A simple, robust and effective parametric model has been developed to provide master curves of creep strain from uniaxial creep testing. The corresponding master curve has been produced for a multicast data set of P91 steel using data from both uninterrupted and interrupted creep tests. The time to specified creep strain at given stress and temperature was fitted in the strain range of 0.1 to 15%. With typical inhomogeneous creep data, the recommended approach involves a four-step procedure: initial investigation of the data quality, heat-specific intermediate modelling of the raw data, extraction of heat-specific stress-temperature-time values for selected evenly spaced range of strain, and re-fitting of these balanced values to the final master curve. The master curve is tested and validated for overall fitting efficiency comparison to other more complex models and to available 1% creep strain and failure predictions. Very competitive fitting efficiency was observed in spite of the simplicity of the model.

Volume Subject Area:
Materials and Fabrication
Topics:
Creep, Modeling, Steel, Fittings, Heat, Stress, Temperature, Failure, Testing
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Copyright © 2006
 by ASME
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