Creep Damage
Creep damage is the time-dependent permanent deformation and eventual cracking of materials subjected to constant stress at high temperature (typically above 0.4 of the melting point in Kelvin), occurring in fired heater tubes, reformers, and high-temperature piping.
Definition
Creep damage progresses through micro-void formation, void linking, and macro-crack propagation. It is detected by metallography (replica testing), by surface MT/PT for surface-breaking creep cracks, and by UT for advanced creep cracks. API 579 Part 10 provides creep assessment procedures.
Related terms
- Fatigue Crack — A fatigue crack is a crack that initiates and propagates under cyclic loading at stress levels below the static tensile strength of the material, producing characteristic beach marks visible on the fracture surface.
- Hydrogen Embrittlement — Hydrogen embrittlement is the loss of ductility and load-bearing capacity of a metal caused by the absorption of atomic hydrogen, typically affecting high-strength steels, titanium alloys, and some nickel alloys.
More defect terms
Crack · Lack of Fusion · Lack of Penetration · Slag Inclusion · Porosity · Undercut · Overlap · Burn-Through · Weld Spatter · Lamination
Where this comes up in practice
Terms like this one appear in three places that matter commercially: the written practice that governs how your personnel are qualified, the procedures and technique sheets that define how an examination is actually performed, and the evidence an auditor or client asks for when they want to know why an inspection was accepted. Getting the terminology right is the easy part; being able to produce the qualification record, the calibration traceability and the procedure revision that applied on the day of the inspection is the part that decides audits.
Atlantis NDT provides NDT training and certification against ASNT SNT-TC-1A and ISO 9712, ASNT Level III consulting for written practices and procedure approval, inspection management software that holds qualification, calibration and procedure-revision evidence in recoverable form, and an asset integrity platform that binds inspection results to the asset they describe. Browse the full NDT glossary or ask a Level III directly.