4 Advice to Choose a Non Destructive Testing Products

Non Destructive Testing (NDT) covers a huge array of techniques used for detecting and evaluating flaws in materials and objects without damaging the material that is being tested.  It&#;s used across a variety of industries and applications, notably where equipment or component failure could impact negatively on costs, safety and performance.

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Each method has advantages and disadvantages and some will be ideal for certain applications but of little or no value in another situation &#; so it is important to choose the NDT method that is right for the job.

The following table provides a brief summary of the most commonly used techniques, their main uses and the advantages and disadvantages of each method &#; and technicians and engineers may find this information helpful when deciding which method is most suitable for a particular application.

METHOD MAIN USES   ADVANTAGES   DISADVANTAGES Visual Testing

In-service inspections

 

Minimal training required

Immediate results

Portable

Limited scope of testing

Restricted to observing and identifying obvious visible surface discontinuities, which are generally larger in size

Requires adequate illumination of the test surface

Liquid Penetrant testing (PT) Used to locate cracks, surface defects, porosity over large surface areas that may not otherwise be visible.

Portable

Minimal equipment investment

Simple and accurate

Rapid testing

Immediate results

Can test large surface areas/volumes  and complex parts

Needs cleaning afterwards

Chemical handling required

Only locates surface defects

Relies on visual detection

Only works on smooth surfaces

 

Eddy Current testing

Detects surface and near-surface flaws such as cracks in conductive materials

Also used to differentiate materials based on their conductivity and magnetic permeability

Measures thickness of steels

Detects corrosion

Used on vessels, storage tanks, piping systems and columns etc and for tube and wire testing

 

Portable

Minimum preparation

Immediate results

Highly sensitive

Can be used for a number of industry applications, not just flaw detection eg the rapid sorting of small components for flaws, size variations or material variation

 

Equipment relatively expensive

Requires more skills and training than other methods

Rough surfaces may interfere with test

Only works on conductive materials

Limited penetration depth

 

Ultrasonic testing

(UT)

Measures changes in material thickness and changes in material properties

Locates surface and sub-surface flaws

Superior depth penetration

Tests more than just flaws

Portable

Cost-effective

Fast results

Suitable for wide range of materials/thicknesses including metals, plastics and wood

Superior depth of penetration

Only requires single-side access

Requires highly skilled technician

Surfaces have to be accessible

Surface finish can affect inspection

May miss linear defects which are parallel to the sound beam

Magnetic Particle Testing Detects surface and near-surface flaws in ferromagnetic materials

Relative low cost of equipment

Limited skills required

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Enables rapid inspection of large surface areas and/or complex parts

Sensitive to small discontinuities

Less surface preparation required than for liquid penetrant testing

Highly visible indications

 

Can only be used on ferromagnetic materials (ie those that can be magnetised)

Some site preparation required and parts must be cleaned and demagnetised afterwards

Relatively smooth surface required

Surfaces must be accessible

Results can be affected by non magnetic coverings, eg paint

 

Radiographic testing (X-ray)

Used to detect  flaws in virtually any material (surface, sub-surface and internal)

Also used to measure material thickness

Minimal preparation required

Suitable for just about any material

Can locate and measure hidden, internal features or parts

No disassembly required when inspecting multi-layered and complex structures

Relatively  high financial investment

Requires high degree of operator training, skill and experience

Radiation hazard

Usually requires access to both sides of the structure

 

Isotope Radiography Detecting surface and internal/hidden flaws

Portable

Cheaper than X-ray equipment

Suitable for inspecting hidden areas

Minimal site preparation

 

Safety hazard

Requires highly skilled operator

Sensitive to flaw orientation so operator experience is vital for correct interpretation of results

This table is not intended to be prescriptive nor exhaustive and given that NDT plays such a crucial role in ensuring that structural and mechanical components perform their function in a safe, reliable, and cost-effective way, it&#;s imperative to make the right choice of testing method for a particular application.

If you would like advice from an experienced professional about which NDT method will best meet your needs, you should give Nexxis a call.  They are a leading Australian supplier of technical equipment and have an extensive range of NDT tools for purchase or rent, plus they can customise a solution that will fulfil your requirements.  Call them on or visit their website, nexxis.com for more information.

 

NDT is typically used to inspect materials and components for flaws, such as cracks, voids, inclusions, and porosity. This method can also be used to measure the thickness of materials, the hardness of metals, and the properties of composites.

Why is NDT Testing Important?

Non-destructive Testing is a critical tool in ensuring the safety and quality of products and systems. It can be used to test for a variety of potential problems, from cracks and other defects to manufacturing issues. By catching these problems early, NDT can help avoid costly repairs or replacements down the line.

NDT is essential  in ensuring the quality and safety of products and materials. It can be used to:

• Detect defects

• Assess the strength of a material

• Verify the dimensions of components

• Ensure that products meet the required standards for

  quality control

What is the Difference Between Non-destructive Testing and Destructive Testing?

There are two main types of testing that are used to evaluate the strength and integrity of materials: destructive testing and non-destructive testing. Destructive testing involves causing damage to the material in order to test its limits, while non-destructive testing allows materials to be tested without causing any damage.

Each type has its own advantages and disadvantages. Destructive testing is often more accurate than non-destructive testing but can only be used on a limited number of materials. Meanwhile, non-destructive testing produces less accurate results but can be used on a wider range of materials.

Which type of testing is right for your needs will depend on a variety of factors, including the type of material being tested and the accuracy required.

What are the Main Types of NDT Methods?

There are a variety of different non-destructive testing methods. Each of these techniques can be used to detect different types of defects, so it is important to choose the right one for the job. The most common NDT methods are:

1. Visual Testing

Visual testing is the simplest and most common form of NDT. It is often used as a first step in the NDT process to identify potential areas of concern. It involves visually inspecting the surface of the material for defects such as cracks, scratches, or other irregularities. However, it is limited by the inspector&#;s ability to see the defect.

2. Radiographic Testing

Radiographic testing uses X-rays or gamma rays to penetrate the surface of the material and create an image of the internal structure. This image can then be analyzed for defects. Radiographic testing is useful for detecting internal damages that are not visible from the outside.

3. Ultrasonic Testing

Ultrasonic testing uses high-frequency sound waves to detect defects in the material. The sound waves are sent into the material and will bounce off of any defects that are present. The echoes are then converted into an image that can be analyzed for defects. Ultrasonic testing is useful for detecting both internal and external defects.

4. Magnetic Particle Testing

Magnetic Particle Testing, also known as Magnetic Particle Inspection (MPI), uses magnetic fields to detect surface and subsurface defects in ferromagnetic materials. A magnetic field is applied to the material, and iron particles that are magnetized by an electrical current are used to highlight any flaws present in the product. Magnetic particle testing can be used to detect cracks, voids, leaks, or indications.

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Factors Considered When Conducting Non-Destructive Testing

There are several factors considered before conducting NDT in order for the results to be correct and concise. These factors are as follows:

• Researching the suitable NDT method for the product

• Obtaining proper requirements for safe and reliable operation

• Characteristics of processes such as properties of materials used

• Usefulness of the available methods

• Economic value of the testing to be conducted

  Contact us to discuss your requirements of Thickness Gauge. Our experienced sales team can help you identify the options that best suit your needs.