| 摘要 |
PROBLEM TO BE SOLVED: To provide ultra high pressure fuel piping which eliminates non-metallic inclusions on an inner surface without the usage of an expensive material such as clean steel difficult to be secured, is excellent in inner pressure fatigue strength, and has a fuel injection pressure larger than 1,800 atm, and also to provide its manufacturing method. SOLUTION: On an inner surface wherein the non-metallic inclusion exists on a contact surface with fuel and/or just below the contact surface, one of an active metal paste selected from an active metal paste consisting essentially of titanium, an active metal paste consisting essentially of molybdenum-manganese, an active metal paste consisting essentially of chromium, and an active metal paste consisting essentially of boron, is applied to a fatigue strength reinforcement required surface, and then, heat treatment is applied under a high temperature vacuum atmosphere or a high temperature hydrogen atmosphere, the surface of the non-metallic inclusion is metallized by titanium or molybdenum-manganese, and a fatigue strength reinforced layer comprising a diffusion layer by titanium or molybdenum and manganese is generated on a surface of a base material around the non-metallic inclusion. COPYRIGHT: (C)2007,JPO&INPIT
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