1. Maurício Ogawa4, André Rocha Pimenta5
CNDE 2013 – Le Mans
Technical Evaluation of Ultrasound Phased Array Inspection in Welded Joints of AISI 304L Austenitic Stainless Steel
Ramon Ferreira Ferreira¹, Maurício Saldanha Motta², Lincoln Silva Gomes³,
Maurício Ogawa4, André Rocha Pimenta5

2. Sumary of Presentation
Introduction
Objective
Theoric Review
Methodology
Results and Discussions
Conclusions
Acknowledgements
Contacts

3. Introduction
The mesh of the pipelines in Brazil corresponds a number of 26 thousand miles, data from September 2011, this makes the country the number 16 in the world rankings.
The occurrences of accidents with this transport system have shown the enormous complexity and extension of the damage done not only to companies, but mainly with the ecosystems and the communities around these events.

4. Introduction
Stainless steels are materials with increasing in use at industries, because the good corrosion resistance and mechanical properties. However these materials require special attention to work with them, under the risk of compromising their specific properties.
The ultrasound inspection technique has some difficulties in inspection of components manufactured from austenitic stainless steel castings or welded. But in 10 years ago started to develop the phased array inspection technique for industry (using multi-element transducers), which allows better control of the ultrasonic beam and treatment of received signals.

5. Objective
Developed a study to evaluate the phased array ultrasound technique effects in austenitic welds, and to identify a correlation between microstructure and the ultrasonic properties, to understand the ultrasonic beam behavior, reducing errors of interpretation and to helps the characterization of the defects in inspection.

6. Secondaries Objectives
Analyze the welding parameters and your influence in microstructural changes.
Microstructural analysis in the welded samples.
Hardness measurement.
Scanning electron microscope analysis and EDS, verifying the presence of the ferrite in the austenitic matrix, in the welded samples.
Analyze the percentage of the ferrite and austenite phase’s, in the areas of top, middle and root.
Measure the velocity and ultrasonic attenuation with conventional and phased array technique.
Analyze the influence of the ultrasonic velocity in the sizing of defects.
Correlation with percentage phase’s, hardness, velocity and ultrasonic attenuation.

7. Theoric Review
Base Metal
Weld metal
Base metal
HAZ
Ferrite in spine
Austenitic matrix

8. Theoric Review
(a) C-scan; (b) S-scan; (c) B-scan; (d) A-scan.

9. Methodology Argonium gas
The material used for the manufacture of specimens, in this study, has been austenitic stainless steel AISI 304 l, in tubes with 16 diameter inches, Schedule 30 (thickness, 9.53 mm) with V-Groove, bevel angle of 35°, height of 1 mm nose and opening of 4 mm.
GTAW
Argonium gas

10. Methodology
The list of equipments used for the study.

11. Methodology Some analysis was made to make the correlation study.
Micrograph analysis
Phase’s percentage analysis
SEM and EDS analysis
Hardeness measurement
Velocity and attenuation measurement

12. Results and Discussions
Microstructure results:
CP01 CP02 CP03 CP04
Top, middle, root

13. Results and Discussions
Phase’s percentage analysis:
CP01 CP CP CP04

14. Results and Discussions
Phase’s percentage analysis:

15. Results and Discussions
SEM and EDS Analisys:
Cr Ni
Cr Ni

16. Results and Discussions
Hardness Measurement:
5 kgf (HV5,0)
Vickers diamond pyramid with angle 136°).

17. Results and Discussions
Velocity and Attenuation Measurement:
Velocity
Attenuation

18. Results and Discussions
Correlation with microstructure and ultrasonic properties:
The correlation showed that the ultrasonic speed decrease, and the attenuation increase, when the percentage of ferrite in the microstructure increases. We also observed that the samples with higher percentages of ferrite, had the highest average hardness values, but with few variations.

19. Conclusions
Analysing the consumables, the ER308L formed more ferrite than ER316L in the weld.
The SEM and EDS analysis showed the change of the chrome and nickel percentage, in the analysis of the presence of ferrite in the matrix structure.
The attenuation measurement showed that the values detected by conventional ultrasound and phased array techniques, were higher for samples with higher percentage of ferrite.
The sonic speed is directly proportional to the sizing of discontinuities and thickness measurement.
The correlation showed that the ultrasonic speed decrease, and the attenuation increase, and the average hardness values increase, when the percentage of ferrite in the microstructure increases.
Phased array technique has greater sonic pressure then the conventional technique, increasing the POD.

20. Thank you! Acknowledgements Contacts
To SENAI Welding Technology Centre, CEFET-RJ, IFRJ-Paracambi for the incentive in the research and development projects.
Contacts
MSc. Engineer Ramon Fonseca Ferreira, /
DSc. Lincoln Silva Gomes, /
Manager, Maurício Ogawa, /
Thank you!