Written by our staff experts, these papers provide a valuable source of leading edge research within the NDT Industry.
Authors: Mohammad Marvasti, Mike Matheson, Michael Wright, Deepak Gurjar, Philippe Cyr, Steven Peters
An ultrasonic phased array system is described for online inspections of welds or condition monitoring of parent material at elevated temperatures of up to 350°C. Wedges are built from plastics resistant to high temperature degradation, and equipped with a cooling jacket around the array. A model of the ultrasonic beam skew pattern due to thermal gradients inside the wedge was developed. The model is used in a separate algorithm to calculate transmission and reception time delays on individual array elements for generation of plane waves in a hot test piece, while compensating for thermal gradients effects inside the wedge. The algorithm results were used to develop a high temperature phased array inspection technique (HTPAUT). Experimental verifications of the developed technique indicate that plane waves can be generated efficiently in a hot test piece to locate flaws in the piece within the same level of accuracy achieved through room temperature inspection of the same piece.
Keywords: High Temperature Inspection, HTPAUT, Phased Array Beam Formation, Focal Laws, Law File
Authors: Larry Etherington, Alistair MacRaild
This paper investigates the practical challenges of the application of ultrasonic inspection of Engineered Material Components (EMC) at elevated temperatures. ESBeamTool HighTemp is a visualization tool indicating the relative temperature changes within the Phased Array (HTPAUT) wedge as it relates to high temperature material evaluation. The variations in the wedge must be taken into account. It is these wedge temperature variations, which dictate the ultrasonic beam exit point at the material interface, producing predictable material inspection angles according to Snell’s law.
Keywords: High temperature inspection, HTPAUT, phased array beam formation, law file
Authors: Ed Ginzel, Oleg Volf, Ben Brown
Since the late 1980s automated ultrasonic testing of production welding on pipeline (AUT) has been the preferred NDT method. The technique that has proven to be the most efficient in way of data acquisition, analysis and accuracy, has been termed the zonal discrimination technique. Until recently, no other technique provided the speed required to keep up to the production rates possible by automated welding. With the advent of phased-array technology and faster computers, a new approach is feasible that can augment or even replace the older zonal technique. This paper describes how the Full Matrix Capture (FMC) and Total Focussing Method (TFM) have advanced to provide superior displays and analysis tools for production pipeline weld inspections. Examples are provided illustrating ease of setup, simplicity of analysis and sizing capabilities. The technique is applicable to a wide range of wall thickness and may offer an alternative to the use of the complex calibration blocks associated with the zonal discrimination technique.
Keywords: AUT, pipeline, FMC, TFM, ultrasonic
Authors: Robert Ginzel, Ed Ginzel
Nozzle weld inspections have long been an important function carried out by ultrasonic test methods. When performed using manual techniques the plotting of located defects is a time-consuming ordeal requiring local profiles, wall thickness readings and compensation for curvature effects. The introduction of Code Case 2235 for ASME compliant vessels has allowed many welds in the vessel to be inspected using ultrasonic methods. The computerisation requirement in the Code Case is easily applied to longitudinal and circumferential butt welds. However, complexities of geometry can limit the useful application of ultrasonic methods to nozzle welds unless provision is made for the mechanics to provide adequate tracking to assure full-volume beam coverage.
This paper discusses the options available when phased-array techniques are used with mechanical apparatus that provides encoded motion from the inside surfaces of the nozzle. Modelling provides evidence of the physical parameters that must be considered for full coverage. Actual scan results are provided to indicate how well the models predict the coverage by detecting targets at the edges of the weld zones.
Modelled and actual results indicate that a scan-plan, using a ray-tracing programme, can provide suitable indication of required coverage. In many cases, the mechanical apparatus used to guide the probe can be designed with a minimum of complexity when scanning access is from the inside surface of either the nozzle or vessel.
Keywords: Phased array, ultrasound, nozzles, mechanised
Authors: Robert Ginzel, Ed Ginzel
Part 1 of this 2 part series of papers on nozzle weld inspections by phased array ultrasound provided background on the types of nozzle configuration and made several recommendations for scanning from the nozzle inner surfaces. Part 2 discusses scanning when access is available from the outer surfaces of the vessel for a set through configuration.
Modelling provides evidence of the physical parameters that must be considered for full coverage. Actual scan results are provided to indicate how well the models predict the coverage by detecting targets at the edges of the weld zones.
Modelled and actual results indicate that a scan-plan made using a ray-tracing programme can provide suitable indication of required coverage. In many cases, the mechanical apparatus used to guide the probe can be designed with a minimum of complexity when scanning access is from the outside surface of either the nozzle or vessel.
Keywords: Phased array, ultrasound, nozzles, mechanised
Authors: Ed Ginzel, Dave Stewart
The technique of inspecting pipeline girth welds using zonal discrimination has been used extensively since the late 1980s. Refinements in the past decade have included the introduction of phased-array equipment, improved sizing algorithms, developments for small diameter pipe and techniques for exotic alloys, to mention a few.
Until recently, inspecting pipeline girth welds using zonal discrimination has not taken advantage of modelling in the same way as other applications. Simple ray-tracing software has provided a good means for operators to calculate probe positioning and focal law limitations for coverage; however, the effects of flaw characteristics and focusing parameters has not been studied with modelling in the same way it has in the power generation applications.
This paper looks at the use of the analytical modelling software called CIVA as a tool to investigate many of the issues facing pipeline AUT.
Keywords: Phased array, zonal discrimination, ultrasound, modeling, CIVA
Authors: David Cziraki and A Danis
The expansion of the Brazilian Samarco Mineração S.A. mining production facility required the construction of a second iron ore slurry pipeline. This upgrade interconnects the facilities of Samarco in Mina do Germano, Minas Gerais, with Ponta Ubu in Espiritu Santo. The project involves 340.6 km of 16" and 57.8 km of 14" steel pipe, and includes several new pumping, pressure measuring, and valve stations. At full production capacity the new pipeline will convey 16.5 million tons per year, in addition to the current 13.5 million tons per year.
In early April 2006, Eclipse Scientific Pipeline AUT Group and Materials Research Institute were contracted by NDT Do Brasil to act as project start-up consultants for the client’s impending entry into the pipeline girth weld inspection market.
Keywords: Girth Weld AUT, TOFD, POD
Authors: Robert Ginzel, James Pennie, Jim Marr
Stress corrosion cracking (SCC) is now globally recognized by pipeline operators as a significant threat to the safe and efficient operation of their systems. Onshore natural gas, oil and refined products line pipe steels have all been susceptible to this form of environmentally assisted cracking, which can develop as either low or high pH SCC. Over the years, the pipeline industry has developed several non destructive examination (NDE) techniques to identify, document and evaluate the severity of a SCC indication, including magnetic particle inspection (MPI) and ultrasonic (UT) sizing.
While MPI can locate and assess the surface dimensions of the cracks within the SCC indication, measurements of crack depth within the colony have not been as easily obtained under field conditions. Researchers have been developing field based hand held ultrasonic (UT) sizing techniques to determine the actual crack depths. The UT determined SCC crack depths are incorporated into engineering assessments and crack growth models (used in risk algorithms), potentially enabling operators to effectively address, monitor and thus manage this time dependent threat. This paper will discuss our experiences since the mid 1980’s with UT crack sizing, the techniques that are available in the industry, the limitations that still exist, and the benefits of using a new UT assessment transducer to assess SCC crack depths.
Keywords: Stress corrosion cracking, ultrasonic, magnetic particle inspection
Authors: Brent Zeller, Philippe Cyr, Erica Schumacher, Ed Ginzel
In May of 2009, the NRU (National Research Universal) reactor was forced to shut down after a small heavy water leak. In 2009-2010 repairs were performed in order to restart medical isotope production mid-August 2010. Since the NRU’s return to service, a series of periodic inspections is required to ensure the safe operation of the reactor.
Eclipse Scientific was mandated to develop the NDE procedures and robotic manipulator for the In-Service Inspection program of the NRU vessel. This included the development and implementation of phased array ultrasonic inspection techniques and eddy current array technology techniques to be used with unique material characteristics, property and physical state changes. The inspection mandates were required in a short time frame and environmental conditions represented very difficult delivery and inspection circumstances. This paper presents how modeling was used in the development process to achieve the inspection mandates. The modeling software used ranged from advanced ray tracing (ESBeamTool) to full UT/ET simulation (CIVA) and was key in obtaining approval of the procedures, developing good training material and obtaining excellent data from the inspections.
Keywords: Complex inspection, phased array, ultrasound, modeling, simulation
Authors: Robert Ginzel, M Moles
Phased arrays can be used for detecting cracking (and other defects) in high tensile bolts. The technique uses a “fingerprinting” approach to the bolts. In contrast to current code procedures where an operator manually scans a normal beam probe over a bolt and interprets the results, this phased array technique uses an S-scan and a mechanized scanner. Specifically, the phased array probe is mounted in contact on the head of the bolt, and performs a small angle longitudinal wave S-scan down the bolt. The array is mounted in a mechanized and encoded jig for 360o rotation round the bolt. Signals are received from the threads, bolt geometry and from mode conversions. In essence, the S-scan gives a fingerprint of the bolt at all depths and orientations when the operator scans round the bolt collecting data. Any perturbations from defects or cracks are typically very visible. Interpretation is much simpler than with alternative bolt inspection techniques. Some examples from calibration and cracked bolts will be shown. The technique can be fine-tuned for different bolt dimensions and features.
Keywords: Phased array, bolts, beam probe, S-scan
Authors: Ed Ginzel, D Johnson
This paper presents a review of the methods by which phased-array formed beams can be analysed for steering and resolution limitations. In-house methods have been developed by several users and an ASTM Standard Guide has also been produced that provides some options. However, the concepts of beam characterisations of phased-array generated pulses for NDT seem to require further discussion to avoid misuse.
Keywords: Phased array, resolution, ultrasonic, beam-steering
Authors: Ed Ginzel, Mike Matheson, B Feher
NDT use of the concept of “Probability of Detection” (POD) has been around since about the 1970s. Most recently the concept of “Probability of Rejection” has been used. A description of its premises and how it is easily adapted from the principles of POD are described here.
Keywords: Probability, Probability of Detection, Probability of Rejection, PoD, PoR
Authors: Brent Zeller, Luciano Lombardi, Philippe Cyr, H. Douglas Mair, Robert Ginzel
In May of 2009, the NRU (National Research Universal) reactor was forced to shut down after a small heavy water leak. In 2009-2010 repairs were performed in order to restart medical isotope production mid-August 2010. Since the NRU vessel‘s return to service, a series of periodic inspections is required to ensure the safe operation of the reactor. Eclipse Scientific in collaboration with Utex Scientific Instruments and Liburdi Automation developed the NDE inspection system for the In-Service Inspection program of the NRU vessel.
In addition to the difficult environmental, delivery and inspection circumstances the inspection team was faced with the problem of doing an immersion inspection of the inside surface of the reactor vessel through a small 120 mm access port at a distance of more than 10 m to the inspection area at the bottom of the reactor. The vessel was built over 50 years ago and as the inner surface was modified by the repair program during the forced outage, there were no accurate drawings of the inner surface of the vessel that an automated system could rely upon. Eclipse Scientific in collaboration with Liburdi Automation developed a robotic arm designed to enter from the remote access port to deploy the Phased Array and Eddy Current Array inspection heads into the reactor vessel. The motion control and data acquisition system was developed in collaboration with Utex Scientific Instruments using their InspectionWare software.
This paper will highlight the challenges faced in the development of an inspection system capable of using ultrasonic signals to learn a surface and, using this acquired surface topography, effectively and safely deploy and articulate the different inspection heads required to perform the In-Service Inspection of the NRU vessel.
Keywords: Complex inspection, phased array, ultrasound, eddy current array, automated inspection, motion control
Authors: David Cziraki, Philippe Cyr
The escalated use of phased array ultrasonic instrumentation combined with the growing complexity and diversity of the associated applications has given rise to the requirement for enhanced inspection technique development. The standard tools used for conventional UT technique development fall short of the requirements for advanced techniques. Pencil and protractor fail to achieve the new enhanced objectives. These increased expectations of reporting, documentation and efficiency translate directly to greater demands on the technician.
Keywords: Phased array, ESBeamTool, technique development, ultrasonic modeling
Authors: Ed Ginzel, Mike Matheson, Philippe Cyr, Ben Brown
Civa is a well known analytical software program that has been extensively validated by field demonstrations. BeamTool is a much simpler software programme that has features that are useful for technique development and preparing images suitable to use in the preparation of scan plans that are now required in ultrasonic testing procedures. This paper provides an indication of the how close the traditional equations for several of the parameters calculated in BeamTool are as compared to the more accurate methods used in Civa. The features validated include near-field distance, beam divergence and refracted angles for both round and rectangular shaped elements.
Keywords: Modeling, validation, ultrasound, Civa