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Liquid Penetrant Testing (PT) Services

Liquid Penetrant Testing reveals surface-breaking defects by applying a colored or fluorescent dye that seeps into cracks and discontinuities.

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What is Liquid Penetrant Testing?

Liquid Penetrant Testing (PT/LPI) is used to detect surface-breaking discontinuities in non-porous materials. A liquid penetrant is applied to the test surface and allowed to dwell, seeping into any surface-breaking defects by capillary action. Excess penetrant is removed, and a developer is applied which draws penetrant from defects back to the surface, creating visible indications.

How PT Works

1

Penetrant enters surface defects by capillary action

2

Excess penetrant removed from surface

3

Developer draws trapped penetrant back to surface

4

Visual or fluorescent inspection reveals indications

Applications of Liquid Penetrant Testing

Surface crack detection on any non-porous material
Weld inspection
Casting and forging inspection
In-service fatigue crack detection
Quality control in manufacturing
Aerospace component inspection

Advantages

  • Works on virtually any non-porous material
  • Simple and inexpensive
  • Portable - can inspect in field
  • High sensitivity (fluorescent method)
  • Can inspect complex shapes
  • Produces visible indications

Limitations

  • Only detects surface-breaking defects
  • Surface preparation is critical
  • Temperature sensitivity
  • Chemical handling requirements
  • Cannot inspect rough or porous surfaces
  • Multiple process steps required

Applicable Standards & Codes

ASTM E165
ASTM E1417
ASME Section V
ISO 3452
EN ISO 3452
AMS 2644

Industries Using PT

Aerospace
Manufacturing
Oil & Gas
Power Generation
Automotive
Marine

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