Gennemtæring

Gennemtæring is a term used in Danish engineering and materials science to describe a through-thickness loss of material, where the degradation progresses from one surface through the entire wall to the opposite side, creating a through-wall defect or perforation. It is a concern in situations where thinning alone is insufficient to judge safety, because a component can no longer contain contents or maintain structural integrity once the full thickness is compromised.

The phenomenon can arise from several mechanisms. Corrosion, including uniform thinning, pitting, and crevice corrosion, can advance until a through-wall opening forms. Mechanical wear, such as erosion or fretting, can also create through-thickness damage, especially in moving-fluid environments or at joints. In some cases, crack initiation and propagation due to fatigue, stress corrosion cracking, or thermal-mechanical stresses lead to a through-thickness breach.

Detection and assessment of gennemtæring rely on non-destructive testing and thickness monitoring. Ultrasonic testing, radiography, and phased-array methods are commonly used to map wall loss and locate through-thickness defects. Complementary techniques include eddy current testing for surface and near-surface damage and infrared thermography for certain hidden defects. Structural integrity analyses may combine measured thickness profiles with material properties and loading to evaluate remaining safety margins.

Prevention and mitigation focus on design and maintenance strategies. This includes selecting corrosion-resistant materials, applying protective coatings, employing cathodic protection, minimizing crevices and stress concentrators, controlling operational environments, and implementing regular inspections and thickness surveillance to detect gennemtæring before it leads to failure.

See also: corrosion, wear, erosion, fatigue crack growth, non-destructive testing.