Steel sheet used to manufacture pipe and having corrosion-resistant properties against fuel vapors, and pipe and fuel supply pipe that use same

Abstract

Provided is a steel sheet for manufacturing a pipe having corrosion resistance against fuel vapor of fuel such as gasoline, light oil, bioethanol or bio-diesel fuel, and a pipe and a fuel supply pipe. In the steel sheet for manufacturing a pipe, a Fe—Ni diffusion layer and a softened Ni layer which is provided on the Fe—Ni diffusion layer are formed on a surface of a steel sheet, and a thickness of the softened Ni layer is set to a value which falls within a range of 0.9 to 8.1 μm thus having corrosion resistance against fuel vapor. In the pipe and the fuel supply pipe, a Fe—Ni diffusion layer and a softened Ni layer which is provided on the Fe—Ni diffusion layer are formed on an inner surface of a pipe formed of a steel sheet, and a thickness of the softened Ni layer is set to a value which falls within a range of 0.9 to 8.1 μm. In a fuel supply pipefor supplying fuel to a fuel tank, the fuel supply pipe includes: a large-diameter pipe portionthrough which the fuel passes; and a small-diameter pipe portionwhich makes an upper portion of the large-diameter pipe portion and a lower portion of the large-diameter pipe portion communicate with each other for ventilation, and a Fe—Ni diffusion layer and a softened Ni layer which is provided on the Fe—Ni diffusion layer are formed on an inner surface of at least the small-diameter pipe portion, and a thickness of the softened Ni layer is set to a value which falls within a range of 0.9 to 8.1 μm.