(19)
(11) EP 0 169 374 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
26.03.1986 Bulletin 1986/13

(43) Date of publication A2:
29.01.1986 Bulletin 1986/05

(21) Application number: 85107588

(22) Date of filing: 19.06.1985
(84) Designated Contracting States:
DE FR GB IT SE

(30) Priority: 22.06.1984 JP 12763184

(71) Applicant: EBARA CORPORATION
 ()

(72) Inventors:
  • Miyasaka, Matsuho
     ()
  • Ichikawa, Katsuhiro
     ()
  • Sasaki, Katsumi
     ()
  • Mizobuchi, Syotaro
     ()
  • Ogure, Naoaki
     ()

   


(54) Method of preventing stress corrosion cracking in machines or machine parts made of austenitic cast iron


(57) Austenitic cast iron has excellent corrosion resisting properties and has been preferentially used in machines or machine parts intended for handling corrosive fluids such as seawater. Cases, however, have been reported of machines or machine parts made of austenitic cast iron failing after they had been put to prolonged service at relatively low temperatures. The present inventors have located stress corrosion cracking as the cause of this failure. The present invention therefore provides a method of preventing the occurrence of such stress corrosion cracking in machines or machine parts made of austenitic cast iron by subjecting them to cathodic polarization, such cathodic polarization preferably being such that the applied potential is at least 50 mV more base (less noble) than the stabilized natural potential.






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