HIGH-PRESSURE FUEL INJECTION TUBE HAVING CONNECTION HEAD AND METHOD FOR PRODUCING THE SAME

Problem to be solved To provide a high-pressure fuel injection pipe which prevents generation of a crack of a pocket portion during formation of a head portion, generation of a crack due to cavitation erosion, and occurrence of tensile stress associated with formation of a pocket, and which is robust against, fatigue failure. Solving Means A high-pressure fuel injection pipe which has, in a connection end portion of a thick-walled and small-diametrical steel pipe, a connection head portion comprising a seat face, an annular flange portion, and a cylindrical face continuing into the seat faces wherein the connection head portion is configured such that cylindrical face has contours in a section along the axial direction of the pipe from an end portion of a fillet portion of the annular flange portion toward the seat face formed such that a rear side opening angle ¸ to an axis of the pipe in the section in the axial direction of the pipe satisfies 0° < ¸ ¤ 20°, and furthermore a ratio of the length h of the cylindrical face in the axial direction of the pipe and the length H from a terminal of the connection head portion to an end portion of the fillet portion on the side of the annular flange portion of the cylindrical face satisfies 0.33 ¤ h/H ¤ 0.85.