Method of manufacturing high pressure fuel injection pipes

摘要

This invention is made with a view to remarkably improving the smoothness of the inside surface of the hole of a high pressure fuel injection pipe to be used for Diesel internal combustion engines and to improving the true circularity of the hole shape and the uniformity of the hole diameter and is a method of manufacturing high pressure fuel injection pipe materials characterized by forming a pipe body by cutting and removing an interposed slag layer collected and deposited near the center of a steel bar material in the steel bar direction and then gradually elongating the pipe body to be of desired dimensions by the repetition of an annealing treatment in a non-oxidizing or reducing atmosphere and a drawing and reducing treatment by using both die and plug.