Vent piece, tire vulcanization mold with vent piece, and tire manufactured using tire vulcanization mold

A method for manufacturing a tire, comprising:

• placing a raw tire in a vulcanization mold comprising a vent piece;
• and
• vulcanizing the raw tire in the tire vulcanization mold such that air trapped between the raw tire and the tire vulcanization mold is discharged through the vent piece,
• wherein the vent piece of the tire vulcanization mold comprises a cylindrical tube configured to be installed in a cavity end portion of a vent channel of the tire vulcanization mold and having a through hole extending in an axial direction of the vent channel, and a plug positioned in the through hole of the cylindrical tube and configured to move in the axial direction between a closed position and an open position, the cylindrical tube has a first bearing surface, the plug has a second bearing surface facing the first bearing surface of the cylindrical tube such that the second bearing surface of the plug makes contact with the first bearing surface to close the vent channel in the closed position and the second bearing surface is separated from the first bearing surface to open the vent channel in the open position, and each of the first bearing surface and the second bearing surface has a plated layer and a film formed on the plated layer at least on a portion of each of the first bearing surface and the second bearing surface such that the film reduces friction between the first bearing surface and the second bearing surface.