Liquid Penetrant Inspection – CMH

Conventional NDT Services

Liquid

Penetrant Testing

Detect fine surface-breaking cracks, porosity, seams and other open discontinuities in welds, castings, forgings and non-porous components—without damaging the part.

Inspection Snapshot

Reliable crack detection at the surface

Weld Examination

Visible and fluorescent penetrant methods

Crack Detection

Surface-breaking discontinuities

Broad Material Compatibility

Steel, stainless steel, aluminum, alloys and other non-porous materials

Discuss your inspection

Certified Personnel

Qualified NDT professionals

Fast Turnaround

Responsive scheduling

Modern Equipment

Calibrated UT instruments

Detailed Reports

Clear inspection findings

Highly Sensitive

Reveal fine cracks while keeping the component fully usable.

What is liquid penetrant testing?

Reveal surface-breaking flaws with high sensitivity

Liquid Penetrant Testing (PT), also called Dye Penetrant Inspection (DPI) or Liquid Penetrant Inspection (LPI), is a non-destructive method used to reveal surface-breaking discontinuities in non-porous materials.

A low-viscosity penetrant is applied to the prepared surface and allowed to enter open discontinuities by capillary action. After the excess penetrant is removed, a developer draws trapped penetrant back to the surface, creating visible indications for evaluation by a qualified inspector.

Weld inspection

Surface-breaking cracks

Porosity open to surface

Fatigue cracking

Forgings & castings

Leak path indications

--------- Our Process ---------

A controlled inspection from preparation to report

Every job is planned around the material, component geometry, surface condition,
inspection access and applicable acceptance criteria.

Scope Review

We review the material, surface condition, geometry, access, penetrant family and applicable acceptance criteria.

Surface Preparation

The inspection area is thoroughly cleaned and dried so contaminants do not block discontinuities or create false indications.

Apply, Remove & Develop

Penetrant is applied and allowed to dwell, excess penetrant is removed, and developer is applied to draw out trapped penetrant.

Evaluate & Report

Relevant indications are examined under suitable visible or UV-A lighting, documented and compared with applicable acceptance criteria.

--------- Inspection capabilities ---------

Liquid penetrant testing for non-porous components

Our PT/LPI services support fabrication quality control, maintenance inspection, repair verification, leak-source evaluation and failure investigations.

Weld Inspection

Inspect weld surfaces and heat-affected zones for cracks, porosity, lack of fusion open to the surface and other relevant indications.

Forgings & Castings

Reveal cracks, laps, seams, cold shuts and other discontinuities that are open to the surface.

Machined Components

Evaluate machined parts, castings, forgings and components after grinding, forming, heat treatment or service exposure.

Visible & Fluorescent PT

Select visible colour-contrast or fluorescent penetrant systems to suit the component, inspection environment and required sensitivity.

In-Service Inspection

Check welds, pressure components, piping, machinery parts and other accessible surfaces for fatigue or service-induced cracking.

Repair Verification

Inspect repaired, blended or ground areas to verify that relevant surface-breaking discontinuities have been removed.

--------- Discontinuities ---------

What liquid penetrant testing can detect

Detection capability depends on the discontinuity being open to the surface, surface cleanliness, dwell time,

penetrant sensitivity, developer application and inspection lighting.

Surface Cracks

Fatigue Cracks

Grinding Cracks

Quench Cracks

Weld Cracks

Seams

Laps

Cold Shuts

Tears

Surface Porosity

--------- Codes & standards ---------

Inspection aligned with your requirements

Testing can be performed to applicable customer procedures, drawings, specifications and recognized industry standards. The final technique is confirmed after reviewing material compatibility, surface condition, geometry, cleaning restrictions and acceptance criteria.

ASTM E1417

Liquid penetrant testing

ASTM E165

Penetrant examination guide

ASME V

Article 6 requirements

AWS D1.1

Structural welding

ISO 3452-1

Penetrant testing principles

Client Spec.

Project requirements

--------- Industries served ---------

Supporting quality, safety and asset integrity

Oil, Gas & Pipeline

Construction & Infrastructure

Energy & Power

Manufacturing

What our clients say

Frequently asked questions

Answers before you schedule

Share the component type, material, dimensions, surface finish, inspection location and applicable standard so we can recommend the correct penetrant technique.

Does liquid penetrant testing damage the component?

No. PT/LPI is non-destructive. Penetrant, remover and developer residues are cleaned from the component after inspection using a compatible post-cleaning method.

What materials can be inspected by liquid penetrant? ＋

Liquid penetrant testing can be used on many non-porous materials, including carbon steel, stainless steel, aluminum, nickel alloys, titanium and certain ceramics or plastics. It is generally unsuitable for porous, heavily scaled or very rough surfaces.

Can testing be completed on-site?

Yes. CMH Metlabs can provide laboratory and field liquid penetrant inspection, subject to site access, ventilation, lighting, surface preparation and consumable-use requirements.

What information is needed for a quotation?

Please provide the material, component type, dimensions, quantity, inspection area, surface finish, coating condition, location, applicable code and required turnaround time.

Can liquid penetrant detect defects below the surface?

No. Liquid penetrant testing only reveals discontinuities that are open to the inspected surface. Ultrasonic or radiographic testing may be required for internal defects.

--------- Need an inspection? ---------

Reveal surface defects before they become failures

Send us your material details, component drawings, inspection area and applicable acceptance criteria for a practical testing recommendation.

Contact CMH Metlabs

Plan your liquid penetrant inspection

Our team can help confirm material suitability, the appropriate visible or fluorescent technique, surface preparation and reporting requirements.

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