Other Services

Positive Material Identification or PMI

Positive metal identification can be used when:

• working with a part that is part of an assembly or that is too large for shipping, a sample cannot be cut for routine testing,
• a mixed lot is suspected,
• material identification/documentation has been misplaced,
• there are questions about samples too costly to destroy.

Hardness Testing

Hardness testing measures a material’s resistance to permanent deformation by pressing a harder material into it. The test provides a numerical value that describes the material’s strength, wear resistance, and other mechanical properties. 

Here’s how hardness testing works:

1. A standardized indenter is pressed into the material being tested with a specific force and for a set amount of time. 
2. The indenter deforms the material’s surface, leaving an impression. 
3. The depth or size of the impression is measured, and a hardness value is assigned to the material. 

The hardness value is expressed in a unit of measurement, such as kilogram force (kgf), Newton (N), Vickers hardness (HV), Brinell hardness (HBW), Knoop hardness (HK), or Rockwell hardness (HRA, HRB, HRC). 

Hardness testing is used in many industries, including metallurgy, quality control, and material selection. It can help determine if a material is suitable for its intended use. 

Holiday Testing

Holiday testing, also known as continuity testing, is a non-destructive method for detecting defects in coatings and linings. It’s used to find holes, or “holidays”, in coatings that are too small to see with the naked eye. Holiday testing is important because it helps ensure the integrity of coatings, which can prevent corrosion and extend the lifespan of materials. 

Holiday testing involves passing an electrical current through a coating and looking for a spark that indicates a defect. The type of test used depends on the thickness of the coating and the conductivity of the substrate:

• Low-voltage testingAlso known as the wet sponge method, this is typically used for coatings less than 500 microns (20 mils) thick.
• High-voltage testingAlso known as spark testing, this is typically used for coatings thicker than 20 mils, but can be used for thinner coatings if the voltage is set correctly. High-voltage testing requires special care to avoid damaging the coating or injuring the operator. 

Holiday testing is often used in the offshore industry, where piping and structures are coated with non-conductive materials. 

Pulsed Eddy Current

Pulsed eddy current is an advanced electromagnetic inspection technology used in detecting flaws, measuring the thickness of steels and detecting corrosion in ferrous materials typically hidden under layers of coating, fireproofing or insulation.

A magnetic field is created by an electrical current in the coil of a probe. When the probe is placed on the insulation, fireproofing, or coating, the field penetrates through all the layers and stabilizes in the component thickness, and then the electrical current in the transmission coil is turned off, causing a sudden drop in the magnetic field. As a result of electromagnetic induction, eddy currents appear in the component wall. The eddy currents diffuse inward and decrease in strength. The decrease in eddy currents is monitored by the PEC probe and used to determine the wall thickness. The thicker the wall, the longer it takes for the eddy currents to decay to zero.

PEC is therefore the analysis of transient eddy currents in a conductive component following a sharp electromagnetic transition.

Pulsed eddy current can be used:

• On outer surfaces with or without insulation or aluminium, stainless and galvanized steel weather jacket, blistering scabs, or fireproofing
• Near pipe elbows, supports, valves, and other metallic structures such as nozzles, and flanges
• Through concrete, polymer coatings, metallic mesh, and rebars.

Replication Metallography

Replication metallography is the use of thin plastic films to non-destructively duplicate the microstructure of a component. The film is then examined at high magnifications.

The typography of a surface is copied by casting or impressing material onto the surface. It is the commonly used technique to duplicate surfaces that are inaccessible in metrology to other forms of non-destructive testing.

Replication metallography is a cost-effective testing method that can be done on-site. Large or irregularly-shaped specimens may be replicated with relative ease.

Pipelines

Often failure of one critical pipeline is enough to shut down an entire plant. Such pipelines can be regularly permanently monitored using Acoustic Emission for propagating cracks/defects and leaks. Lines may be monitored after integrity concerns have been raised, allowing repairs to be undertaken during a scheduled shutdown opposed to an emergency shutdown.

Structural Monitoring

Areas that are difficult to access and inspect can be effectively monitored for crack initiation and growth by using acoustic emission (AE) technology.

For structures loaded randomly such as offshore platforms, continuous monitoring is necessary. In addition to AE, the acquisition of dynamic strain data gives essential information on structural behaviour, helps with life prediction, and aids analysis when cracking is suspected.

IRIS

IRIS Can be used when doing tube inspections.

Field-proven and commonly used in boilers, heat exchangers, and fin-fan tubes.

Often used as a back-up to electromagnetic examination of tubes, to verify calibration and accuracy. Especially useful as a follow-up to remote field testing due to the full sensitivity near tube support structures provided by IRIS.

• The IRIS probe must be moved very slowly (approximately 1 inch per second, or 2.5 cm/s), but it produces very accurate results (wall thickness measurements typically accurate to within 0.005 inch, or 0.13 mm).
• Before the examination, tubes must be cleaned on the inside to bare metal.
• A supply of clean water is needed, typically at a pressure of 60 psi, or 0.4 MPa. Dirt or debris in the water may cause the turbine to jam.
• Works for tube diameters of ½ inch (13 mm) and up.
• Special centralizing devices are needed for larger diameters.
• Works in metal or plastic tubes.
• Through hole is difficult to detect by using this method.
• Operates in temperatures above freezing.
• Can pass bends, but will not detect defects in bends.
• Not sensitive to cracks aligned with tube radius.