OmniScan MX2 Training Program
OmniScan MX2 Training Program
Phased Array Analysis
Phased Array Analysis
Flaw Depth and Height Sizing
OmniScan MX2 Training – Analysis – Flaw Depth\Height Sizing Cursors
In a typical weld inspection, flaw depth and height sizing is performed on the UT axis
using the A-scan, B-scan, and S-scan.
The three cursors used for flaw depth and height sizing are:
– Data cursor. Used to visualize the A-scan and S-scan at a given position on the scan axis. – UT axis reference cursor. U(r)
– UT axis measure cursor. U(m)
Reference cursor Measure cursor U T ax i s U T ax i s Reference cursor Measure cursor
OmniScan MX2 Training – Flaw Depth\Height Sizing Cursors cont.
How many cursors are available
in the OmniScan MX2 software? A. 13
B. 12 C. 9 D. 6 E. 3
The 3 available cursors are:
– Data cursor. (Blue) – Reference cursor. (Red) – Measure cursor. (Green)
The data cursor appears on the
S-scan, B-scan, and C-scan and is selectable for angle\focal law and scan axis position.
The reference and measure
cursors are linked for the group and available in each axis of each data view (UT, scan, index, and amplitude) and may be turned on or off as desired.
(Display>Overlay>Cursors>Off)
A-scan = UT vs. amplitude axis. S-scan = UT vs. index axis. B-scan = UT vs. scan axis.
C-scan = scan vs. index axis or
OmniScan MX2 Training – Flaw Depth\Height Sizing Cursors cont.
How many total cursors are available in the OmniScan MX2 software?
A. 13 B. 12 C. 9 D. 6 E. 3
OmniScan MX2 Training –Flaw Depth\Height Sizing Readings
The readings associated with flaw depth and height sizing are:
– U(r) Position of the reference cursor on the UT axis. – U(m) Position of the measurement cursor on the UT axis.
– U(m-r) The delta between the UT axis reference and measurement cursor.
In the ID crack example below, the UT axis red reference cursor is placed on the
deepest diffracted crack tip signal (21.39mm) and the green measure cursor on the component ID (25mm).
The U(m-r) reading indicates the through wall dimension of the crack. (3.61mm)
Reference cursor Measure cursor 3 . 6 1 m m
OmniScan MX2 Training –Flaw Depth\Height Sizing Readings cont.
In the example of side wall lack of fusion (SWLF) below, the flaw through wall
dimension or height was determined using a dB drop technique.
The maximum amplitude position was detected on the 53.3 degree focal law at a
depth of 13.58mm.
Using the data cursor or color palette, the reference and measurement the UT axis
cursors are positioned at -3dB of maximum for a through wall dimension of 3.64mm.
Reference cursor
Measure cursor 3.64mm
Different bevel geometry will
result in the need to adjust or adapt the sizing procedure to the application at hand.
-3, -6 or any amplitude drop
technique is dependent on a proper sensitivity calibration and data that is not saturated.
Again, where height sizing of
+\- 1mm is required the use of a supplemental TOFD
OmniScan MX2 Training – Flaw Depth\Height Sizing – Angle Resolution
The ability to both size and characterize flaws is dependent on the on the
inspection strategy with regard to probe frequency, angle resolution (.5, 1, 2 degrees), probe aperture, beam focus (Near field), UT axis point quantity.
This is especially important in a line scan from one index position where the probe
OmniScan MX2 Training – Depth\Height Sizing – Angle Resolution cont.
The two groups below
demonstrate the benefit of a high
element count (32) high
resolution S-scan (.2 degrees),
focused beam.
Both configurations detect the tip
diffracted signals from both
corners of the 1mm X 10mm
deep notch.
The ability to clearly identify the
center of the energy for a
precision measurement is much
improved with the 32 element
high angular resolution group.
5 MHz, 32 X .6mm Focus = 10 .2 degree S-scan5 MHz, 16 X .6mm Focus = 10 1 degree S-scan
OmniScan MX2 Training – Depth\Height Sizing – Angle Resolution cont.
Similarly to the UT and scan axis cursors, the index axis cursors are available for
measurement of individual flaw width or multiple flaw separation.
Relative readings are: I(r), I(m), and I(m-r). (40.21mm-39.21mm = 1mm) In the example below, the ability to measure the width of the notch using the
diffracted corner signals is greatly improved by high element count, high S-scan angle resolution (.2 degrees), and beam focusing at the notch depth.
1mm
10mm
OmniScan MX2 Training – Flaw Depth\Height Sizing – Tip Diffraction
The shear wave dip diffraction technique is commonly used for crack detection and
sizing and is not dependent on amplitude.
Low level signals can indicate crack tips and in greatly assist in precision
measurement, even if not noticeable in the C-scan.
Move the data cursor while visualizing the S-scan and use the UT axis cursor to
establish the deepest detected crack tip. (Pictured below at 7.96mm deep measured from the OD, and 4.54mm as measured from the ID)
OmniScan MX2 Training –– Flaw Depth\Height Sizing U*I(m-r) Reading
When the actual flaw length or diagonal dimension is required as opposed to its
length and height relative to the pipe surface, scan, or UT axis, it is measured using the U*I(m-r) reading as pictured below.
U(m-r) = 7.41mm
U*I(m-r) = 9.25mm
OmniScan MX2 Training – Flaw Depth\Height Sizing – A-scan Envelope
Saving the MX2 data file with the A-scan envelope enabled assists in peaking crack
tips for precision measurement.
Visualize the UT axis reference cursor in the S-scan positioned at 12.42mm while
manipulating the data cursor on the scan axis. Find the deepest tip signal that can clearly be differentiated from background noise.
With the focal law displayed on the A-scan (60.5 degrees), peak the signal using the
envelope and measure with the cursor in the center of the energy. (12.42mm below)
Measure the center of the
energy at the peaked position.
Do not attempt to read the
scales. Use gate readings and cursors for precision
measurements and flaw reporting.
OmniScan MX2 Training – Flaw Depth\Height Sizing – ID Creeping Wave
In the example below, a phased array version of a WSY creeping wave inspection
was performed with a 55-72 degree S-scan on the clock (No encoder) for depth and height sizing of an ID connected crack.
Scan axis clock scan
The 70 L-wave is peaked at
7.77mm in gate B for the through wall dimension of the deepest crack tip. (DB reading)
CE1 (Collateral echo 1) is the mode
converted shear wave signal (30-70-70) that is skipping into the crack on the second leg.
CE2 (Collateral echo 2) when
present indicates that the crack is connected to the inner surface.
Precision wedge delay calibration is
necessary for precision crack tip measurement.
L-wave
Crack tip signals L-wave crack tip signal
CE1
CE2
10L32-A1 probe SA1N60L wedge KK WSY and Panametrics CTS
OmniScan MX2 Training – Analysis – Flaw Depth\Height Sizing cont.
Similarly to length sizing, where precision depth and height sizing is required, use
of TOFD to compliment amplitude based phased array inspections is extremely helpful when the probe cannot be skewed and repositioned for signal
