Guide to Thermal Fatigue Management

Thermal fatigue is a specific form of fatigue driven by varying metal temperature gradients and ensuing differential thermal expansion. In general, fatigue is a complex metallurgical process that is cycle dependent and in which failure of a component occurs due to repeated or cyclic loading, which creates cyclic stresses. Furthermore, cyclic stresses can result from mechanical loading (applied loading or vibration) or thermal loading (metal temperature gradients). The application of these cyclic stresses produces slip lines in the crystals of a metal that develop into small cracks. These small cracks then propagate, coalesce, and result in an eventual fracture, which usually involves little-to-no gross plastic deformation.