Sumitomo Metal Industries, Inc.

Nippon Steel Sumitomo Metal Corporation

Toshihiro Imoto

Osamu Miyahara

Hiroyuki Anada

Kazuyuki Kitamura

Masanari Kimoto

Mitsuharu Yonemura

Manabu Kanzaki

Shoji Kinomura

A method for heat treating a metal tube or pipe is provided to perform heat treatment in such a manner that metal tubes or pipes () to be accommodated in a heat treatment furnace are laid down on a plurality of cross beams () arranged along a longitudinal direction of the metal tubes or pipes with the distance between adjacent cross beams being in a range of 200 to 2500 mm. This makes it possible to inhibit bending and scratches of the metal tubes or pipes without causing discoloration and deterioration of the manufacturing efficiency for the metal tubes or pipes. When the metal tubes or pipes () are laid down on the cross beams (), spacers may be interposed between the metal tubes or pipes () and the cross beams () on which they are laid down.

Method for heat treating a metal tube or pipe, metal tube or pipe, and heat treatment furnace

A Ni&#x2014;Cr alloy tube demonstrating an excellent corrosion resistance in a high temperature water environment can be provided,

Ni-Cr alloy material

A method of heat treatment for an efficient forming of two-layered oxide film on the inside surface of a Ni-base alloy tube. The oxide film suppresses the Ni release in a high-temperature water environment. At least two gas supplying devices are provided on the outlet side of a continuous heat treatment furnace; or one gas supplying device is provided respectively on the outlet side and the inlet side thereof. The tube is put into the furnace while supplying an atmospheric gas into the tube from the front end of the tube moving direction with one of these gas supplying devices and a gas introducing pipe, which is arranged inside the furnace, and this tube is maintained at 650 to 1200&#xb0; C. for 1 to 1200 minutes. The atmospheric gas consists of hydrogen or a mixture of hydrogen and argon, whose dew point is in a range of from &#x2212;60&#xb0; C. to +20&#xb0; C. After the front end of the Ni-base alloy tube reaches the outlet side of the furnace, the supply of atmospheric gas into the tube is switched to the supply from other gas supplying device. The operations are repeated.

Method of heat treatment for Ni-base alloy tube

Nickel-base alloy product and method of producing the same

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Kobe, Japan

Toshihiro Imoto