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Stellite Failure on a P91 HP Valve — Failure Investigation and Modelling of Residual Stresses

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The sequence of the primary welding process and the following secondary processes of machining, and heat treatment has been modelled to predict the residual conditions in a Stellite 6 overlay weld on a P91 steam turbine valve. The different process steps are coupled in order to transfer the residual conditions from preceding processes to the ones following. The integrated model has been used to analyse a premature rupture in the weld zone between P91 and Stellite. An accurate prediction of the stress level in the weld zone is imperative for the assessment of the quality of the component, and this provides a tool for process modification in order to minimize the risk for future breakdown. Both classical time independent and time dependent plasticity models have been used to describe the different material behaviours during the different process steps. The description of the materials is highly temperature dependent. The welding process is modelled by adding material to the calculation domain, while the machining process is modelled by removing material from the calculation domain to redistribute the stress fields. An in-house iso-parametric FEM-code is used for the implementation of the material models and the discretization of the appropriate addition and removal of material. The return mapping algorithm is used for the time discretization of the time independent plasticity model, and a Norton’s power law model is used for the time dependent model. Results from the numerical calculations are presented.

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  1. [1]

    Carslaw H.S., Jaeger J.C.: Conduction of heat in solids, Oxford Science Publications, Oxford, 1959.

  2. [2]

    Olhoff N., Gudmann A.: Noter til Styrkelaere II. Faststofmekanik, DTU, Lyngby, 1998.

  3. [3]

    Hattel J.H.: Control volume based finite difference method numerical modelling of thermomechanical conditions in casting and heat treatment. Ph.d.-thesis, Dept. Manufact. Eng., Techn. Univ. Denmark, 1993.

  4. [4]

    Hattel J.H., Hansen P.N.: A control volume based finite difference method for solving the equilibrium equations in terms of displacements, Applied Mathematical Modelling, 1995, 19, 4, pp. 550–559.

  5. [5]

    Hill R.: The mathematical theory of plasticity, Clarendon press, Oxford, 1991.

  6. [6]

    Tvergaard V.: Plasticity and creep in structural materials, Department of Mechanical Engineering, Technical University of Denmark, Lyngby, 2001.

  7. [7]

    Lubliner J.: Plasticity Theory, The Macmillan Company, 1990.

  8. [8]

    Mendelson A.: Plasticity: Theory and application, The Macmillan Company, 1968.

  9. [9]

    Kachanov L.M.: Fundamentals of the theory of plasticity, Mir publishers, 1974.

  10. [10]

    Thorborg J.: Constitutive modelling in thermomechanical processes, using the control volume method on staggered grid, Ph.d.-thesis, Dept. Manufact. Eng., Techn. Univ. Denmark, 2001.

  11. [11]

    Kleiber M.: Handbook of computational solid mechanics, Springer Verlag, New York, 1998.

  12. [12]

    Sivakumar M.S., Voyiadjis G.Z.: A simple implicit scheme for stress response computation in plasticity models, Computational Mechanics, Springer-Verlag, Madras, India, 1997.

  13. [13]

    Simo J.C.: Computational inelasticity, Springer Verlag, New York, 1997.

  14. [14]

    Liu W.K., Belytschko T., Moran B.: Nonlinear finite elements for continua and structures, J. Wiley & Sons, New York, 2000.

  15. [15]

    Bathe KJ.: Finite element procedures, Prentice-Hall, Inc., New Jersey, 1996.

  16. [16]

    Wilkins M.L.: Calculation of elastic-plastic flow, In Methods of Computational Physics 3, eds. B. Alder et al. Academic Press, New York, 1964.

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Thorborg, J., Hald, J. & Hattel, J. Stellite Failure on a P91 HP Valve — Failure Investigation and Modelling of Residual Stresses. Weld World 50, 40–51 (2006). https://doi.org/10.1007/BF03266514

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IIW-Thesaurus keywords

  • Failure
  • Stress distribution
  • Finite element analysis
  • Computation
  • Mathematical models
  • Strain
  • Creep
  • Heat treatment
  • Temperature
  • Pressure
  • Austenite
  • Martensite
  • Reference lists
  • Stellite
  • Cobalt alloys
  • Residual stresses