Nippon Steel Sumitomo Metal Corporation

Nippon Steel Corporation

Masatoshi Toyoda

Keishi Matsumoto

Tetsuo Yokoyama

Yoshitaka Nishiyama

Kouichi Kuroda

Takahiro Osuki

Kiyoko Takeda

Masaki Ueyama

Hiroyuki Anada

A method for producing a heat transfer tube for a steam generator comprises a step of providing a tube and then applying cold drawing to the tube by using a high-pressure lubricating oil of 40 MPa or more in pressure. After the step of applying cold drawing to the tube, a step of applying a solid solution heat treatment to the tube is conducted. After the step of applying a solid solution heat treatment to the tube, a step of straightening the tube by using a roll straightening machine is conducted. An offset amount of 5 mm or less is formed for at least successive three pairs of upper and lower straightening rolls of the roll straightening machine.

Method for producing a heat transfer tube for steam generator using drawing, solution heat treatment, and straightening

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

In a drawing method of a metallic tube which includes: filling a high-pressure container with a lubricating oil, the container having a mother tube inserted thereinto; pressurizing the oil with a pressure booster; and drawing the forcedly lubricated mother tube, the oil having a kinetic viscosity of 100 to 2000 mm/s at 40&#xb0; C. and at normal pressure and a viscosity pressure coefficient of 15 to 24 GPaat 40&#xb0; C. is used for preventing seizing and vibrations in drawing and for suppressing the deterioration of surface roughness due to oil pits in tube. Herein, the oil preferably contains one or more of extreme-pressure (EP) additives in a total amount of 10 mass % or more, being selected from a sulfur-based additive, a chlorine-based additive, an organic calcium metallic salt, a phosphorus-based additive, an organic zinc-based additive, and an organic molybdenum-based additive, each having a prescribed amount of relevant element.

Drawing method of metallic tube and producing method of metallic tube using same

A blank tube for cold drawing is used for the production of a longer-length, small-diameter tube such as a heat-transfer tube for steam generation in nuclear power facilities, wherein the blank tube will not cause scoring and chattering vibration in a drawing process. The blank tube is used to produce a cold drawn tube through cold drawing of the blank tube. The average surface roughness Ra (ANSI B46.1) of the inner surface of blank tube before drawing satisfies the condition: 0.10 &#x3bc;m&#x2266;Ra&#x2266;1.00 &#x3bc;m in the case of a blank tube for cold drawing for use in an oil-lubricated drawing. In particular, the surface roughness Ra satisfies the condition: 0.10 &#x3bc;m&#x2266;Ra&#x2266;0.50 &#x3bc;m in the case of a blank tube for use in a high-pressure lubrication drawing and made of an austenitic alloy for use in a heat-transfer tube for a steam generator.

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Tokyo, Japan

Masatoshi Toyoda