Hitachi, Ltd.

Hitachi Kyowa Kogyo Co., Ltd.

Yositeru Chiba

Jiro Kuniya

Isao Masaoka

Masato Koshiishi

Katsuyuki Imai

Kikuo Takeshima

Shin Kumagai

Hard facing layers provided on engagement portions of a valve body and engagement portions of a valve box of a valve apparatus, consisting of cobalt-free Ni-base alloys. One of the Ni-base alloys for the hard facing layers comprises not more than 15% Fe and less than 2% W (tungsten), and the other comprises more than 15% Fe. More specifically, one of the cobalt-free Ni-base alloys essentially consists of, by weight, 15 to 20% Cr, 5 to 10% Si, 10 to 15% Fe, less than 2% W, and the balance of Ni and unavoidable impurities, and has a Vickers hardness (Hv) 510 to 630, and the other essentially consists of, by weight, 5 to 15% Cr, 5 to 10% Si, more than 15% and not more than 30% Fe, 1 to 4% W, and the balance of Ni and unavoidable impurities, and has a Vickers hardness (Hv) 400 to 470. The valve apparatus of the invention is suitably installed in a water pipe line which communicates with a nuclear reactor.

Valve having facing layers of co-free Ni-base Alloy

A method for cooling a weld in steel piping during butt welding with cooling of the inside comprises, after joining of pipe ends by a root pass on the inside, cooling the junction being welded by subsequent passes with injection of a liquid medium at room temperature from the center of the pipe against the surrounding wall, in a direction between radial and tangential directions relative to the inner pipe surface. An apparatus for practicing the cooling method comprises a rotatable multi-nozzle assembly having a radius of rotation corresponding to the inside diameter of the pipe and is capable of injecting the cooling medium against the inner surface of the pipe, a duct for conducting the cooling medium to the nozzles, and a pumping device for forcing the cooling medium under pressure into the nozzles.

Method of cooling weld in steel piping and apparatus therefor

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Hitachi, Japan

Yositeru Chiba