Daido Tokushuko Kabushiki Kaisha

Seiya Asari

Takao Shimizu

Noriyoshi Yokota

Masaki Tsuchiya

Yoshihisa Kato

Yuko Takeuchi

Isao Tanaka

The multi-layered heat resistant metal tube is disclosed. This tube has excellent anti-coking characteristics and is suitable for use under the conditions where carbon tends to deposit and accumulate thereon due to contacting with hydrocarbons at a high temperature. The tube is made by forming weld-mounted overlaid layer of Cr&mdash;Ni alloy by building-up welding over the inner surface and/or the outer surface of a substrate tube made of a heat resistant metal. The Cr&mdash;Ni alloy comprises 35% by weight or more of Cr and satisfies the relationship: Ni(w%)&gE;0.5Cr(wt %). Building-up welding is preferably carried out by PPW (Plasma Powder Welding) in which the filler metal is supplied in the form of powder.

Multi-layered anti-coking heat resistant metal tube and method for manufacture thereof

A joined tubular body comprises a titanium alloy pipe of which crystal grain is hard to coarsen at the time of welding or hot-extruding, which consists by weight percentage of at least one element selected from 0.01.about.10% of S, 0.01.about.10% of Se and 0.01.about.10% of Te (the total sum does not exceed 10%), one or both of 0.01.about.10% REM and 0.01.about.10% of Ca (the total sum does not exceed 10%), and the above pipe is joined to a titanium alloy pipe consisting of the above elements and also at least one element selected from Al.ltoreq.10%, V.ltoreq.25%, Sn.ltoreq.15%, Co.ltoreq.10%, Cu.ltoreq.10%, Ta.ltoreq.15%, Mn.ltoreq.10%, Hf.ltoreq.10%, W.ltoreq.10%, Si.ltoreq.0.5%, Nb.ltoreq.20%, Zr.ltoreq.10%, Mo.ltoreq.15%, and 0.ltoreq.0.1% (the total sum does not exceed 30%).

Titanium alloy, member made of the titanium alloy and method for

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Nagoya, Japan

Seiya Asari