Validation of an Ultrasonic-Phased Array Method for Testing of Circumferential Welds at Thin-Walled Pipes

NDT World ◽  
2016 ◽  
Vol 19 (3) ◽  
pp. 30-33
Author(s):  
Бросиус ◽  
David Brosius ◽  
Шуберт ◽  
Frank Schubert ◽  
Хильманн ◽  
...  
Keyword(s):  
Wall Thickness ◽  
Power Plants ◽  
Phased Array ◽  
Practical Method ◽  
Probability Of Detection ◽  
Circumferential Welds ◽  
Ultrasonic Methods ◽  
Ultrasonic Phased Array ◽  
Thin Walled ◽  
The Moment

Introduction. For testing of circumferential welds at thin-walled pipes with wall thickness lower than 6 mm using ultrasonic methods no standardization is available at the moment. Nevertheless, there are newest technologies available such as ultrasonic-phased-array technique and semi-automated handheld-scanner for pipes, with which it is possible to achieve promising and reliable results in that area. In order to bring the technique in operation in the field of coal-fired power plants or petrochemical industry a validation is needed, which will be approved by the inspecting authorities. Method. In that article we will present a successful validation of an ultrasonic-phased- array method for testing circumferential welds at thin-walled pipes with a wall thickness lower than 6 mm. Therefore, the complete geometry area was divided into several clusters, and single elements of that matrix were validated. The procedure conforms to the guideline VGB R-516 and other established standards. Besides theoretical analysis including simulations of the sound paths and reflections, extensive practical tests were performed. For this purpose six typical types of defects were analyzed by using a large number of test samples and the probability of detection was determined using this practical method. Result. The result of this work is a report for validation for each geometry cluster of the pipes including an inspection instruction and a qualification instruction for the testing equipment and the calibration samples. Conclusion. Based on that validations the ultrasonic-phased-array method was accepted by the inspecting authorities and thereby allowed to use in the regulated area of coal-fired power plants by a NDT-service provider and was applied very successful at several thousand welds.

Probability of detection of discontinuities by ultrasonic phased array inspection of 9% Ni steel joints welded with alloy 625 as the filler metal

Ultrasonics ◽  
2022 ◽  
Vol 119 ◽  
pp. 106582
Author(s):  
João da Cruz Payão Filho ◽  
Vinicius Pereira Maia ◽  
Elisa Kimus Dias Passos ◽  
Rodrigo Stohler Gonzaga ◽  
Diego Russo Juliano
Keyword(s):  
Phased Array ◽  
Filler Metal ◽  
Probability Of Detection ◽  
Alloy 625 ◽  
Ultrasonic Phased Array ◽  
Steel Joints

Ultrasonic Phased Array: Detection of Detrimental Conditions in High-Density Polyethylene Butt-Fusion Joints

2010 ◽  
Author(s):  
Caleb J. Frederick
Keyword(s):  
High Density Polyethylene ◽  
Nuclear Power ◽  
Power Plants ◽  
Phased Array ◽  
Cold Fusion ◽  
High Density ◽  
Visual Examination ◽  
Full Spectrum ◽  
Ultrasonic Phased Array ◽  
Joint Integrity

Today, commercial nuclear power plants are installing High-Density Polyethylene (HDPE) in non-safety-related and safety-related applications. While this material has numerous advantages over the carbon steel pipes that historically have been used for the same applications, developing a way to accurately inspect for joint integrity in HDPE has become increasingly important to utilities and the U.S. Nuclear Regulatory Commission (USNRC). This paper will investigate the ability to quantify the levels of detection of flaws and detrimental conditions using ultrasonic phased array, in butt-fusion joints throughout the full spectrum of applicable HDPE pipe diameters and wall-thicknesses. Perhaps the most concerning joint condition is that of “Cold Fusion”. A cold-fused joint is created when molecules along the fusion line do not fully entangle or co-crystallize. Once the fusion process is complete, during visual examination, there is the appearance of a good quality joint. However, the joint does not have the strength needed, as the required co-crystallization along the pipe faces has not occurred. Performing a visual examination of the bead, as required by the current revision of ASME Code Case N-755, does not provide adequate guarantee of joint integrity. Therefore, volumetric examination is of special concern to the USNRC to safeguard against this type of detrimental condition. Factors addressed will include pipe diameter, wall-thickness, fusing temperature, interfacial pressure, dwell (open/close) time, and destructive verification of ultrasonic data.

The Effect of Hoop Stress on the Burnthrough Susceptibility During In-Service Welding of Thin-Walled Pipelines

2008 ◽  
Author(s):  
Matthew A. Boring ◽  
William A. Bruce
Keyword(s):  
Failure Mechanism ◽  
Wall Thickness ◽  
Hoop Stress ◽  
Pipe Diameter ◽  
Welding Parameters ◽  
Minor Effect ◽  
Circumferential Welds ◽  
Welding Arc ◽  
Thin Walled ◽  
Longitudinal Welds

Most companies control the risk of burnthrough by prohibiting welding on pipelines with wall thicknesses below a specified thickness. This is a safe approach but the risk of burnthrough depends not only on the wall thickness, but also on the welding parameters and the operating parameters of the pipeline which include pressure. It is generally acknowledged that the hoop stress caused by pressurizing the pipeline has a relatively minor effect on the risk of burnthrough since the size of the area heated by the welding arc is small. While this has certainly been shown to be true for thicker materials, previous research has shown that the pressure can have a dramatic effect on burnthrough risk for thinner materials. The objective of this project was to further investigate the effects pressure and hoop stress has on the burnthrough risk of welding onto thin-walled pipelines in service. For circumferential welds, pressure and wall thickness determine the burnthrough risk and pipe diameter appears to have no effect. The failure mechanism for circumferential welds is consistently a burnthrough. For longitudinal welds, pipe diameter does appear to affect burnthrough risk even though the effect appears to be secondary to pressure and wall thickness. The pipe diameter is believed to be more influential for longitudinal welds because of the larger area of heated material that is exposed to the hoop stress. Also, the results indicate that the magnitude of the hoop stress has a direct effect on the failure mechanism for longitudinal welds (i.e., burnthrough or weld centerline cracks). For longitudinal welds, the failure mechanism is commonly burnthrough for welds made onto pipes with a hoop stress below 30% specified minimum yield stress (SMYS) which indicates that the internal pressure of the pipe is the main driving force for failure. Longitudinal welds made on pipes which are experiencing hoop stress above 30% SMYS commonly fail by weld cracking. It is important to note that even though pressure does have an effect on the burnthrough susceptibility of welds made on thin-walled pipelines, pressure only becomes a factor for welds made at heat input levels in excess of what is predicted safe by thermal analysis modeling.

Application of Ultrasonic Phased Array Techniques for Inspection of Stud Bolts in Nuclear Power Plants

2006 ◽  
Vol 110 ◽  
pp. 97-104 ◽  
Author(s):  
Sang Woo Choi ◽  
Joon Hyun Lee
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Phased Array ◽  
Nuclear Reactor ◽  
Fatigue Cracks ◽  
Ultrasonic Inspection ◽  
Phased Array Techniques ◽  
Ultrasonic Phased Array ◽  
Ultrasonic Images

The reactor vessel body and closure head are fastened with the stud bolt that is one of crucial parts for safety of the reactor vessels in nuclear power plants. It is reported that the stud bolt is often experienced by fatigue cracks initiated at threads. Stud bolts are inspected by the ultrasonic technique during the overhaul periodically for the prevention of failure which leads to radioactive leakage from the nuclear reactor. The conventional ultrasonic inspection for stud bolts was mainly conducted by reflected echo method based on shadow effect. However, in this technique, there were numerous spurious signals reflected from every oblique surfaces of the thread. In this study, ultrasonic phased array technique was applied to investigate detectability of flaws in stud bolts and characteristics of ultrasonic images corresponding to different scanning methods, that is, sector and linear scan. For this purpose, simplified stud bolt specimens with artificial defects of various depths were prepared.

scholarly journals Ultrasonic Phased Array for the Circumferential Welds Safety Inspection of Urea Reactor

2012 ◽  
Vol 43 ◽  
pp. 459-463 ◽  
Author(s):  
Dong Hu ◽  
Qiang Wang ◽  
Kun Xiao ◽  
Yehao Ma
Keyword(s):  
Phased Array ◽  
Circumferential Welds ◽  
Ultrasonic Phased Array

High-Density Polyethylene Piping Butt-Fusion Joint Examination Using Ultrasonic Phased Array

2009 ◽  
Author(s):  
Caleb Frederick ◽  
Allen Porter ◽  
Dave Zimmerman
Keyword(s):  
High Density Polyethylene ◽  
Phased Array ◽  
Low Frequency ◽  
Cold Fusion ◽  
Probability Of Detection ◽  
High Density ◽  
Low Frequency Ultrasound ◽  
Ultrasonic Phased Array ◽  
Joint Examination ◽  
Automated Data Acquisition

With the increasing use of High-Density Polyethylene (HDPE) piping for nuclear applications, nondestructive evaluation is an important tool for evaluation of the integrity in fused joints. This paper will discuss the method of using Ultrasonic Phased Array for inspecting Butt-Fusion (BF) joints in HDPE piping. The benefit of Phased Array is the ability to perform a volumetric inspection using multiple angles which greatly increases the probability of detection of defects, and allows the data to be analyzed using a representative 2-dimentional image of the joint [1]. It has been determined that successfully producing BF joints is highly dependent on environmental and mating-surface conditions. The primary defects of concern are lack-of-fusion (LOF), an area of the joint where there is no bond [2], cold fusion (CF), an area of partial bond, and inclusion. Phased Array has successfully demonstrated the ability of detecting and characterizing these defects using low frequency ultrasound. Factors addressed include joint location, wall thickness, material temperature, transducer wedge material, and manual vs. automated data acquisition.

High-Density Polyethylene Piping Butt-Fusion Joint Examination Using Ultrasonic Phased Array

2010 ◽  
Vol 132 (5) ◽  
Author(s):  
Caleb Frederick ◽  
Allen Porter ◽  
David Zimmerman
Keyword(s):  
High Density Polyethylene ◽  
Phased Array ◽  
Low Frequency ◽  
Cold Fusion ◽  
Probability Of Detection ◽  
High Density ◽  
Two Dimensional Image ◽  
Low Frequency Ultrasound ◽  
Ultrasonic Phased Array ◽  
Joint Examination

With the increasing use of high-density polyethylene (HDPE) piping for nuclear applications, nondestructive evaluation is an important tool for evaluation of the integrity in fused joints. This paper will discuss the method of using ultrasonic phased array for inspecting butt-fusion (BF) joints in HDPE piping. The benefit of phased array is the ability to perform a volumetric inspection using multiple angles, which greatly increases the probability of detection of defects and allows the data to be analyzed using a representative two-dimensional image of the joint. It has been determined that successfully producing BF joints is highly dependent on environmental and mating-surface conditions. The primary defects of concern are lack-of-fusion, an area of the joint where there is no bond, cold fusion, an area of partial bond, and inclusion. Phased array has successfully demonstrated the ability of detecting and characterizing these defects using low frequency ultrasound. Factors addressed include joint location, wall thickness, material temperature, transducer wedge material, and manual versus automated data acquisition.

Optimized Inspection of Thin-Walled Pipe Welds Using Advanced Ultrasonic Techniques

2005 ◽  
Vol 127 (3) ◽  
pp. 237-243 ◽  
Author(s):  
M. G. Lozev ◽  
R. L. Spencer ◽  
D. Hodgkinson
Keyword(s):  
Phased Array ◽  
Ultrasonic Inspection ◽  
Novel Approach ◽  
Array Technology ◽  
Ultrasonic Phased Array ◽  
Thin Walled Pipe ◽  
Ultrasonic Techniques ◽  
Thin Walled ◽  
Planar Fabrication

In this paper an effective way to optimize the inspection of welds in thin-walled pipe less than 6 mm (0.24 in.) thick using automated ultrasonic testing (AUT) is described. AUT offers a better solution than radiography for detecting and sizing of planar defects. However, cap width, weld shrinkage and defect sizing put constraints on the actual ultrasonic approach for inspection of pipes with wall thickness less than 6 mm (0.24 in.). The applications of high-frequency single/multiprobe techniques and phased-array technology for inspection of thin-walled pipe welds have been investigated in this paper. It has been demonstrated that combining an advanced ultrasonic phased-array technique with a novel approach for modeling and simulation of ultrasonic inspection have potentially significant advantages for enhanced detectability, better sizing and improved flaw characterization of randomly oriented planar fabrication imperfections in thin-walled pipe welds.

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