Accession Number : ADA292953

Title :   Comparison of Cathodic Protection Currents on 70/30 Copper-Nickel and Alloy 625 Piping Systems.

Descriptive Note : Final rept.,

Corporate Author : NAVAL SURFACE WARFARE CENTER CARDEROCK DIV BETHESDA MD

Personal Author(s) : Hack, Harvey P. ; Wheatfall, Walter L.

PDF Url : ADA292953

Report Date : MAR 1995

Pagination or Media Count : 25

Abstract : The objective of this study was to determine whether the demand on a cathodic protection system changes when the protected pipe material is changed from copper-nickel to alloy 625. Two piping mockups were designed to simulate a probable geometry for a cathodically protected piping system. Each mockup consisted of a 20-ft (610-cm) length of nominal 2-in.- (5-cm-) diameter piping with a zinc anode for cathodic protection inserted in the discharge end of each. One mockup was made with 70/30 copper-nickel pipe and the other with alloy 625 pipe. Protection currents and potential profiles inside the pipes were measured over a 6-month exposure period in natural seawater flowing at 7 ft/s (210 cm/s). The total protection current and sacrificial anode consumption for alloy 625 pipe were half that for copper-nickel pipe. Thus, replacing copper-nickel pipe with alloy 625 pipe in areas close to cathodically protected heat exchangers or hulls will result in less demand on the cathodic protection system, as opposed to the original copper-nickel piping. jg

Descriptors :   *CATHODIC PROTECTION, *CURRENTS, *PIPING SYSTEMS, *COPPER NICKEL ALLOYS, MODELS, MATERIALS, COMPOSITE MATERIALS, HULLS(MARINE), PROBABILITY, HEAT EXCHANGERS, PROFILES, PROTECTION, GEOMETRY, ZINC, CONSUMPTION, SEA WATER, ANODES.

Subject Categories : Metallurgy and Metallography
      Physical Chemistry
      Marine Engineering
      Pumps, Filters, Pipes, Tubing, Fittings & Vlvs

Distribution Statement : APPROVED FOR PUBLIC RELEASE