Non-destructive testing

All posts tagged Non-destructive testing

Liquid Penetrant Testing – Advantages, Disadvantages & Alternatives

by Ishita Kapoor on January 5, 2019

Out of all the non-destructive testing techniques, only a few are suited for every type of application. For instance, on most composite materials, electromagnetic testing techniques don’t work, while computed tomography and X-rays are ideal. Likewise, ultrasounds are adaptable, but require appropriate coupling and direct contact with the surface under test, which is not possible in all cases.

What’s Liquid Penetrant Testing? 

Liquid penetrant testing, also known as dye penetrant inspection (DPI) or liquid penetrant inspection (LPI) is one of the most common and affordable solution and one of the oldest, if compared to non-destructive testing challenges. 

The method leverages capillary action, i.e, the ability of a liquid to flow into narrow spaces without help, even in opposition to, external forces such as gravity—to detect surface-breaking defects.

The excess is removed and a developer is applied after applying the penetrant and letting it dwell for a certain period. From surface-breaking defects, the developer draws the penetrant where it’s seeped, revealing their presence.

Advantages of LPI

Liquid penetrant testing has the following advantages:

  • Works on complicated geometric shapes
  • LPI materials are compact
  • Sensitive to small surface interruptions
  • Few material limitations such as—works on non-metallic, metallic, non-magnetic, magnetic, non-conductive and conductive materials
  • Liquid penetrant testing materials are individually very cost-effective
  • Visual, real-world results

Disadvantages of LPI

Liquid penetrant testing has the following disadvantages:

  • Extensive, time-taking pre-cleaning critical—surface contaminants can mask defects
  • Sensitive to surface-breaking defects only
  • Direct connection to the surface under test necessary
  • Works on relatively non-porous surface materials only
  • No depth sizing
  • Multi-process testing procedure
  • Time-taking; post-cleaning also necessary
  • No recordable data handy for progress monitoring
  • User dependent
  • Environmental concerns—may require disposing of chemicals and expensive handling

The biggest disadvantage is that despite lower costs and over time (cheaper materials, less training), Liquid penetrant testing is more than a screening tool; one can measure their length and locate defects, but using this method, it’s impossible to monitor the advancement of defects or determine the severity of its depth. It relegates the method to a pass/fail evaluation, that leads to discarding healthy parts and retaining unhealthy parts—which can both prove expensive.

Hence, in totality, despite the instant captivation of this cost-effective solution, it possesses various downsides that must be looked at before dismissing more progressive and more expensive inspection solutions, whether you contract inspections or perform them on your own.

Alternatives to Liquid Penetrant Testing

Eddy Current Array (ECA)

This offshoot of ECT enhances on the technology using multiplexed arrays of coils that are displayed in rows (instead of one or two coils), allowing to cover a larger area in a single scan pass. Below are the advantages of ECA:

  • Eddy current array probes offer better data than manual raster scans; the larger ECA probes lowers operator dependence
  • Making defect progress monitoring possible, data can be recorded.
  • Wider coverage significantly results in faster scans
  • The simpler ECA scan patterns makes analysis easier, quicker and accurate
  • ECA offers superior detection abilities, and correct defect positioning as the inspection data can be encoded, and—perhaps—sizing.

About IRC Engineering Pvt. Ltd.

IRC is one of the fastest growing Testing and Inspection company in India. We at IRC provide Liquid Penetrant TestingNon-Destructive Testing, Destructive Testing, Advanced NDT, Third Party Inspection, Condenser Testing, Electrical Testing, Residual Life Assessment of Power Plant, O&M Services, Fitness For Service, Civil Testing and Training services.

read more
Ishita KapoorLiquid Penetrant Testing – Advantages, Disadvantages & Alternatives

Fitness-For-Service Analysis: Needs | Advantages | Highlights & More

by Ishita Kapoor on December 20, 2018

MECHANICAL INTEGRITY

The main focus of Fitness-For-Service analysis is evaluating whether an equipment has downgraded in service and can carry on its intended function properly. 

This approach comprises in a rational decision process, enabling the engineer to decide whether the system can be controlled safely either as is, with reinforced inspection, after a requalification, or after a service or repair.

THE IMPLEMENTATION CONDITIONS

Fitness for service can be applied when:

  • The equipment design is not fully compliant with the relevant codes.
  • The equipment experienced an impact in service, during handling or in transit.
  • The non-destructive testing and equipment inspection have noticed defects beyond the admissible limits or those that have happened too early.
  • The equipment has never been examined, or only partly; the equipment acquired is old.

YOUR NEEDS

  • Feasibility of avoiding to remove the equipment from service prematurely which should only have to be returned at term.
  • Financial solution which is more economical than the replacing of the equipment.
  • Creating an administrative file to obtain a derogation.
  • Optimal utilization of the equipment based on precise assessment of its abilities.

YOUR ADVANTAGES

IRC’s Fitness-for-Service (FFS) engineering assessment is a multi-disciplinary method for assessing mechanical components to decide if they are fit for continued service. 

The typical result of an FFS evaluation is a “go/no-go” decision on continued operation. An assessment of remaining life or examination intervals may also be part of such an evaluation, along with remediation of the degradation mechanism.

IRC’s methodology is based on the approach executed by a team of engineers who specialize in pressurized equipment technology, corrosion, material, structural analysis and inspection. The statutory requirements concerning the equipment are also taken care of.

OUR OFFER

  • Based on non-destructive testing, the Fitness for service methodology includes the following steps:
  • Equipment integrity and residual life linked to kinetics,
  • Guidance concerning the integrity due to future conditions.
  • Pressurized equipment (reactor, heat exchangers, columns, LPG tanks),
  • Offshore pipelines & risers.
  • Onshore pipelines,
  • Atmospheric storage tanks which includes cryogenic (LNG),
  • The methodology can be expanded to other equipment depending upon the circumstance.
  • The damage mechanisms correlate to the below non-restrictive list:
  • Stress Corrosion Cracking (SCC),
  • Metallurgical damages (embrittlement, intermediate phases)
  • Localised corrosion, whether general, under insulation or pitting
  • Fatigue (thermal or mechanical),
  • Creep,
  • Crack-like flaws

SERVICE HIGHLIGHTS

Here are the features of FFS and Remaining Life:

  1. Flaw Type Detection: This includes-
  • Corrosion
  • Brittle fracture
  • Fatigue
  • Crack-like flaws
  • Creep
  • Hydrogen embrittlement
  • Stress corrosion cracking
  • Dents and shell deformations
  • High-temperature hydrogen attack

2. Fitness for Service Application: This includes-

  • Fired heaters
  • High-energy piping
  • Turbines
  • Pipelines
  • Power lines
  • Headers
  • Pressure vessels
  • Storage tanks

3. Advanced Creep Testing: Remaining Life Assessment Based on Creep Testing – IRC’s advanced creep testing service includes reliable and accurate life assessment of components prone to creep damage. This facility provides a higher level of accuracy when it comes to life assessment techniques based on actual creep property of components. Creep testing assessments lets operators optimize operating conditions, decide effective inspection intervals and extend component life.

IRC has carried out numerous projects for FFS on Piping operating at Temperature of Creep.

4. Pipeline Defect Assessment: IRC has a unique combination of major industry fracture mechanics expertise with integrity management experience, data analysis and software.

Our integrity management tools help us to support our clients with consulting and software solutions whether they are handling anomaly response plans, fitness-for-service assessments strain analysis of dents and deformations or failure analysis.

About IRC Engineering Pvt. Ltd.

IRC is one of the fastest growing Testing and Inspection company in India. We at IRC provide Non-Destructive Testing, Destructive Testing, Advanced NDT, Third Party Inspection, Condenser Testing, Electrical Testing, Residual Life Assessment of Power Plant, O&M Services, Fitness For Service, Civil Testing and Training services.

read more
Ishita KapoorFitness-For-Service Analysis: Needs | Advantages | Highlights & More

Why use Ultrasonic Phased Array instead of Radiography?

by Ishita Kapoor on September 8, 2018

Radiography and ultrasound are the commendatory nondestructive testing (NDT) techniques that can volumetrically inspect welds and components for various defects like porosity, lack of fusion, cracks etc.
Choosing the right option often depends on external process decisions or small distinctions in the detection capability for a particular test. However, Ultrasound has progressed as a replacement for Radiography, not just in practice but also in the codes of major organizations like API (American Petroleum Institute) and ASME (American Society of Mechanical Engineers).

PA is often incorporated with time-of-flight diffraction (TOFD) while the inspectors use acquisition units and scanners that can accommodate both the methods simultaneously.

Here are the Typical Advantages of Ultrasound in comparison with Radiography:

  • Accurate sizing of defect height and less number of rejects or repair while using Engineering Critical Assessment:
    • Ultrasound permits defect height measurement, enabling volumetric consideration of flaw severity.
  • High chances of detection (POD), especially for cracks and lack of fusion:
    • In most studies, Ultrasound tends to detect planar flaws better than radiography.
  • Does not cause hazard, does not emit radiation, and does not require additional licensing or personnel.
  • Does not generate any waste material or chemical (as opposed to film-based radiography).
  • Work in proximity to ultrasonic testing can continue uninterrupted. Does not require screened-off areas.
  • Setup and inspection reports are in electronic format (as opposed to film format in radiography).
  • Real-time ultrasonic analysis of welds can provide instant assessment and feedback to a welder.

 

Here are the Requirements for Typical Ultrasonic Equipment and Inspection

  • A scan plan with a procedure documenting the inspection strategy and necessary parameters. Example: Parameters that are set up with the use of NDT SetupBuilder software.
  • An acquisition unit with position-encoding ability and full, raw A-scan data retention.

Example: An OmniScan flaw detector or FOCUS PX instrument.

  • An industrial scanner (with position encoder) to repeatedly scan a weld or component semi-automatically or automatically:
    • The choice of scanner model is based on the number of pipe diameter, welds, and other application variables.
  • Deliverable data:
    • The analysis is directly executed on the acquisition unit or by the use of post-analysis with TomoView, FocusPC PC software or OmniPC.
  • Alternative acceptance criteria, as required.
  • Probes, wedges, couplant delivery equipment, and other accessories.
  • Proper training and certification of personnel.
  • Demonstrated performance of equipment, procedure, operator, and inspection process.

Conclusion

Replacing radiography with ultrasound has become a code-approved practice as well as an industry trend. The phased array equipment is convenient to use, economical, compact and associated software are accelerating the use of ultrasound. The prime reasons for this continuing trend includes improved safety of operators and others in surrounding areas, savings in process cost and time and the use of alternative acceptance criteria. The expanded use of ultrasound has led to a decrease in part rejection and repairs.

About IRC Engineering Pvt. Ltd.

IRC is one of the fastest growing Testing and Inspection company in India. We at IRC provide Non-Destructive Testing, Destructive Testing, Advanced NDT, Third Party Inspection, Condenser Testing, Electrical Testing, Residual Life Assessment of Power Plant, O&M Services, Fitness For Service, Civil Testing and Training services.

read more
Ishita KapoorWhy use Ultrasonic Phased Array instead of Radiography?

Eddy Current Array (ECA) Theory, Working and Benefits

by Ishita Kapoor on September 8, 2018

Eddy current array (ECA) is a form of non-destructive testing technology which is capable of driving various eddy current coils placed next to each other in a probe assembly. Each coil generates a signal, the strength of which depends on the amplitude and the phase of the object the probe is placed over.
The generated signal can be measured and the date can thus be recorded. Through ECA inspections, most of traditional eddy current flaw detection methods can be re-created. Additionally, ECA technology comes with excellent advantages, saving time and boosting enhanced inspection capabilities.

How it Works

ECA is a sequence of single elements arranged in a row, which enables users to cover a vast area in a single pass than conventional, single-coil probes. However, this could result to substandard results. So, ECA probes use multiplexing.
Multiplexing requires activating and deactivating coils in particular sequences supporting the width of the probe. Additionally, Multiplexing minimizes the intrusion between coils in close proximity and magnifies the resolution of the probe.
When using ECT pencil probes, ECA probes eliminate the raster scanning necessary, leaving a powerful impact on inspection speeds.

Benefits

ECA provides a number of benefits, making inspection simpler for hard-to-reach areas. It is a major improvement over single-element ECT because of the following reasons:

  • It helps in quicker inspections
  • Is less operator dependent
  • Scans a wider coverage while maintaining a high resolution 
  • It possesses better detection capabilities
  • Has simpler analysis because of easy scan patterns
  • Provides enhanced sizing and positioning because of encoded data

About IRC Engineering Pvt. Ltd.

IRC is one of the fastest growing Testing and Inspection company in India. We at IRC provide Non-Destructive Testing, Destructive Testing, Advanced NDT, Third Party Inspection, Condenser Testing, Electrical Testing, Residual Life Assessment of Power Plant, O&M Services, Fitness For Service, Civil Testing and Training services.

read more
Ishita KapoorEddy Current Array (ECA) Theory, Working and Benefits