NDT Steel Metal

8/13/2019 NDT Steel Metal

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NDT for Steels/metals





Finished product quality control

Requirements in this area for flat and long products include:

internal quality - presence inclusions or clusters of inclusions, cracks, microstructure

heterogeneities surface condition - surface defects, surface cracks, under-skin defects,

roughness, brightness, dimensional properties - length, width, shape, evenness,straightness, thickness and thickness profile, product sorting and characterization in

accordance with applications properties, and uniformity of mechanical properties

Why NDT?



Infrared Thermography



Advanced Ultrasonic testing (PA/TOFD)

PHASED ARRAY (PAUT)

PA is an advanced method of ultrasonic testing. Instead of a single transducer andbeam, phased array uses multiple ultrasonic elements and the flaw imageobtained with multiple angles and beams give a more accurate flawcharacterization than conventional ultrasonic inspection.

This in turn facilitates fitness for service modelling and predictions.

High-speed inspection using single-axis scans instead of conventional raster scan

PA can be done manually, in semi-automated or a fully automated mode.For corrosion mapping application alinear array probe mounted on a wheelis used.



Advanced Ultrasonic testing (PA/TOFD)

TIME OF FLIGHT DIFFRACTION

TOFD method of ultrasonic testing is a sensitive and accurate method for thenon-destructive testing of welds for defects. The use of TOFD enabled crack sizesto be measured more accurately, so that expensive components could be kept in

operation as long as possible with minimal risk of failure.

Due to its sensitivity and sizing accuracy, TOFD is also an excellent tool for in-service material and flaw monitoring.

Phased array & TOFD inspection can bedone simultaneously, which increases theprobability of defect detection andmeasurement of length and height of thedefect to a high precision. This helps indetecting and discriminating the fatiguecracks which leads to catastrophicfailures.



Radiography(DR/CR)

Digital/Direct Radiography (DR) is a form of x-rayimaging, where a flat panel detector is used insteadof film. With DR systems the images can be viewedon the monitor immediately after acquisition, whichtakes few seconds and can be stored/ forwardedwherever they are needed. As these images aredigital, multiple copies of the image data are alwaysidentical.

Computed Radiography (CR) uses very similarequipment to conventional radiography except thatin the place of a film to create the image, an imagingplate (IP) made of photo stimulable phosphor is used.Hence instead of taking an exposed film into a darkroom for developing in chemical tanks, the imagingplate is run through a special laser scanner, or CRreader, that reads and digitizes the image. The digitalimage can then be viewed and enhanced usingsoftware.



REMOTE VISUAL INSPECTION

RVI is used to visually inspect plant components for surface defects, generalcondition, degradation, blockages & foreign materials. It can be used asstandalone inspection or as a complement to other NDE techniques, such as eddycurrent, ultrasonic or X-ray, in order to qualify unclear signals or pinpoint where amore thorough inspection is needed.

RVI of large surface areas requires an industrial Pan, Tilt, and Zoom (PTZ) camera.For RVI of pipes, we use steerable crawler to inspect pipes of various diameters.These crawlers are well suited for carrying out inspections on pipe systems,especially those that have a lot of bends and pipe branches.



Electromagnetic Acoustic Transducers

EMAT technique providing accurate

thickness (with accuracy of +/- 0.127mm)readings with none or minimal tubesurface preparation. The probe withintegrated encoder and light indicators(for fast visual alert to the operator) ismanually scanned along the boiler tubewhile the system records the thickness &alarms if the tube is below a pre-programmed threshold or other defectconditions are triggered. The system savesa complete record of each tube & thewhole boiler for later post analysis &tracking.

MRUT (Medium Range Ultrasonic Testing)uses higher frequency guided waves todetect corrosion, cracks anddiscontinuities on exposed tubes, gaslines, oil pipelines and storage tanks.

MRUT



Thank You

Presented byDhanasekaran

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NDT Steel Metal