Dai-ichi High Frequency Co., Ltd.

Nippon Steel Corporation

Flourshing Enterprise Co., Ltd.

Yoichi Matsubara

Hisashi Naoi

Seiichiro Miyata

Yasusuke Inoue

Yoshinobu Sochi

Makoto Kumakawa

Shin-Nan Lee

Akihiro Takeya

Tetsuo Nagasaka

Masaaki Takagishi

Seiichi Akizawa

An alloy-coated boiler part is furnished with a melted coating of alloy material excellent in erosion/corrosion resistance when joined by welding, and free from thermal shock cracking. Super alloy coating () is applied over rapid temperature rise region width (C), where thermal shock cracking may occur at a welding operation, at end portions subjected to weld joint including the vicinity. Self-fluxing alloy coating () is applied on remaining regions other than the rapid temperature rise region width (C). While over a half proportion of each of the alloy coatings () occupied by an Ni-enriched Ni&#x2014;Cr component, the super alloy coating () has the contents of B and Si suppressed to equal or less than 0.1% and equal or less than%, respectively, and in the self-fluxing alloy coating (), the content of each of B and Si is in the range of 1 to 5%.

Alloy-coated boiler part and method of welding self-fluxing alloy-coated boiler part

A clad pipe includes an external layer and a coating layer made of Ni base anticorrosion alloy. Both end portion areas of the coating layer are formed by a build-up welded layer (Ni base alloy of composition) on the inner surface of the external layer. Other areas are formed by a Ni base alloy layer (Ni base alloy of composition) fusion-bonded to the build-up welded layers and the inner surface of the pipe, a solidus-curve temperature of the Ni base alloy layer being 1300&#xb0; C. or below and lower than a solidus-curve temperature of the Ni base alloy formed by build-up welding by 150&#xb0; C. or more. Compositionand compositionare adjusted so that, in the same environment, corrosion resistance of the Ni base alloy of compositionis equivalent to or superior to that of the Ni base alloy of composition

Clad pipe

A bent pipe to which external force, such as an internal pressure and a bending moment, is applied singly or in combination, characterized in that the relationship among the outside diameter D.sub.0 of the bent part, the radius of curvature R of the bent part, the outside diameter D.sub.0 of the straight part, the wall thickness T.sub.0 of the straight part, the central cross section angle .phi. of the bent part and the wall thickness t of the pipe, is in the range defined by the following equations (1) and (2): ##EQU1## whereby the bent pipe has a sectional form of high strength.

Bent pipe having sectional form of high strength

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Kawasaki, Japan

Yoichi Matsubara