Lightweight brake disc with maximized heat dissipation performance and manufacturing method thereof
Disclosed is a method for manufacturing a lightweight brake disc with maximized heat dissipation ability. The method includes a first step of mixing gray cast iron and Fe—Cr ferroalloy with each other to produce a mixture, melting and solidifying the mixture to cast an alloy; a second step of heat-treating the alloy cast in the first step to pearlitize a microstructure of the alloy; and a third step of performing nitriding heat treatment of the alloy heat-treated in the second step.
1 . A method for manufacturing a lightweight brake disc having maximized heat dissipation ability, the method comprising:
a first step of mixing gray cast iron and Fe—Cr ferroalloy with each other to produce a mixture, melting and solidifying the mixture to cast an alloy;
a second step of heat-treating the alloy cast in the first step to pearlitize a microstructure of the alloy, wherein the second step is performed:
at a reaction temperature of 900° C. or higher,
under an inert atmosphere as a reaction atmosphere, and
for a reaction time of 8 hours or larger; and
a third step of performing nitriding heat treatment of the alloy heat-treated in the second step.
2 . The method of claim 1 , wherein the first step is performed:
at a reaction temperature of 1,500° C. or higher,
under an inert atmosphere as a reaction atmosphere, and
for a reaction time of 30 minutes or larger.
3 . The method of claim 1 , wherein the gray cast iron is composed of Fe (iron), C (carbon), Si (silicon), Mn (manganese), S (sulfur) and P (phosphorus).
4 . The method of claim 1 , wherein carbon is present in a form of fine flake graphite in a base material of the gray cast iron.
5 . The method of claim 1 , wherein in the Fe—Cr ferroalloy, a content of Cr is at least 60%.
6 . A method for manufacturing a lightweight brake disc having maximized heat dissipation ability, the method comprising:
a first step of mixing gray cast iron and Fe—Cr ferroalloy with each other to produce a mixture, melting and solidifying the mixture to cast an alloy;
a second step of heat-treating the alloy cast in the first step to pearlitize a microstructure of the alloy; and
a third step of performing nitriding heat treatment of the alloy heat-treated in the second step, wherein the third step is performed:
at a reaction temperature of 500° C. or higher, and
for a reaction time of 8 hours or larger.
7 . A method for manufacturing a lightweight brake disc having maximized heat dissipation ability, the method comprising:
a first step of mixing gray cast iron and Fe—Cr ferroalloy with each other to produce a mixture, melting and solidifying the mixture to cast an alloy;
a second step of heat-treating the alloy cast in the first step to pearlitize a microstructure of the alloy; and
a third step of performing nitriding heat treatment of the alloy heat-treated in the second step, wherein the third step is performed under an atmosphere in which N 2 (nitrogen), NH 3 (ammonia) and CO 2 (carbon dioxide) are mixed with each other as a reaction atmosphere.
8 . The method of claim 7 , wherein a flow rate of the reaction atmosphere in the third step is controlled such that N 2 (nitrogen) is 1.5 m 3 /h, NH 3 (ammonia) is 15 m 3 /h, and CO 2 (carbon dioxide) is 0.3 m 3 /h.
9 . A lightweight brake disc having maximized heat dissipation ability, wherein the brake disc is manufactured by the method according to claim 1 , wherein a tensile strength of the brake disc is in a range of 250 to 280 MPa, and a surface hardness of the brake disc is in a range of 240 to 260 HMW.