Ultrasonic phased array sound field mapping through large-bore coarse grained cast austenitic stainless steel (CASS) piping materials

2012 ◽  
Author(s):  
A. D. Cinson ◽  
S. L. Crawford ◽  
M. S. Prowant ◽  
A. A. Diaz ◽  
J. E. Hathaway ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Phased Array ◽  
Sound Field ◽  
Coarse Grained ◽  
Field Mapping ◽  
Ultrasonic Phased Array

scholarly journals Phased Array Ultrasonic Sound Field Mapping in Cast Austenitic Stainless Steel

2014 ◽  
Author(s):  
Susan Crawford ◽  
Matthew Prowant ◽  
Anthony Cinson ◽  
Michael Larche ◽  
Aaron Diaz ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Phased Array ◽  
Sound Field ◽  
Field Mapping ◽  
Ultrasonic Sound

Ultrasonic Sound Field Mapping Through Coarse Grained Cast Austenitic Stainless Steel Components

2014 ◽  
Author(s):  
Susan L. Crawford ◽  
Matthew S. Prowant ◽  
Anthony D. Cinson ◽  
Michael R. Larche ◽  
Aaron A. Diaz ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Phased Array ◽  
Flaw Detection ◽  
Sound Field ◽  
Coarse Grained ◽  
Sound Fields ◽  
Fine Grained ◽  
Ultrasonic Sound ◽  
Field Formation

The Pacific Northwest National Laboratory (PNNL) has been involved with nondestructive examination of coarse-grained cast austenitic stainless steel (CASS) components for over 30 years. More recent work has focused on mapping the ultrasonic sound fields generated by low-frequency phased-array probes that are typically used for the evaluation of CASS materials for flaw detection and characterization. The casting process results in the formation of large-grained material microstructures that are nonhomogeneous and anisotropic. The propagation of ultrasonic energy for examination of these materials results in scattering, partitioning, and redirection of these sound fields. The work reported here provides an assessment of sound field formation in these materials and provides recommendations on ultrasonic inspection parameters for flaw detection in CASS components. Confirmatory research conducted at PNNL consisted of acquiring sound field data from four CASS components containing columnar, equiaxed, and banded grain structures, and a fine-grained wrought stainless steel specimen used for benchmarking. Phased-array probes with center frequencies of 0.5, 0.8, and 1.0 MHz were used for sound field formation, with a pinducer being raster scanned over the end of the specimen face to capture the sound field energy. Data were collected at multiple refracted and skew angles, and imaging performed for analyses. A 6.4-mm (0.25-in.) thick slice of material was removed from the end of the CASS components and the beam mapping repeated. This slicing and mapping sequence was performed three times to produce multiple beam images through the specimens. Grain sizes were also measured at each mapped specimen face and compared to sound field characteristics. The acquired sound field images were characterized in terms of beam redirection from the theoretical position, beam scatter or coherence, and partitioning. A comparison of the fine-grained beam data to the CASS data is made and conclusions are presented.

High-selectivity imaging of closed cracks in a coarse-grained stainless steel by nonlinear ultrasonic phased array

2017 ◽  
Vol 91 ◽  
pp. 139-147 ◽  
Author(s):  
Yoshikazu Ohara ◽  
Koji Takahashi ◽  
Yoshihiro Ino ◽  
Kazushi Yamanaka ◽  
Toshihiro Tsuji ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Phased Array ◽  
High Selectivity ◽  
Coarse Grained ◽  
Nonlinear Ultrasonic ◽  
Ultrasonic Phased Array

An Ultrasonic Phased Array Evaluation of Cast Austenitic Stainless Steel Pressurizer Surge Line Piping Welds

2010 ◽  
Author(s):  
Aaron A. Diaz ◽  
Anthony D. Cinson ◽  
Susan L. Crawford ◽  
Traci L. Moran ◽  
Michael T. Anderson
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Ultrasonic Testing ◽  
Phased Array ◽  
Fatigue Cracks ◽  
Ultrasonic Beam ◽  
Custom Made ◽  
Ultrasonic Phased Array ◽  
Surge Line ◽  
Thermal Fatigue Cracks

A set of circumferentially oriented thermal fatigue cracks (TFCs) were implanted into three cast austenitic stainless steel (CASS) pressurizer (PZR) surge-line specimens (pipe-to-elbow welds) that were fabricated using vintage CASS materials formed in the 1970s, and flaw responses from these cracks were used to evaluate detection and sizing performance of the phased-array (PA) ultrasonic testing (UT) methods applied. Four different custom-made PA probes were employed in this study, operating nominally at 800 kHz, 1.0 MHz, 1.5 MHz, and 2.0 MHz center frequencies. The CASS PZR surge-line specimens were polished and chemically etched to bring out the microstructures of both pipe and elbow segments. Additional studies were conducted and documented to address baseline CASS material noise and observe possible ultrasonic beam redirection phenomena.

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