Material Creep Testing
Structural Integrity is proud to continue the legacy of quality, specialty, creep testing originally established by Howard Voorhees in 1963.
- Creep deformation and rupture testing of tensile samples up to 2” x 4” in cross section at temperatures up to 1800°F.
- Design and machining of samples from ex-service samples such as pipe segments or welds, with the capability to electron beam weld add-on material to make a complete sample.
- Consulting on design of creep test programs, evaluation of test results, and metallurgical evaluation of creep samples.
Services / Offerings
Specimen Design and Machining
Consulting and engineering services to obtain valid creep samples from non-standard material pieces such as ex-service material (e.g. pipe cross sections) or welds (e.g. from core samples). Such samples often require add-on material for gripping, or careful design to ensure a valid gauge length to obtain meaningful creep data. We have a number of standard approaches for such samples or we can design a valid test using our in-depth metallurgical and engineering capabilities. We can also advise on appropriate test conditions (stress and temperature) and provide estimates on how long tests may last at particular conditions.
Large Feature Tests
Our large capacity creep frames are able to perform so-called “feature tests” that sample large volumes of material, provide appropriate constraint, or include stress concentrating features to more accurately represent conditions in actual components.
We have capability and experience in running Omega creep tests commonly used for remaining life estimation in petrochemical components, per the American Petroleum Institute (API) fitness-for-service standard API 579. Tests can be run under customer-defined conditions or we can advise on appropriate specimen designs and test conditions for particular components.
Creep-rupture tests typically apply a constant load to a test specimen at constant temperature and the creep strain (deformation) of the specimen is measured to obtain a “creep curve” showing how strain is accumulated as a function of time. Typically these tests are continued until the sample fails (ruptures).
Stress-rupture tests are similar to creep rupture tests but do not include creep strain (deformation) measurements. That is, only the time at which the sample fails is recorded.
Creep Data Analysis
Creep deformation and rupture data often require analysis and interpretation to provide remaining life estimates for the components from which samples were extracted, or to create so-called constitutive equations for life prediction. We have extensive experience in analysis and assessment of creep data ranging from statistical evaluations to creation of life prediction models.
In collaboration with our metallurgical laboratory we can provide detailed metallurgical evaluation of material to be tested, or post-test analysis. This includes microstructure evaluation, chemical analysis, and hardness testing.