Definition - What does Thermal Fatigue mean?
Thermal fatigue refers to a progressive degradation of a material due to cyclic fluctuations in temperature. Thermal fatigue primarily afflicts metals because they are highly conductive and inherently receptive to temperature changes.
Corrosionpedia explains Thermal Fatigue
A metal object expands when heated and contracts when cooled. As such, repetitive temperature fluctuations ultimately cause wear and tear to the metal's surface. Such metallic components will experience moderate to severe cracking due to the differential thermal expansion. A collection of cracks on a metal's surface propagate structural failure if immediate remediation efforts are not implemented.
Thermal fatigue is also a causative factor for stress corrosion cracking experienced in certain metals and their alloys, which further impacts their structural integrity.
Some testing procedures and practices can be used to inspect for thermal fatigue. Magnetic particle testing (MPT), liquid penetrant testing (LPT) and surface wave ultrasonic testing (SWUT) are the three primary testing processes used to inspect and rectify thermal fatigue in metallic substances.