Accession Number : ADA190252


Title :   Investigation of the Stress Corrosion Cracking Susceptibility of Annealed and Heat Treated Alloy 625 Castings and Forgings in Sea Water


Descriptive Note : Master's thesis


Corporate Author : MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF OCEAN ENGINEERING


Personal Author(s) : Jones, Eric M.


Full Text : http://www.dtic.mil/get-tr-doc/pdf?AD=ADA190252


Report Date : JUN 1987


Pagination or Media Count : 105


Abstract : Alloy 625, the nickel based superalloy commonly called Inconel 625, was investigated for its susceptibility to stress corrosion cracking in sea water using the slow strain rate tensile test method. Four microstructures of the alloy commonly found in end products were investigated. Bimetallic couplings with other metals were simulated with a potentiostat at plus and minus one volt with respect to a saturated standard calomel electrode (SCE). Baseline tests were conducted in air and sea water without applied potential. The response of the alloy to cathodic protection of minus three volt SCE was also investigated on the two most commonly used microstructures, 'as cast' and forged/annealed. The different microstructures developed were characterized with a scanning electron microscope (SEM). The gage lengths, fracture surfaces, and sections of test specimens were also examined with a SEM. The data from the slow strain rate tensile tests were compared with data from standard tensile tests performed on the same processed material.


Descriptors :   *CRACKS , *NICKEL ALLOYS , *CATHODIC PROTECTION , *STRESS CORROSION , *SUPERALLOYS , *CORROSION RESISTANT ALLOYS , TEST AND EVALUATION , METALS , MICROSTRUCTURE , ELECTRON MICROSCOPES , ELECTRONIC SCANNERS , TENSILE PROPERTIES , VULNERABILITY , TEST METHODS , FRACTURE(MECHANICS) , STANDARDIZATION , BIMETALS , SEA WATER , WELDABILITY , COUPLINGS , ELECTROSLAG WELDING.


Subject Categories : PROPERTIES OF METALS AND ALLOYS


Distribution Statement : APPROVED FOR PUBLIC RELEASE