With the penetrant test in accordance with DIN EN 571-1, fine surface cracks and porosities in weld seams can be made visible.
After cleaning the surface to be inspected, a contrast agent (red or fluorescent) is sprayed on.
Through the capillary effect, this agent penetrates any surface defects there might be.
After re-cleaning the surface, a developer (white) is then sprayed on, which extracts the contrast agent (from any hairline cracks, etc.) and through color contrast, enables an easy evaluation of the defects.
After passing a liquid penetration test, the thermowell is marked with “PT”.