Valve
AssigneeKabushiki Kaisha Toshiba
InventorsKaoru Tada, Mituo Kawai, Tetsuo Fujiwara, Noriyuki Chujyo, Masahiko Hasunuma, Yuji Yasuda
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Abstract
There is disclosed a valve comprising one valve seat ring, of a disc or a body, having a surface composed of a Cr-Mn-Fe system or a Cr-Ni-Fe system Fe-based precipitation hardening type alloy, and another valve seat ring thereof having a surface composed of a Cr-Ni system Ni-based alloy having a hardness Hv of 400 or more. The valves of this invention can have excellent wear resistance, cavitation erosion resistance and galling resistance, and since emitting no cobalt, the valves of this invention are suitable for various plants such as chemical plants, particularly nuclear power plants.
Claims13
A liquid control valve having mating seating surfaces that are galling-resistant and cavitation erosion-resistant, which comprises a first valve seat ring comprising a disc or a body having a surface consisting essentially of a cobalt-free Fe-based precipitation hardening type alloy selected from the group consisting of Cr-Mn-Fe system and Cr-Ni-Fe system alloys, and a second valve seat ring having a surface different from said first valve seat ring and mating with said first valve seat ring to form a valve closure, said second valve seat ring surface consisting essentially of a cobalt-free Cr-Ni system Ni-based alloy having a hardness Hv of at least about 400.
Dependencies are inferred from the claim text.