oxidized element is provided. The method includes a step of immersion of the sheet in a molten oxides bath. The molten oxides bath has a viscosity between 0.3.10.sup.3 Pa.Math.s and 3.10.sup.1 Pa.Math.s, the surface of the bath is contact with a non-oxidizing atmosphere, and the molten oxides are inert towards iron. The residence time of the running sheet in the bath is at least 1 s and the residues of oxides remaining on the surfaces of the sheet at the exit of the bath are eliminated. A treatment line of a ferrous alloy sheet for implementing the method, is provided. The treatment line includes a molten oxides bath having a viscosity between 0.3.10.sup.3 and 3.10.sup.1 Pa.Math.s. The surface of the bath is contact with a non-oxidizing atmosphere, and the molten oxides are inert towards iron. Mechanical devices for eliminating the residues of molten oxides remaining on the surfaces of the ferrous alloy sheet are at the exit of the molten oxides bath.

A method of treatment of a running ferrous alloy sheet containing at least one easily oxidized element is provided. The method includes a step of immersion of the sheet in a molten oxides bath. The molten oxides bath has a viscosity between 0.3.10.sup.3 Pa.Math.s and 3.10.sup.1 Pa.Math.s, the surface of the bath is contact with a non-oxidizing atmosphere, and the molten oxides are inert towards iron. The residence time of the running sheet in the bath is at least 1 s and the residues of oxides remaining on the surfaces of the sheet at the exit of the bath are eliminated. A treatment line of a ferrous alloy sheet for implementing the method, is provided. The treatment line includes a molten oxides bath having a viscosity between 0.3.10.sup.3 and 3.10.sup.1 Pa.Math.s. The surface of the bath is contact with a non-oxidizing atmosphere, and the molten oxides are inert towards iron. Mechanical devices for eliminating the residues of molten oxides remaining on the surfaces of the ferrous alloy sheet are at the exit of the molten oxides bath.

The present disclosure provides a metal back plate and a manufacturing process thereof, a backlight module and an electronic device. The metal back plate is used for the backlight module. The metal back plate includes a first area and a second area. The grain size of the metal material in the first area is larger than the grain size of the metal material in the second area. The first area is formed with a first opening.

A thermal treatment process of a ferrous alloy sheet is provided. The process includes the step of performing a thermal treatment on said sheet when running, by immersing it into at least one molten oxides bath. The molten oxides bath has a viscosity lower than 3.Math.10.sup.1 Pa.Math.s, the surface of the bath is in contact with a non-oxidizing atmosphere and the molten oxides are inert towards iron. The difference between the temperature of the ferrous alloy sheet at the entry of the bath and the temperature of the bath is between 25 C. and 900 C. The residues of oxides remaining on the surfaces of the ferrous alloy sheet at the exit of the bath are eliminated. A device for implementing this process is also provided.

A thermal treatment process of a ferrous alloy sheet is provided. The process includes the step of performing a thermal treatment on said sheet when running, by immersing it into at least one molten oxides bath. The molten oxides bath has a viscosity lower than 3.Math.10.sup.1 Pa.Math.s, the surface of the bath is in contact with a non-oxidizing atmosphere and the molten oxides are inert towards iron. The difference between the temperature of the ferrous alloy sheet at the entry of the bath and the temperature of the bath is between 25 C. and 900 C. The residues of oxides remaining on the surfaces of the ferrous alloy sheet at the exit of the bath are eliminated. A device for implementing this process is also provided.

The present invention provides a steel wire rod with stable workability. The steel wire rod has steel components containing, by mass %, C: 0.20 to 0.60%, Si: 0.15 to 0.30%, Mn: 0.25 to 0.60%, P: 0.020%, S: 0.010%, and a balance of Fe and unavoidable impurities, and an internal microstructure including cementite, in which by number ratio, 80% or more of the cementite in a cross-section vertical to a longitudinal direction of the wire rod has a short axis of 0.1 m or less and a ratio of a long axis to the short axis, defined as an aspect ratio, of 2.0 or less.