▎ 摘　　要

NOVELTY - Bismuth-manganese-iron alloy cored wire comprises a core and a sheath. The sheath comprises a reflecting layer for warning and a radiating layer for radiating heat. The reflecting layer is provided with a reflecting material comprising a protective layer, a reflecting layer and a bottom layer. The protective layer comprises a resin material. The thickness of the protective layer is 1 mm. The reflecting layer is provided with a micro-prism for reflecting. The lower surface of the reflecting layer is attached with a polybutyl acrylate of reflecting material. The lower surface of the protective layer is connected with the upper surface of the reflecting layer by glue. The lower surface of the reflecting layer is connected with the upper surface of the bottom layer by glue. USE - As bismuth-manganese-iron alloy cored wire. ADVANTAGE - The bismuth-manganese-iron alloy cored wire reduces the reaction degree of adding bismuth to molten steel and reduces the cost of adding bismuth. DETAILED DESCRIPTION - Bismuth-manganese-iron alloy cored wire, comprises a core and a sheath. The sheath comprises a reflecting layer for warning and a radiating layer for radiating heat. The reflecting layer is provided with a reflecting material comprising a protective layer, a reflecting layer and a bottom layer. The protective layer comprises a resin material. The thickness of the protective layer is 1 mm. The reflecting layer is provided with a micro-prism for reflecting. The lower surface of the reflecting layer is attached with a polybutyl acrylate of reflecting material. The lower surface of the protective layer is connected with the upper surface of the reflecting layer by glue. The lower surface of the reflecting layer is connected with the upper surface of the bottom layer by glue. The front brightness of the micro-prism is greater 600 cd/lx/m. The bottom layer is made of flexible rubber. The radiating layer is set below the reflecting layer. The radiating layer adopts graphene film. The thickness of the graphene film is 20 m. INDEPENDENT CLAIMS are included for the following: (1) a method for preparing the bismuth-manganese-iron alloy cored wire; and (2) a method for preparing graphene film for radiating bismuth-manganese-iron alloy cored wire.