| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a fuel injection pipe causing no damage such as a crack during a necessary plastic working stage and increasing inner pressure fatigue strength without making the fuel injection pipe huge. <P>SOLUTION: An inner pipe which has outer diameter smaller than inner diameter of an outer pipe and consists of one of kinds of precipitation hardening type stainless steels, maraging steel, and austenitic stainless steel of thickness 3.0-4 mm is inserted inside of the outer tube which consists of ferritic carbon steel pipe for high pressure pipe having outer diameter 14-16 mm and wall thickness 3.0-4 mm. Then pipe extension work is performed by integral drawing to closely join the outer pipe and the inner pipe to make double pipe. Necessary heat treatment is applied to the inner pipe after predetermined forming work of the double pipe to increase strength of the inner pipe. <P>COPYRIGHT: (C)2007,JPO&INPIT</p> |
