Este trabalho buscou avaliar a técnica ultrassônica de Tempo de Voo da Onda Difratada (TOFD - Time-Of-Flight-Diffraction) para o monitoramento de trincas de fadiga nucleadas no interior de tubos de aço Superdúplex. Para isso, foram fabricados corpos de prova do tipo single edge bending SE(B) a partir de um tubo de aço Superdúplex sem costura. Estas amostras foram ensaiadas em fadiga, e o crescimento de trinca foi monitorado com as técnicas de TOFD, de Flexibilidade no Descarregamento (Compliance) – durante os ensaios, foram dadas sobrecargas mecânicas que causaram deformação plástica. As deformações serviram de pontos de referência para analisar o crescimento de trinca. Para aferir a validade os resultados obtidos com o TOFD nos ensaios de fadiga e fazer uma correlação com o monitoramento em campo de defeitos em tubos de aço Superdúplex, foi fabricado um padrão que simulou um tubo com defeito interno conhecido. Este padrão foi inspecionado com o TOFD, empregando os mesmos equipamentos e parâmetros utilizados nos ensaios de fadiga. Foi possível monitorar o crescimento de trinca em fadiga utilizando a técnica de TOFD e houve forte correlação entre os dados obtidos com o TOFD e o Compliance. A inspeção no tubo padrão manteve uma diferença entre a medida real e a obtida com o TOFD proporcional às encontradas durante o monitoramento dos ensaios de fadiga. / This study aimed to evaluate the ultrasonic technique Time-Of-Flight-Diffraction (TOFD) in monitoring fatigue nucleated cracks within super duplex steel pipes. In order to do it, single edge bending SE (B) specimens were manufactured using a super duplex steel seamless pipe. These samples were tested in fatigue and crack growth was monitored with two different techniques: TOFD and Flexibility in Unloading (Compliance). During the tests, it was used mechanical overloadings so deformation would be cause on the steel pipes. The deformations caused by that served as reference points to analyze the cracking growth. Thus, to assess the validity of the data obtained with the TOFD in fatigue tests, it was made a pattern that simulated a tube with known internal defect. This pattern was inspected with the TOFD, using the same equipment and parameters used in the fatigue tests. A correlation with the monitoring of defects field super duplex steel pipes was also made. The experiment has shown it is possible to monitor the cracking growth fatigue using the TOFD technique. Figures indicate, as well, there is a strong correlation between results obtained with the TOFD and Compliance. The inspection of the standard steel pipe maintained a difference between the actual measurement and obtained measurement. That difference was proportional from TOFD data and those found during the monitoring of the fatigue tests.

Este trabalho buscou avaliar a técnica ultrassônica de Tempo de Voo da Onda Difratada (TOFD - Time-Of-Flight-Diffraction) para o monitoramento de trincas de fadiga nucleadas no interior de tubos de aço Superdúplex. Para isso, foram fabricados corpos de prova do tipo single edge bending SE(B) a partir de um tubo de aço Superdúplex sem costura. Estas amostras foram ensaiadas em fadiga, e o crescimento de trinca foi monitorado com as técnicas de TOFD, de Flexibilidade no Descarregamento (Compliance) – durante os ensaios, foram dadas sobrecargas mecânicas que causaram deformação plástica. As deformações serviram de pontos de referência para analisar o crescimento de trinca. Para aferir a validade os resultados obtidos com o TOFD nos ensaios de fadiga e fazer uma correlação com o monitoramento em campo de defeitos em tubos de aço Superdúplex, foi fabricado um padrão que simulou um tubo com defeito interno conhecido. Este padrão foi inspecionado com o TOFD, empregando os mesmos equipamentos e parâmetros utilizados nos ensaios de fadiga. Foi possível monitorar o crescimento de trinca em fadiga utilizando a técnica de TOFD e houve forte correlação entre os dados obtidos com o TOFD e o Compliance. A inspeção no tubo padrão manteve uma diferença entre a medida real e a obtida com o TOFD proporcional às encontradas durante o monitoramento dos ensaios de fadiga. / This study aimed to evaluate the ultrasonic technique Time-Of-Flight-Diffraction (TOFD) in monitoring fatigue nucleated cracks within super duplex steel pipes. In order to do it, single edge bending SE (B) specimens were manufactured using a super duplex steel seamless pipe. These samples were tested in fatigue and crack growth was monitored with two different techniques: TOFD and Flexibility in Unloading (Compliance). During the tests, it was used mechanical overloadings so deformation would be cause on the steel pipes. The deformations caused by that served as reference points to analyze the cracking growth. Thus, to assess the validity of the data obtained with the TOFD in fatigue tests, it was made a pattern that simulated a tube with known internal defect. This pattern was inspected with the TOFD, using the same equipment and parameters used in the fatigue tests. A correlation with the monitoring of defects field super duplex steel pipes was also made. The experiment has shown it is possible to monitor the cracking growth fatigue using the TOFD technique. Figures indicate, as well, there is a strong correlation between results obtained with the TOFD and Compliance. The inspection of the standard steel pipe maintained a difference between the actual measurement and obtained measurement. That difference was proportional from TOFD data and those found during the monitoring of the fatigue tests.

Este trabalho buscou avaliar a técnica ultrassônica de Tempo de Voo da Onda Difratada (TOFD - Time-Of-Flight-Diffraction) para o monitoramento de trincas de fadiga nucleadas no interior de tubos de aço Superdúplex. Para isso, foram fabricados corpos de prova do tipo single edge bending SE(B) a partir de um tubo de aço Superdúplex sem costura. Estas amostras foram ensaiadas em fadiga, e o crescimento de trinca foi monitorado com as técnicas de TOFD, de Flexibilidade no Descarregamento (Compliance) – durante os ensaios, foram dadas sobrecargas mecânicas que causaram deformação plástica. As deformações serviram de pontos de referência para analisar o crescimento de trinca. Para aferir a validade os resultados obtidos com o TOFD nos ensaios de fadiga e fazer uma correlação com o monitoramento em campo de defeitos em tubos de aço Superdúplex, foi fabricado um padrão que simulou um tubo com defeito interno conhecido. Este padrão foi inspecionado com o TOFD, empregando os mesmos equipamentos e parâmetros utilizados nos ensaios de fadiga. Foi possível monitorar o crescimento de trinca em fadiga utilizando a técnica de TOFD e houve forte correlação entre os dados obtidos com o TOFD e o Compliance. A inspeção no tubo padrão manteve uma diferença entre a medida real e a obtida com o TOFD proporcional às encontradas durante o monitoramento dos ensaios de fadiga. / This study aimed to evaluate the ultrasonic technique Time-Of-Flight-Diffraction (TOFD) in monitoring fatigue nucleated cracks within super duplex steel pipes. In order to do it, single edge bending SE (B) specimens were manufactured using a super duplex steel seamless pipe. These samples were tested in fatigue and crack growth was monitored with two different techniques: TOFD and Flexibility in Unloading (Compliance). During the tests, it was used mechanical overloadings so deformation would be cause on the steel pipes. The deformations caused by that served as reference points to analyze the cracking growth. Thus, to assess the validity of the data obtained with the TOFD in fatigue tests, it was made a pattern that simulated a tube with known internal defect. This pattern was inspected with the TOFD, using the same equipment and parameters used in the fatigue tests. A correlation with the monitoring of defects field super duplex steel pipes was also made. The experiment has shown it is possible to monitor the cracking growth fatigue using the TOFD technique. Figures indicate, as well, there is a strong correlation between results obtained with the TOFD and Compliance. The inspection of the standard steel pipe maintained a difference between the actual measurement and obtained measurement. That difference was proportional from TOFD data and those found during the monitoring of the fatigue tests.

L’onde de tête est l’onde de première arrivée observée au cours d’une inspection TOFD (Time Of Flight Diffraction). La technique TOFD est une méthode d’inspection très répandue en CND (Contrôle Non Destructif) par ultrasons, faisant appel à deux capteurs piézoélectriques positionnés symétriquement et en vis-à-vis, avec un écartement constant, au-dessus de la surface d’entrée de la pièce à inspecter.Une étude numérique montre que la propagation de l’onde de tête près d’une surface d’entrée irrégulière n’est plus un phénomène de propagation uniquement surfacique comme dans le cas d’une surface plane, mais fait aussi intervenir un phénomène de propagation volumique induit par des diffractions du champ ultrasonore sur les irrégularités de surface.Pour modéliser ces phénomènes, une méthode générique de tracé de rayons fondée sur le principe de Fermat généralisé est développée et détermine le parcours effectif dans une pièce de surface irrégulière de toutes les ondes ultrasonores se propageant dont l’onde de tête.L’évaluation des phénomènes de diffraction par des modèles d’amplitude suivant une approche rayons permet ensuite d’obtenir une simulation complète (temps de vol, front d’onde et amplitude) de l’onde de tête pour plusieurs types d’irrégularités surfaciques. Des validations théoriques et expérimentales de l’outil de simulation développé ont été effectuées et se sont avérées concluantes. / The head wave is the first arrival wave received during a TOFD (Time Of Flight Diffraction) inspection. The TOFD technique is a classical ultrasonic NDT (Non Destructive Testing) inspection method employing two piezoelectric transducers which are symmetrically placed facing each other with a constant spacing above the inspected specimen surface.The head wave propagation along an irregular entry surface is shown by a numerical study to be not only a surface propagation phenomenon, as for the plane surface case, but also involves a bulk propagation phenomenon caused by diffractions of the ultrasonic wave field on the surface irregularities.In order to model theses phenomena, a generic ray tracing method based on the generalized Fermat’s principle has been developed and establishes the effective path of any ultrasonic propagating wave in a specimen of irregular surface, notably including the effective head wave path.The diffraction phenomena evaluation by amplitude models using a ray approach allows to provide a complete simulation (time of flight, wave front and amplitude) of the head wave for numerous kinds of surface irregularity. Theoretical and experimental validations of the developed simulation tool have been carried out and have proven successful.

AgÃncia Nacional do PetrÃleo / O presente trabalho tem como objetivo caracterizar diferentes defeitos de soldagem ( falta de fusÃo, falta de penetraÃÃo e porosidade) inseridos em corpos de prova durante o processo de soldagem, atravÃs da anÃlise fractal di sinais ultra-sÃnicos obtidos pela tÃcnica TOFD. Para eliminar os ruÃdos, os sinais foram tratados usando dois mÃtodos de filtragem, passa banda e Savitzky-Golay. Na anÃlise fractal dos sinais foram utilizados trÃs mÃtodos: anÃlise de Hurst, anÃlise de flutuaÃÃo sem tendÃncias e anÃlise de cobertura mÃnima. Nos trÃs mÃtodos foram considerados sinais filtrados isoladamente, bem como sinais filtrados concatenados. Os parÃmetros caracterÃsticos das regiÃes de escala, para cada tipo de anÃlise, foram calculados atravÃs de regressÃes lineares, sendo tambÃm determinado o desvio padrÃo de cada sinal. A caracterizaÃÃo de todos os defeitos foi determinada atravÃs dos parÃmetros obtidos para os sinais filtrados pelo mÃtodo Savitzky-Golay e para os sinais concatenados filtrados pelo mÃtodo passa banda. Foi tambÃm mostrado que, no contexto dessa anÃlise fractal, a melhor discriminaÃÃo foi obtida utilizando o mÃtodo de Savitzky-Golay. / The present work aims to characterize different welding defects (lack of fusion, lack of penetration and porosity) inserted into the specimens during the welding process by analyzing fractal di ultrasonic signals obtained by the TOFD technique. To eliminate the noise, the signals were processed using two methods of filtering, band pass and Savitzky-Golay. In fractal analysis of signals using three methods: analysis of Hurst analysis, trends and fluctuation analysis without minimum coverage. In the three methods were individually filtered signals and filtered signals concatenated. The characteristic parameters of the regions of scale, for each type of analysis were calculated by linear regression, and is also given the standard deviation of each signal. The characterization of all defects was determined by the parameters obtained for the signals filtered by the method Savitzky-Golay and concatenated signals filtered by bandpass method. It was also shown that in the context of this fractal analysis, the best discrimination was achieved using the method Savitzky-Golay.

In this thesis, two ultrasonic timing methods are used in order to investigate the accuracy and reliability of measurements for surface breaking cracks having different orientations and heights. Also the best applicable measurement technique is searched by comparing the received test results. These methods are the Time of Flight Diffraction (TOFD) Method using diffraction of longitudinal waves and another method using the reflection of shear waves from the crack tips. In order to simulate and measure the height of surface breaking cracks three sets of test blocks from steel, and two sets of wedges from plexiglas material are manufactured. Also several probes having frequencies of 2Mhz, 4Mhz, 5Mhz and angles of 45o and 70o are used. Some test procedures are created to make realistic comparisons between the test results and the ones found by previous studies in literature. The results are compared according to the standard deviations of errors in crack height measurements and it is found that the depth, orientation of defects and the frequency of probes have considerable affect on the results. With wider probe angles and higher frequencies of probes to some extent the errors are observed to be running low and the height of cracks could be measured closer to the original size. The amount of the errors is increased in measurements with the increasing angle of cracks. The results of both methods are found to be very satisfactory. A range of &plusmn / 0.5 mm for means of error from the original vertical crack heights is determined. The results agree with the previous studies.

L'onde de tête est l'onde de première arrivée observée au cours d'une inspection TOFD (Time Of Flight Diffraction). La technique TOFD est une méthode d'inspection très répandue en CND (Contrôle Non Destructif) par ultrasons, faisant appel à deux capteurs piézoélectriques positionnés symétriquement et en vis-à-vis, avec un écartement constant, au-dessus de la surface d'entrée de la pièce à inspecter. Une étude numérique montre que la propagation de l'onde de tête près d'une surface d'entrée irrégulière n'est plus un phénomène de propagation uniquement surfacique comme dans le cas d'une surface plane, mais fait aussi intervenir un phénomène de propagation volumique induit par des diffractions du champ ultrasonore sur les irrégularités de surface. Pour modéliser ces phénomènes, une méthode générique de tracé de rayons fondée sur le principe de Fermat généralisé est développée et détermine le parcours effectif dans une pièce de surface irrégulière de toutes les ondes ultrasonores se propageant dont l'onde de tête. L'évaluation des phénomènes de diffraction par des modèles d'amplitude suivant une approche rayons permet ensuite d'obtenir une simulation complète (temps de vol, front d'onde et amplitude) de l'onde de tête pour plusieurs types d'irrégularités surfaciques. Des validations théoriques et expérimentales de l'outil de simulation développé ont été effectuées et se sont avérées concluantes.

Present and future demonstrator designs were used to demonstrate the quality assurance of welds. The NDT methods tested on prototype demonstrator parts are: visual inspection, radius gauges, throat size gauge, liquid-penetrant testing, magnetic particle testing and ultrasonics with pulse echo and phased array. The other methods like eddy current, time of flight diffraction, radiography, impression test, macro test and infrared thermographs are currently being analyzed along with their inspection costs.   The control plans for present and future designs with corresponding present and future NDT methods are suggested to minimize a shift in process. Magnetic particle testing revealed a lack of fusion and cracks for fillet welds, whereas ultrasonic pulse echo and phased array identified an internal lack of fusion, inner pores/slag inclusions on butt welds. Ultrasonic PAUT & TOFD could be used for accurate defect identification and thermography for online identification of lack of penetration, depth of penetration and weld parameters. / Weight reduction by improved weld quality (WIQ)

<p>I både kvalitets- och kontrollarbete finns det behov att kunskapsmässigt komma så nära verkligheten som möjligt vid fastställande av defektparametrar för oförstörande provning (OFP). Orsaken är att olika acceptanskrav och bedömningsgränser är svåra att klarlägga när man inte kan förlita sig på att uppgifter är realistiska. I projektet har olika erfarenheter använts för att få en bättre helhetsbild i området för defektparametrar och oförstörande provning.</p><p>Denna rapport redovisar den inledande delen av forskning och utvecklingsprojektet PLANT 2, där olika defektparametrar kartlagts och en teoretisk bedömning utförts med avseende på hur signalsvaret påverkas för OFP-metoderna virvelström (ET) och ultraljudsprovning (UT) i form av puls-eko (PE) och ”time-of-flight-diffraction” (TOFD).</p><p>Definitionen av redovisade defektparametrar följer i stort SKI-rapport 95:70 [1]. Defektparametrar i denna rapport redovisas i bilaga 1.</p><p>Vid bedömningen av defektparametrarnas inverkan på OFP-tekniker, har drift¬inducerande defekter och tillverkningsdefekter hanterats separat. För de driftinducerande defekterna delades bedömningen upp i en generell och en specifik bedömning. De defektparametrar som bedöms specifikt och klassats att påverka signalsvaret betydligt bör vara av mest intresse i nästkommande etapp. Följande defektparametrar bedömdes påverka signalsvaret betydligt:</p><p>• Form i ytan, antal sprickor och avstånd i gatstensmönster</p><p>(vid termisk ut¬mattning)</p><p>• Form i djupled</p><p>• Sprickbredd vid sprickspets och sprickspetsradie</p><p>För tillverkningsdefekter bedömdes defektparametrarnas form i djupled och geometri påverka signalsvaret betydligt för defekttyperna slagg och bindfel.</p><p>Vid utvärdering av UT-PE och UT-TOFD teknikerna överensstämde resultatet helt med den teoretiska bedömningen. För ET-tekniken stämde endast en av tre defektparametrar överens med den teoretiska bedömningen.</p> / <p>In quality control of defect parameters for Non-Destructive Testing (NDT) it’s essential to have good knowledge about the defects. The reason is that different acceptance criteria and assessments must be based on defects that correspond to real defects. In this project different experience has been analyzed to get a better overview between defect parameters and non-destructive testing.</p><p>This report shows the beginning of the research & development project PLANT 2. There are different flaw parameters that have been mapped and a theoretical assessment has been performed with regard to how the signal response is influenced by the NDT techniques eddy current, ultrasonic pulse echo and ultrasonic time-of-flight-diffraction.</p><p>The definition of the reported flaw parameters does in general follow the one presented in SKI-report 95:70 [1]. The actual flaw parameters in this report are presented in appendix 1.</p><p>In the assessment of the influences on the NDT techniques with regard to flaw parameters, service-induced flaws and manufactured flaws have been separated in to two categories. The service-induced flaws have further on been separated in a general and a specific assessment. Those flaw parameters that have been assessed to be specific and classified to influence the signal response considerably should be the ones of most interest in future studies. The following flaw parameters were assessed to affect the signal response considerably:</p><p>• Macroscopic shape in the surface direction, number of cracks</p><p>and cobblestone stone pattern distance (for thermal fatigue)</p><p>• Macroscopic shape in the through thickness direction</p><p>• Crack width at the crack tip and the crack tip radius</p><p>For flaws caused by the manufacturing process, type slag and lack of fusion, the flaw parameters “Macroscopic shape in the through thickness direction” and “the geometry” were influenced by the signal response considerably.</p><p>In the evaluation of signal response with the UT pulse echo and UT TOFD techniques, the result corresponded to the theoretical assessment. For the eddy current technique only one of three flaw parameters corresponded to the theoretical assessment.</p>

I både kvalitets- och kontrollarbete finns det behov att kunskapsmässigt komma så nära verkligheten som möjligt vid fastställande av defektparametrar för oförstörande provning (OFP). Orsaken är att olika acceptanskrav och bedömningsgränser är svåra att klarlägga när man inte kan förlita sig på att uppgifter är realistiska. I projektet har olika erfarenheter använts för att få en bättre helhetsbild i området för defektparametrar och oförstörande provning. Denna rapport redovisar den inledande delen av forskning och utvecklingsprojektet PLANT 2, där olika defektparametrar kartlagts och en teoretisk bedömning utförts med avseende på hur signalsvaret påverkas för OFP-metoderna virvelström (ET) och ultraljudsprovning (UT) i form av puls-eko (PE) och ”time-of-flight-diffraction” (TOFD). Definitionen av redovisade defektparametrar följer i stort SKI-rapport 95:70 [1]. Defektparametrar i denna rapport redovisas i bilaga 1. Vid bedömningen av defektparametrarnas inverkan på OFP-tekniker, har drift¬inducerande defekter och tillverkningsdefekter hanterats separat. För de driftinducerande defekterna delades bedömningen upp i en generell och en specifik bedömning. De defektparametrar som bedöms specifikt och klassats att påverka signalsvaret betydligt bör vara av mest intresse i nästkommande etapp. Följande defektparametrar bedömdes påverka signalsvaret betydligt: • Form i ytan, antal sprickor och avstånd i gatstensmönster (vid termisk ut¬mattning) • Form i djupled • Sprickbredd vid sprickspets och sprickspetsradie För tillverkningsdefekter bedömdes defektparametrarnas form i djupled och geometri påverka signalsvaret betydligt för defekttyperna slagg och bindfel. Vid utvärdering av UT-PE och UT-TOFD teknikerna överensstämde resultatet helt med den teoretiska bedömningen. För ET-tekniken stämde endast en av tre defektparametrar överens med den teoretiska bedömningen. / In quality control of defect parameters for Non-Destructive Testing (NDT) it’s essential to have good knowledge about the defects. The reason is that different acceptance criteria and assessments must be based on defects that correspond to real defects. In this project different experience has been analyzed to get a better overview between defect parameters and non-destructive testing. This report shows the beginning of the research &amp; development project PLANT 2. There are different flaw parameters that have been mapped and a theoretical assessment has been performed with regard to how the signal response is influenced by the NDT techniques eddy current, ultrasonic pulse echo and ultrasonic time-of-flight-diffraction. The definition of the reported flaw parameters does in general follow the one presented in SKI-report 95:70 [1]. The actual flaw parameters in this report are presented in appendix 1. In the assessment of the influences on the NDT techniques with regard to flaw parameters, service-induced flaws and manufactured flaws have been separated in to two categories. The service-induced flaws have further on been separated in a general and a specific assessment. Those flaw parameters that have been assessed to be specific and classified to influence the signal response considerably should be the ones of most interest in future studies. The following flaw parameters were assessed to affect the signal response considerably: • Macroscopic shape in the surface direction, number of cracks and cobblestone stone pattern distance (for thermal fatigue) • Macroscopic shape in the through thickness direction • Crack width at the crack tip and the crack tip radius For flaws caused by the manufacturing process, type slag and lack of fusion, the flaw parameters “Macroscopic shape in the through thickness direction” and “the geometry” were influenced by the signal response considerably. In the evaluation of signal response with the UT pulse echo and UT TOFD techniques, the result corresponded to the theoretical assessment. For the eddy current technique only one of three flaw parameters corresponded to the theoretical assessment.