Non Destructive Testing

Phased Array ultrasonics is an advanced method of ultrasonic testing that has applications in nondestructive testing. The Phased Array probe consists of many small ultrasonic elements, each of which can be pulsed individually. By varying the timing a pattern of interference is set up that results in a beam at a set angle. Basically, the beam can be steered electronically. The beam is swept back and forth searching the object being examined and the data from multiple beams is put together to make a visual image showing a slice through the object.

Advantages:

• Same as conventional ultrasonics
• Increased sensitivity
• Visual images showing indications

Disadvantages:

• Extra training is required prior to use
• Equipment is more expensive

Magnetic Particle testing is a method for detection of surface and sub-surface defects in ferrous materials. By using an externally applied magnetic field or electric current through the material, and the principle that the magnetic flux will leave the part at the area of a flaw.

The presence of a surface or near surface flaw in the material causes distortion in the magnetic flux through it, which causes a leakage of the magnetic fields at the flaw. This leakage will “hold” magnetic particles in the area, revealing the flaw to the technician.

Advantages:

• Easy to perform
• More sensitive than plain visual inspection
• Will work through paint

Disadvantages:

• Equipment is bulky and unable to fit into some areas
• The method only works on ferrous materials (does not work on stainless steel)
• Only able to detect flaws approximately ¼” below the surface.

Dye Penetrant testing is a method used to locate surface-breaking defects in all non-porous materials (metals, plastics, or ceramics). A low surface tension fluid is applied to the component which penetrates into clean and dry surface-breaking discontinuities. After adequate penetration time has been allowed, the excess penetrant is removed, and developer is applied. The developer helps to draw the penetrant out of the flaw where a visible indication becomes apparent.

Advantages:

• Works on both ferrous and non-ferrous materials
• Works on all non-porous materials (metals, plastics, or ceramics)
• Increased sensitivity with high visual contrast
• Easy to perform

Disadvantages:

• Will not work through paint
• Only able to detect flaws open to the surface
• Components with poor profile are difficult to inspect

Visual testing is a method where an inspector visually searches a component for defects in welding and configuration. Visual testing can be done on any material and any component following a predetermined set of guidelines. A visual test is usually performed alongside other testing methods. Another form of Visual testing is Quality Control. Quality Control is a method where procedures, processes, and specifications are reviewed alongside a component to ensure proper quality is obtained.

Advantages:

• Can be performed on any material or configuration
• Can be performed quickly in comparison to other methods
• Can be used to ensure quality

Disadvantages:

• Cannot be used to find internal flaws
• Is not as sensitive as other methods

Eddy Current uses alternating magnetic pulses to induce small electrical currents within the part. These currents can be detected by their magnetic fields to give information about the part. Cracks and other defects can be detected near the surface or the part without removing coatings.

X-ray can be used to see inside the part and identify flaws that are hidden from view.

Our system uses florescent plates that are exposed similar to traditional film. The plates are then scanned into the computer to give us a digital image. This image can be viewed on any computer. The digital images can be more easily archived for future viewing or easily shared between departments for review.

Advantages:

• Full view of part including hidden inner areas.
• Permanent record of parts for future analysis.
• Test can be done on almost any shape or surface condition.

Disadvantages:

• Area around part must be cleared of personnel to avoid radiation exposure.
• Access to both sides of the part are required.
• For field inspection applications it takes approximately an hour to get set up for the first shot.

Positive material identification (PMI) is used to analyze and identify material grade and alloy composition for quality and safety control.

A rapid, non-destructive method, positive material identification is performed on a wide range of components and assets, and provides a semi-quantitative chemical analysis. It is used for both material verification and identification.

The method is utilized for quality control and safety compliance, and is an integral part of both production and asset integrity management across many industries including oil and gas, power, chemical, pharmaceutical, nuclear, aerospace and fabrication.

Positive material identification can prevent potential product failure in manufacturing. At oil and gas, power generation and pharmaceutical plants, pre-service and in-service inspection of critical components and welds with PMI can prevent breakdown and its costly consequences.   

PMI can: (High Alloy Steel, and other metals)

• Ensure products/components have been manufactured using the correct alloy
• Find potentially mixed-up alloys
• Identify if the wrong material has been used
• Ensure material conforms to the correct standard and specification (both customer and industry)
• Ensure welded components have used the correct filler material

PMI CAN NOT:

• Detect the carbon and other small elements within the material
• Give accurate data to calculate carbon equivalency (Grade of carbon steel)

Positive material identification is performed using either of the two techniques below:

• X-ray Fluorescence (XRF) analyzer: This is the most common method and the portability of the hand-held equipment allows Intertek to perform PMI on-site at our customers’ premises. The device scans the metal material and identifies its key elements. However, it cannot detect carbon and some lighter elements and is not suitable for identification of pure carbon steel materials.
• Optical Emission Spectroscopy (OES): This method can detect almost all types of elements including carbon and lighter elements and carbon steel. This method is not portable and we DO NOT offer this for field inspections. We will have to send a sample to the lab for testing.