Sumitomo Metal Industries, Inc.

Nippon Steel Sumitomo Metal Corporation

Nippon Steel Corporation

Hiroyuki Anada

Tetsuo Yokoyama

Osamu Miyahara

Kiyoko Takeda

Toshihiro Imoto

Kazuyuki Kitamura

Takahiro Osuki

Masatoshi Toyoda

Junichi Higuchi

There is provided a welding material used for welding of SUS310 stainless steel base metal that contains at least one of Nb and V and is excellent in intergranular corrosion resistance, the chemical composition of the welding material consisting, by mass percent, of C: 0.02% or less, Si: 2% or less, Mn: 2% or less, Cr: 26 to 50%, N: 0.15% or less, P: 0.02% or less, S: 0.002% or less, and Ni: a content percentage satisfying [5&#x2264;Ni&#x2264;Cr&#x2212;14], and the balance of Fe and impurities. Also, there is provided a welding joint of an austenitic stainless steel, which consists of the base metal and a weld metal formed by using the welding material.

Welding material and welding joint

A nickel material, which comprises by mass percent, C: 0.003 to 0.20% and one or more elements selected from Ti, Nb, V and Ta: a total content less than 1.0%, the contents of these elements satisfying the relationship specified by the formula of '(12/48) Ti+(12/93) Nb+(12/51) V+(12/181) Ta&#x2014;C&#x2267;0', with the balance being Ni and impurities, does not deteriorate in the mechanical properties and corrosion resistance even when it is used at a high temperature for a long time and/or it is affected by the heat affect on the occasion of welding. Therefore, it can be suitably used as a member for use in various chemical plants including facilities for producing caustic soda, vinyl chloride and so on. Each element symbol in the above formula represents the content by mass percent of the element concerned.

Nickel material for chemical plant

The high-strength Ni-based alloy tube for nuclear power use consists, by mass percent, of C: 0.04% or less, Si: 0.10 to 0.50%, Mn: 0.05 to 0.50%, Ni: 55 to 70%, Cr: more than 26% and not more than 35%, Al: 0.005 to 0.5%, N: 0.02 to 0.10%, and one or more kinds of Ti: 0.01 to 0.5% and Nb: 0.02 to 1.0%, the balance being Fe and impurities. For this alloy tube, the grain size is as fine as grain size No. 6 or higher in JIS G 0551. It is preferable that the high-strength Ni-based alloy tube be manufactured by the process of preparing a Ni-based alloy stock through a remelting process, hot forging, heating to 1000 to 1160&#xb0; C., hot extruding at a working ratio such that an extrusion ratio is 4 or higher, and performing solution annealing and thermal treatment.

High-strength Ni-based alloy tube for nuclear power use and method for manufacturing the same

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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Nishinomiya, Japan

Hiroyuki Anada