Ultrasonic Testing Of Welded Joints Research Articles

Development of a technique for applying pa and tofd methods for mechanized ultrasonic testing of welded joints of main pipelines using the USD-60FR-16/128 flaw detector

A technique was developed and tested for selecting beam steering and focusing methods for mechanized ultrasonic testing of circumferential welds of pipelines up to 16 mm thick using phased antenna arrays. Criteria for the identification and interpretation of defects on the time-of-flight diffraction scans in the form of an atlas of defects were developed. The study was carried out using a new domestic flaw detector USD-60FR-16/128.

Weld defects and automation of methods for their detection

The article analyzes the process of electric arc welding. We identified the main types and causes of defects in welded joints and analyzed their main non-destructive testing methods. We show the advantages and disadvantages of each method. The method of ultrasonic control is considered in sufficient detail. We show the advantages of ultrasonic testing of welded joints with a flaw detector with antenna arrays on a practical example. The advantages of this method make it widely used to control the quality of welded seams. We considered peculiarities of application of the “USD-soft” PC program, which allows one to automate the control of welded seams. We found out that it is most effective to carry out automated ultrasonic testing in combination with other types of testing. Automated control, which makes it possible to quickly process the information received at the object of research, allows one to save time and immediately start repair work at the object.

SOME ASPECTS OF NON-DESTRUCTIVE TESTING OF EQUIPMENT AND PIPELINES OF NUCLEAR POWER PLANTS

Topical aspects of non-destructive testing (NDT) of equipment and pipelines of power units of nuclear power plants (NPP) are considered. Non-destructive testing is an integral part of the entire life cycle of a nuclear power plant. Briefly analyzed documentation and types of non-destructive testing at the stage of manufacturing equipment and pipelines. Power of ultrasonic testing of welded joints of pipelines with a thickness of 2 to 6 mm. The main points of drawing up technological maps of non-destructive testing are noted. A brief analysis of the application of non-destructive testing in accordance with the requirements of the regulatory documents of the Russian Federation and the safety standards of the International Atomic Energy Agency is provided. It is shown that in recent years there has been a tendency to expand the role of NDTs from the classical approach of detecting and assessing defects to the use of NDTs in the study of metal degradation and ageing processes during the operation of NPP equipment and pipelines.

IDENTIFICATION AND RELIABILITY OF CONTROL IN ULTRASONIC FLAW DETECTION AND DEFECTOMETRY

The effectiveness of methods and means of ultrasonic non-destructive control (ultrasonic control) is evaluated by the probability of detecting defects and the reliability of the results of the control. In this work, we reserch the behavior of PoD(a) – the defect detection function, which describes the dependence of the probability of detection of defects on their height, and estimates the reliability of control by means of ROC analysis of the control data. An analysis of the PoD curves obtained by ultrasonic testing with ultrasonic flaw detection and ultrasonic flaw detection instruments demonstrates significantly greater reliability of the use of defectometry techniques and devices. ROC curves constructed using ultrasonic defectometry data make it possible to evaluate the reliability of control of defects of various heights. Analysis of ROC curves provides additional information for optimizing ultrasonic control techniques. The studies were carried out on the data array of ultrasonic testing of welded joints with real cracks.

Опыт применения дефектоскопа A1550 IntroVisor при контроле нестандартного сварного соединения

The purpose of article is the measurement of the actual sizes, not the equivalent, of the reflectors at ultrasonic testing of welded joints by flaw detector A1550 IntroVisor.

Justification of rejection values of defect characteristics in ultrasonic testing of welded joints

Probabilistic models of substantiation of rejection values of the measured characteristics of defects during ultrasonic testing of welded joints using phased antenna arrays that reduce possible test errors are considered. It is shown that the most important for usage are the reliability indicators of non-destructive testing, taking into account the sub-rejection. The recommended application areas for evaluating the reliability D* criteria of ultrasonic testing using alternative and quantitative indicators for selecting rejection values of measured defect characteristics have been determined.

A review of international (ISO) and European (EN) standards for the ultrasonic testing of welded joints

A review is presented of modern ISO and EN standards for the ultrasonic testing of welded joints. Special attention is paid to practical implementation of standard requirements that concern setting flaw-detector sensitivity and quality assessment based on the results of ultrasonic testing.

Some special features of using DGS (AVG) diagrams during ultrasonic testing of welded joints

The results of development of a method and piezoelectric probes with DGS (AVG) diagrams for ultrasonic testing devices are considered. The technique is compatible with European standards for ultrasonic testing of welded joints as regards the parameters of piezoelectric probes and sensitivity tuning taking into account damping of elastic waves. The succession of operations in tuning of devices, ultrasonic testing, and evaluation of the results with DGS (AVG) diagrams is considered.

Choosing the parameters of transducers during ultrasonic testing of welded joints by the tandem technique

Formulas for acoustic channels of ultrasonic testing of products by the tandem method have been obtained and numerically studied for strip-and flat-bottom-type flaws. The choice of optimal parameters for a root-tandem transducer for inspecting the unit of welding of a collector to a ПГВ-1000 steam generator of the ВВЭР-1000 reactor is substantiated.

Modern approaches to the certification of ultrasonic testing techniques

Algorithms intended for certifying ultrasonic testing techniques and based on the complex application of reliability and accuracy indices, which are constructed taking into account the character of techniques, specific features of their use, and the objectives of their certification (comparison of techniques, introduction of a new technique involving measurement procedures, etc.) are proposed. On the basis of the main regulations of GOST (State Standard) R ISO 5725-1, 5725-2, the reproducibility and repeatability of determining the measured characteristics of artificial reflectors and actual flaws and the reliability of ultrasonic testing of welded joints have been assessed.

Cluster analysis of results of ultrasonic testing

The methods of cluster and correlation analysis are employed to solve various problems related to the processing of results obtained using the computerized ultrasonic testing of welded joints. In particular, the principal component analysis, K-means algorithm, and support vector machine are considered. A detailed analysis of the methods and the main results are presented.

Data-processing algorithms for automatic operation of ultrasonic systems with coherent data processing

Two algorithms for the automatic determination of flaw parameters during ultrasonic testing of welded joints with a high level of structural background noises are considered. The experimental data collected in the course of automated ultrasonic testing (AUT) using Avgur series with coherent processing of data (Avgur 4.2 and Avgur 5 systems) and the results of the assessment of nondestructive testing data are used. The first algorithm is used to identify zones where flaws may be located. This algorithm is applied after running AUT in the “search” mode. If the parameters of the algorithm application are selected properly, this algorithm makes it possible to determine the coordinates and the conventional length of the identified flaws. The second processing algorithm is intended to determine the flaw’s actual length and height. For its operations the algorithm uses the images obtained from coherent data processing. Results of testing methods for automatic (computer) determination of flaw parameters are cited. These results are obtained by the Avgur system during testing of austenite welded joints in stainless-steel pipes with a diameter of 325 mm and in perlite-steel pipes of various diameters.

A new technique for the identification of ultrasonic flaw signals using deconvolution

The identification of ultrasonic flaw signals is a difficult task in the angle beam ultrasonic testing of welded joints due to the presence of non-relevant signals from the geometric reflectors such as weld-roots and counter-bores. This paper describes a new approach to identify ultrasonic flaw signals in such a problematic situation. A similarity function is defined as the deconvolution of a target signal by a reference signal. The similarity functions for the same type of flaws/references are symmetric bandlimited impulse-like patterns with larger amplitudes while those for different types of flaws/references are asymmetrical broad patterns with relatively smaller amplitudes. Therefore, ultrasonic signals could be identified by the pattern of the similarity function. In the initial experiments, the proposed technique showed great potential for identifying ultrasonic flaw signals in the inspection of weld joints.

Comparison between European and Russian Standards for Ultrasonic Tests of Welded Joints

European standards EN 1712, EN 1713, and EN 1714 for ultrasonic testing and evaluation of welded joints are analyzed. The standards are compared to the Russian acting standard GOST 14782 and the main regulating documents issued by the government's departments.

A poor substitute

The notch is a commonly used type of fabricated flaw in ultrasonic testing of welded joints of small and intermediate thicknesses. The tale is about how some experts attempted inconsiderately to do without it and what resulted from this.

Ultrasonic testing of welded joints in pipelines. New techniques and instruments

The paper describes a technique for ultrasonic testing of welded joints in pipelines of small diameters (10 to 530 mm) with thin walls (2 to 10 mm). A highly efficient technique of ultrasonic testing using “chord” transducers with elastic protective covers in combination with general-or special-purpose flaw indicators is suggested. The technique has been practically tested for several years. Possibility of recording results of ultrasonic tests with the help of specialized portable instruments is discussed. Results of practical utilization of the developed techniques and instruments in detecting real defects are given.