Denso Corporation

Shu Miyashita

Masami Tanaka

Saburo Sugiura

Yoshitaka Nishizawa

Hirofumi Muranaka

Toshihiro Imai

A high-pressure piping part includes a body structure forged in a closed space. The body structure is formed to include a main body portion formed by forward extrusion and side arm portions formed by side extrusion. The main body portion has therein a fiber flow formed along a passage, and the side arm portion has therein a fiber flow formed along the passage. Therefore, the direction in which stress is applied to the passage of the body structure by an internal pressure is approximately perpendicular to the directions of the fiber flows, thereby improving the degree of allowance of the resistance to pressure of the body structure for an injector.

Method for manufacturing high-pressure piping part and structure thereof

The high carbon stainless steel containing more than 0.5 mass % carbon and more than 8 mass % chromium, or the tool steel containing more than 0.5 mass % carbon and more than 0.5 mass % at least one of carbide producing metal elements including chromium, molybdenum, tungsten, vanadium, niobium and titanium is processed by cold-warm working such as forging at a temperature of less than 800 &deg; C. to make more than 10% plastic deformation to an extent that cracks and voids are formed in the crystallized first stage carbide and, further, processed by a Hot Isostatic Pressing treatment so that the cracks and voids may be cured.

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Anjo, Japan

Shu Miyashita