Penetrant Testing
Surface flaw detection using liquid penetrants — ideal for non-porous metals and weldments.
Overview
Penetrant Testing (PT), also known as Liquid Penetrant Inspection (LPI), is one of the most sensitive surface inspection methods available. It reveals discontinuities open to the surface on virtually any non-porous material — ferrous, non-ferrous, ceramics, and many plastics — making it indispensable for weld toes, castings, and machined components.
How the method works
A coloured or fluorescent penetrant is applied to a clean surface and drawn into surface-breaking defects by capillary action. After a controlled dwell, excess penetrant is removed and a developer pulls the trapped liquid back to the surface, forming a clearly visible indication.
PT excels at detecting tight, fine cracks that visual inspection alone cannot see — fatigue cracks, stress corrosion cracks, grinding cracks, and porosity. Fluorescent variants under UV-A inspection conditions push sensitivity even further for critical components.
Because PT requires no electrical power and minimal equipment, it is the method of choice for remote sites, offshore platforms, and shutdown environments where other techniques are impractical.
Why AUTRESONUS for PT
- Certified Level II PT technicians experienced in both visible-dye and fluorescent systems.
- Strict adherence to consumable compatibility — critical for stainless and nickel alloys where halogen/sulphur limits apply.
- Photographic indication mapping included in every report for full traceability.
- Combined PT + MT + VT campaigns to deliver complete surface coverage in a single mobilisation.
- 29+ years of field expertise across pipelines, refineries, and offshore assets.
Key Benefits
- Detects extremely fine surface cracks (down to micrometre widths)
- Suitable for ferrous, non-ferrous, and non-magnetic alloys
- Cost-effective with rapid turnaround on large surface areas
- Highly portable — perfect for field and remote inspections
- Compliant with ASME, API, ISO, and AWS codes
- Sensitivity can be dialled up via fluorescent systems
Our Inspection Process
- 1
Pre-cleaning
Remove scale, paint, oil, and contaminants to expose surface-breaking defects.
- 2
Penetrant application
Apply visible or fluorescent penetrant; allow controlled dwell time per code.
- 3
Excess removal
Wipe or solvent-clean surface without flushing penetrant from defects.
- 4
Developer & inspection
Apply developer and inspect under white or UV-A light at code-mandated intensity.
- 5
Reporting
Document indications with photographs, sketches, and code-based accept/reject.
Applications
- Weld toe and root inspections
- Castings, forgings, and extrusions
- Aerospace and turbine components
- Pump, valve, and impeller bodies
- Stainless steel fabrications and food-grade equipment
- Pressure-retaining boundary inspections
Codes & Standards
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