Penetraattitarkastus

Penetraattitarkastus, often abbreviated as PT, is a non-destructive testing method used to detect surface-breaking defects in materials. It is particularly effective for identifying cracks, porosity, and other discontinuities that are open to the surface. The process involves applying a liquid penetrant to the surface of the cleaned material. This penetrant is designed to seep into any surface flaws due to capillary action. After a suitable dwell time, excess penetrant is removed from the surface, leaving only the penetrant trapped within the defects.

A developer is then applied to the surface. The developer draws the penetrant out of the defects, creating visible indications. These indications are then examined under good lighting conditions, sometimes with the aid of a black light for fluorescent penetrants. The size, shape, and distribution of these indications help in assessing the nature and severity of the surface discontinuities.

Penetraattitarkastus can be applied to a wide variety of materials, including metals, ceramics, and plastics, provided they are sufficiently porous to prevent excessive absorption of the penetrant. The method is relatively simple and cost-effective, making it a popular choice for many inspection applications. However, it is limited to detecting defects that are open to the surface and cannot reveal subsurface flaws. Various types of penetrants and developers exist, including visible and fluorescent forms, each suited for different applications and inspection environments.