THE INFLUENCE OF FUEL COMPOSITION ON LIVES OF CURRENT VALVE MATERIALS--PARAMETRIC EQUATIONS FOR VALVE LIFE PREDICTION

The corrosion performance of three alloys--Stellite 6, En52 and NIMONIC 80A has been assessed using statistical methods. These alloys have been exposed to simulated diesel engine combustion environments, typical of those expected when the engine burns residual fuel oil. In these studies three vanadium levels (50, 100 and 150 PPM) and three sodium levels (16, 33 and 50 PPM) have been assessed in addition to alloy selection. It is demonstrated that a full statistical analysis of metal loss due to corrosion permits the separate roles of both contaminants to be identified. Corrosion loss data in these simulated residual fuel oils is found to be log- normally distributed. Analysis of variance has permitted the significant factors and interactions within the corrosion process to be identified. This, in turn, has led to the development of a valve life prediction model based on the rate of growth of areas of extreme corrosion. Three life prediction models are described that have been derived, one for each alloy. These acknowledge the importance of vanadium level, vanadium/sodium ratio and temperature in determining valve life, and predict valve failure by guttering processes .

Media Info

  • Features: References;
  • Pagination: 9p.

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Filing Info

  • Accession Number: 00659773
  • Record Type: Publication
  • Source Agency: Maritime Technical Information Facility
  • Files: TRIS
  • Created Date: Jul 21 1994 12:00AM