Liquid Penetrant Testing
Detection of surface-breaking defects in non-porous materials. A liquid dye is applied to the surface, drawn into any open discontinuity by capillary action, then made visible by a developer. Effective for detecting cracks, laps, seams, porosity, and laminations on welds, castings, forgings, and machined surfaces of ferrous and non-ferrous metals, ceramics, and plastics.