A method for producing an alloy steel composition includes the following steps: performing a first heat treatment on an alloy steel composition and maintaining for a first time period to soften the alloy steel composition; performing a first cooling treatment on the softened alloy steel composition; performing a treatment on the softened the alloy steel composition to form a workpiece; performing a second heat treatment on the workpiece and maintaining for a second time period; and performing a second cooling treatment on the workpiece to make the workpiece become to be a Bainite structure, and a cooling rate of the second cooling treatment is high than the cooling rate of the first cooling treatment.

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 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 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 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 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.

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 sliding member (1) includes an iron and steel-based sintered compact containing chromium, molybdenum, and carbon and having a content of chromium, of 5 mass % or less. The sliding member (1) includes: a compound layer (11) which has a sliding surface (1a) and is formed mainly of an iron and steel nitride; and a diffusion layer (12) which is adjacent to the compound layer (11) and has an iron and steel structure into which nitrogen and carbon diffuse. The concentrations of carbon and nitrogen in the diffusion layer (12) are gradually reduced with increasing depth from the sliding surface (1a).

A sliding member (1) includes an iron and steel-based sintered compact containing chromium, molybdenum, and carbon and having a content of chromium, of 5 mass % or less. The sliding member (1) includes: a compound layer (11) which has a sliding surface (1a) and is formed mainly of an iron and steel nitride; and a diffusion layer (12) which is adjacent to the compound layer (11) and has an iron and steel structure into which nitrogen and carbon diffuse. The concentrations of carbon and nitrogen in the diffusion layer (12) are gradually reduced with increasing depth from the sliding surface (1a).

A method for producing an alloy steel composition includes the following steps: performing a first heat treatment on an alloy steel composition and maintaining for a first time period to soften the alloy steel composition; performing a first cooling treatment on the softened alloy steel composition; performing a treatment on the softened the alloy steel composition to form a workpiece; performing a second heat treatment on the workpiece and maintaining for a second time period; and performing a second cooling treatment on the workpiece to make the workpiece become to be a Bainite structure, and a cooling rate of the second cooling treatment is high than the cooling rate of the first cooling treatment.