Daido Tokushuko Kabushiki Kaisha

Nippon Kokan Co., Ltd.

Yuko Takeuchi

Hitoshi Hayakawa

Masaki Tsuchiya

Yoshihisa Kato

Takao Shimizu

Kiyoshi Morii

Kazuto Terai

Motoaki Oyama

Seiya Asari

Noriyoshi Yokota

F X Terwijn

Naoki Nishimura

Isao Tanaka

Minoru Yuzuki

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 metal pipe inner surface weld-mounting apparatus having a monitoring device is constituted by an arm, a horizontal torch, a mirror, a camera and a monitoring device. The arm has a supported base end portion, which is horizontally extended. The horizontal torch is attached to a leading end portion of the arm. The weld-mounting is performed on an inner surface portion of a metal pipe supported rotatably around a horizontally extending axis while at least one of the metal pipe and the horizontal torch is moved in a direction of the axis. The mirror is attached to the leading end portion of the arm. The camera is disposed in a position separated from the mirror for picking up an image of weld-mounting beads in a neighborhood of arc light of the horizontal torch through the mirror. The monitoring device monitors a condition of the weld-mounting.

Internal metal pipe welding apparatus and monitoring system

A 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 a Cr&mdash;Ni&mdash;Mo 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&mdash;Mo alloy consists essentially of, by weight %, Cr: 36-49 wt %, Ni: 35-63 wt % and Mo: 0.5-5 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 resisting metal tube and the method for manufacturing thereof

In a method of the present invention for manufacturing a welded clad steel tube, an alloy including a corrosion-resisting or heat-resisting alloy is overlaid on a raw steel tube to manufacture a cold steel tube. Then, a cold or warm working is subjected to the clad steel tube. The clad steel tube is subjected to a heat treatment at a temperature exceeding a recrystallization temperature of the alloy.

Method for manufacturing welded clad steel tube

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Nagoya, Japan

Yuko Takeuchi