THE PHYSICAL AND MECHANICAL PROPERTIES OF VALVE ALLOYS AND THEIR USE IN COMPONENT LIFE EVALUATION ANALYSES

The generation and application of physical and mechanical property data to the estimation of diesel engine exhaust valve life is described. Finite element analysis methods are considered that take into account the thermal and mechanical stressing of the component in terms of known engine operating parameters. The physical and mechanical property data utilized in these life predictions have been established on nine alloys chosen, on the basis of superior wear and corrosion resistance, from 33 materials originally evaluated. Included in the nine were commercial casts of En52 and NIMONIC 80A to act as reference materials. To enable life predictions to be made using the finite element methods referred to above, thermal expansion and conductivity estimates were made based on the composition of each material. Tensile data was also established on each in the range RT-750 deg C. In addition, low cycle fatigue data, based on a 6 min trapezoidal 0-to-maximum strain cycle, was established for all materials at 550 deg C and for En52 and NIMONIC 80A at 450, 550 and 650 deg C. These data are reported together with estimates of the likely effect of an aggressive environment on the (LCF) properties and hence, on overall valve life. On the basis of the low cycle fatigue, physical and mechanical property data, in conjunction with the finite element analyses of the component, a final selection of alloys was made for the production of exhaust valves for engine trials, the results of which are reported in other papers of the conference.

Media Info

  • Features: References;
  • Pagination: 13p.

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Filing Info

  • Accession Number: 00659767
  • Record Type: Publication
  • Source Agency: Maritime Technical Information Facility
  • Files: TRIS
  • Created Date: Jul 21 1994 12:00AM