Olympus dual matrix array probes
extend the inspection range of the OmniScan and Focus instruments
for coarse grained austenitic stainless steels
and inconel alloy materials and welds.
The dual matrix array or “DMA” probes
improve flaw detection and sizing
of difficult to penetrate materials
by combining the benefits of phased array S-scans
and low frequency transmit-receive
or TRL inspection strategy
DMA probes are purchased in either a dual configuration
for single sided inspection
or quad configuration for two sided simultaneous inspection
with all arrays wired into the same connector
eliminating the need for a splitter.
The Olympus 2.25MHz A17 DMA probe
contains a 4X7 large element configuration in each housing
optimized for thicker and more attenuative austenitic materials.
In this example,
programming a 30-80 degree longitudinal wave S-scan
provides full volumetric inspection of the austenitic weld
in one pass using the Olympus VersaMouse scanner.
The 4MHz A27 DMA probe
uses a 2X16 element configuration in each housing
and is optimized for thinner materials using smaller elements
for improved beam steering and surface inspections.
In this example,
using a wedge optimized for surface and near surface detection,
a 70-85 degree longitudinal wave S-scan
is focused at 20mm in front of the wedge face
where shear wave pulse echo full V skipping is not possible
for shallow and surface connected flaw detection.
For high angle surface testing
the OmniScan display is configured for an uncorrected S-scan
to optimize the display size
and the gate is positioned to represent the width
of the inspection area over the weld in the C-scan
for detection of surface and near surface flaws.
The DMA wedges are available
in either flat or AOD configuration
contoured for the pipe diameter.
Acoustically insulating the transmitter and receiver in the wedge
eliminates the need for wedge dampening material
and a large standoff that is required
in longitudinal pulse echo wedges.
resulting in more energy and less noise in the inspection data.
DMA probe wedges are removable,
come with scanner and irrigation ports,
and are designed for either volumetric
or shallow surface inspection
similar to conventional UT TRL creeping wave probes.
The 32:128PR module
supports up two DMA probes
for two sided simultaneous phased array inspection.
Instrumentation to drive DMA probes
requires the ability to transmit and receive
using different elements or apertures
available in the OmniScan and Focus instruments
with the pulser-receiver or “PR” option.
upgrade pricing is available for standard
or previous generation OmniScan modules.
Improvements in latest generation PA2 OmniScan modules
includes expanded operating temperatures,
fanless design,
115V pulser,
video filtering,
, and significantly improved signal to noise ratio,
required for austenitic inspections.
Standard OmniScan software supports DMA probes
and requires a law file import
from either the Olympus Setup Builder,
Tomoview calculator,
or library of pre-defined law files for S-scan configuration
to include angular range and focus.
UT optimization and calibration functions
are performed using austenitic reference standards or pipe samples
The attenuation of the material and size of weld bevel
will determine the number of line scans or focus strategies
required to meet the needs of the inspection.
Detection and sizing accuracy limits
for any material or weld bevel is dependent on many factors
including the probe frequency capable of detection
and can only be determined through trial and error
on weld samples or reference blocks of the same material.
DMA probes are only recommended
for materials and weld bevels
where shear wave pulse echo inspection is not possible.
For manual encoded inspection
a chain scanner using a single DMA probe
performs line scans on an inconel CRA weld for detection.
After a flaw is detected,
use of the index raster arm allows the probe
to be repositioned for sizing optimization.
A two axis mechanized scanner
provides full automated inspection of CRA welds
to include one line scans for detection
and raster scanning for improved flaw sizing and characterization.
OmniPC allows Omniscan data to be analyzed on a computer
with the same software interface as the instrument.
In this example, a 2Mhz A17 DMA probe
detects ID connected thermal fatigue cracking
in the heat affected zone of an inconel weld and base material.
the crack is length sized on the C-scan
and depth and height sized on the A-scan, B-scan, and S-scans.
Use of Tomoview for analysis or acquisition
provides custom display configuration,
more C-scan functionality,
and the abilitiy to merge multiple groups
and\or multiple data files together for simultaneous analysis.
More than software features or instrument specifications,
improvements in austenitic weld inspection will be realized
by probe technology and wedge strategies.
Olympus matrix arrays are one more application
that expands the range of what is possible with an OmniScan
and allows rapid development and qualification
at the inspector level using standard catalog products.
For more information on Olympus Dual Matrix Array Probes
and austenitic weld inspection
contact your local representative
or visit us online at www.olympus-ims.com