OmniScan SX \ MX2 Training ProgramPhased Array Wedges Chris Magruder V4.1B2T9 OmniScan SX \ MX2 Training – Phased Array Wedges Overview Phased array wedges perform the same function as conventional UT wedges by coupling sound energy from the probe to the material at the desired refracted angle and wave type. Phased array wedges come in all shapes and sizes for various applications and are an essential part of the inspection process. Phased array wedges are used to assist the probe in beam formation for shear wave and longitudinal wave inspections, just like UT. 1D Wedges typically used in OmniScan MX2 applications come in 3 varieties: 1. Shear wave angle beam 2. Longitudinal wave angle beam 3. Longitudinal wave straight beam OmniScan SX \ MX2 Training – Phased Array Wedges Overview cont. Wedges can be optimized for manual hand inspection, automated scanner inspection, or special applications. Wedge features available include: – – – – – – – – Carbide feet for protection from wear. Built-in irrigation ports and channels. Scanner and encoder attachments points. Inner and outer component radius curvature. Water channels on base of wedge. Stainless steel scanner guides. Multiple positions for the probe. And more…. Rexolite has an outstanding dielectric constant of 2. sonic medical systems. For these reasons Rexolite is an ideal material for phased array wedge manufacturing. sonar lenses. missile guidance systems. . (Does not filter the bandwidth) Rexolite exhibits no permanent deformation under loads up to 2000 psi and at temperatures between 20-125 degrees Celsius. microwave circuitry and many other ultrasonic and optical applications. Rexolite is an isotropic material that has a constant velocity in each axis of 2330 meters/sec and impedance similar to water.5MHz to up to 500 GHz with an extremely low dissipation factor making it well suited for advanced NDT.Rexolite Rexolite is a rigid and transparent plastic produced by cross linking polystyrene with divinylbenzene. (257 degrees Fahrenheit) Rexolite can be machined with tolerances much tighter than Lucite or low grade plastics.OmniScan SX \ MX2 Training – Phased Array Wedges . .OmniScan SX \ MX2 Training – Olympus Wedge Definition The complete definition for wedges is available in the current Olympus probe catalog and below. The part number is divided into 4 sections and may or may not contain the last two. and longitudinal straight beam. Typical housing numbers are A2. In the SA12 example below there are wedge options for shear wave angle beam. longitudinal wave angle beam. Any probe and wedge of the same housing family are compatible. and are printed on the probe and wedge and referenced in the catalog. A12. etc. A10. .OmniScan SX \ MX2 Training – Olympus Wedge Housing Olympus wedges are manufactured to be compatible with the same family of housing. wedge. Wedges compatible with these types of probes contain separate probe position options with separate attachment points including reversing the probe.OmniScan SX \ MX2 Training – Olympus Wedge Housing cont. Care should be taken to ensure the correct probe. Some housing types can accommodate probe models of different pitch size and frequency. position are selected from the wedge database. 2L64 Position 5L64 Position A2 7probe and wedge . and may not be symmetrical in the housing. Failure to complete the calibration process with the same couplant technique and pin position as the inspection will result in a reduction of precision measurement and repeatability. UT couplant gel is not recommended. Wear pins should be secured in place with “Lock-tight” and require a constant water supply through the water ports. The wear pins provide both protection from wear on the wedge.OmniScan SX \ MX2 Training – Wedge Carbide Wear Pins Use of carbide wear pins on the wedges is common for auto and semi-auto inspections where high production or repetitive scanning is required. . Use of carbide wear pins directly affects wedge delay and sensitivity calibration. and stability for improved performance and repeatability. OmniScan SX \ MX2 Training – Wedge Refracted Angle Included in the wedge label after the housing family (SA10. 39 degrees in Rexolite 60 degrees in carbon steel . To achieve a shear wave refracted angle of 60 degrees (N60S) in steel the wedge is cut with an incident angle of 39 degrees in Rexolite. etc) is the nominal refracted angle (N60S) in steel with no beam steering. (Snell’s law) N55 and N60 are common wedge designs because this angle allows good beam steering from approximately 30-70 degrees for most probes\wedge combinations. SA12. OmniScan SX \ MX2 Training – 0L Straight Beam Wedge A zero degree wedge is designed for both straight beam and angle beam longitudinal wave inspection as is typically used in corrosion mapping or composite lamination type inspections. The 0L wedge also protects the probe as scanning with no wedge exposes the probe membrane to wear and damage. . This type of wedge acts as a stand off delay and provides improved near surface resolution compared to using a probe with no wedge. Flat 2.OmniScan SX \ MX2 Training – Wedge Curvature Definition Overview Wedge coupling is essential for a good inspection and where the wedge is too large to properly mate against the material. pipe or vessel inspection are: 1. AOD## (Axial Outside Diameter Curvature + Diameter) 3. COD## (Circumferential Outside Curvature + Diameter) . sound is impeded and the wedge must be contoured. The 3 most common types of wedge curvature for optimization of a particular component. .OmniScan SX \ MX2 Training – Wedge Curvature Definition Overview Other custom wedge configurations are available on request as well as wedges machined to a particular component like a dove tail joint. The phased array calculator need not differentiate between flat and AOD wedges because the probe element position (Height from bottom) is the same for both. Depending on the footprint of the wedge and pipe diameter. In the Olympus probe catalog you will find a reference for the curvature limits for common wedges based on housing type and nominal pipe diameter. separate entries for AOD wedges do not appear in the OmniScan SX\MX2 database. . For this reason. a flat probe may be sufficient for the inspection eliminating the need for an AOD contour.OmniScan SX \ MX2 Training – AOD Wedges AOD wedges are contoured for the pipe diameter for typical girth weld inspections in the axial axis. The COD inspection for the OmniScan MX2 requires that the focal laws be built externally with a computer based calculator like Tomoview and imported into the OmniScan MX2 for use.OmniScan SX \ MX2 Training – COD Wedges Inspection in the circumferential axis or “Long seam” type inspection requires a COD wedge and special hardware and software considerations. COD wedges are calibrated at the factory for precise incident angle to be used in the focal law calculator. Each wedge is treated independently for precision. . The phased array calculator requires the same independent information for the wedge parameters in relationship to the probe. .OmniScan SX \ MX2 Training – Integrated Wedges Wedges can be integrated directly into the probe or custom built for specialized scanners and mechanics. Integrated wedges are used for angle beam and straight beam inspection. OmniScan SX \ MX2 Training – Special Application Wedges . . The Rexoform wedge has an integrated mechanical support that is designed to adapt to different pipe diameters eliminating the rocking effect and minimize the need for a contoured wedge.Rexoform The Olympus Rexoform system uses a specialized 0 degree longitudinal wedge for corrosion mapping applications. The benefits of using water as the wedge include improved component coupling and improved near surface defect resolution. .OmniScan SX \ MX2 Training – Special Application Wedges . It uses a stable water column with an adjustable probe height to transmit sound into the component for corrosion inspection and C-scan generation. The Hydroform wedge parameters for the phased array calculator are selected directly from the database in the SX\MX2 software and use the velocity of water.Hydroform The Hydroform corrosion mapper is a form of a specialized phased array probe and wedge using water as the coupling medium. OmniScan SX \ MX2 Training – Composite Radii Wedge Solution The Olympus Radii solution is a immersion corner wedge for curved linear array probes. Wedge parameters are entered into the calculator for correct beam formation. Allows for internal and external radius inspection and adjustment of different wedge height and radius size. . OmniScan SX \ MX2 Training – Custom Contours In this example the phased array wedge was manufactured to the same taper as the component for a perfect fit. The ability to calibrate wedge delay and sensitivity requires a custom calibration block and precision beam steering and focusing is reduced. Position C-scan Amplitude C-scan . The inspection below is for cracks using an amplitude C-scan and metal loss using a position or “Time of flight” C-scan. Custom wedges than cannot easily be defined by the phased array calculator have inherent limitations. – Low velocity delay lines. – Water box coupling system membranes. Aqualene couplant reduces the drawbacks of wet coupling when used on porous refractory surfaces and acts as a thermal insulator. Aqualene couplant products are available in many sizes and thicknesses including custom design specifications.OmniScan SX \ MX2 Training – Special Application Wedges . Acoustic impedance is nearly the same as water and its attenuation coefficient is lower than many documented plastics. Benefit for customer phased array applications include: – Flexible couplant pads and minimal water addition.Aqualene Aqualene is an elastomer designed specifically for ultrasonic inspection applications. . 2. and improper beam formation. etc. (SA1. and different probe model within the same type of housing. .OmniScan SX \ MX2 Training – Wedge Selection in the OmniScan SX\MX2 In the OmniScan SX\MX2 software the wedge selection and management can be accessed from two locations: 1. Wedges are selected from the database. It is a common source of problems including angle error. wedge delay error. SA2. orientation. Setup wizard. Probe and wedge sub menu. New or custom wedges can be created and stored. One wedge may have many entries based on probe position.) Care should be taken when selecting the wedge model in the software. OmniScan SX \ MX2 Training – Wedge Specification Data Sheet Every wedge from Olympus is delivered with a wedge specification data sheet that contains all of the parameter values to populate the OmniScan MX2 database or external focal law calculator. . For that reason one wedge may be listed many times in the database. These values are relative to the probe and its orientation on the wedge. At any time the current wedge database can be directly updated on the OmniScan MX2 memory card by downloading a utility from the software support section of the Olympus web page at www.OmniScan SX \ MX2 Training – Wedge Database Update on the Web New wedges are added to the database periodically at different intervals than the software updates.com .olympus-ims. (Normal or reverse) Height of element #1 of the probe (h1).y).OmniScan SX \ MX2 Training – Phased Array Wedge Parameters Overview The following parameters are required for the OmniScan MX2 wedge database and phased array calculator: – – – – – Wedge model. Wedge material velocity. Wedge orientation. (2330m/s Rexolite) – Primary and secondary offsets (x. Wedge angle. . and delay errors that cannot be overcome in the calibration process.Angle Question: What is the affect on the UT data if the wedge angle is different than the calculator (Wizard) input? Answer: The beam formation is incorrect resulting in angle. Minor angle errors due to machining tolerances are the same as conventional UT wedges and typically need not be corrected with precision measurement on specific wedge serial number.OmniScan SX \ MX2 Training – Phased Array Wedge Parameters . . focusing. It can be measured mechanically and ultrasonically.OmniScan SX \ MX2 Training – Phased Array Wedge Parameters . If it is different than the database or more precision is required it can be entered as a new or custom wedge. .Angle Question: Can the angle of the wedge be measured if it is unknown? Answer: Yes. The procedure for measuring the wedge angle ultrasonically is covered in the acoustic validation section. OmniScan SX \ MX2 Training – Phased Array Wedge Parameters .Orientation Due to the scanner limitation or inspection access it is sometimes necessary to reverse the orientation of the probe elements to accommodate the probe cable. This is a function of the wedge orientation and it is defined as either normal or reverse. (1-64 changes to 64-1) . Selecting reverse will have the affect of reversing the probe element wiring. The selected focus distance in the material is short or long based on the error. . Angle is not affected.OmniScan SX \ MX2 Training – Wedge Parameters – Height of Element 1 Question: What is the affect on the UT data if the height of the first element is different than the calculator (Wizard) input? Answer: The wedge delay of the beam is not calculated correctly resulting in depth reading errors. Wedge delay can be corrected in the calibration wizard. OmniScan SX \ MX2 Training – Wedge Parameters – Height of Element 1 Question: Does normal usage result in wedge wear that will change the height of the first element? Answer: Yes. This can be corrected in the wedge delay calibration wizard or created in the wedge database as specific serial numbered wedge. This is normal and can be minimized with use of carbide wear pins on the wedge. wedges in some environments are consumables. Unlike probes. . OmniScan SX \ MX2 Training – Phased Array Wedge Parameters .Height Question: Can the height of the first element on the wedge be measured if it is unknown? Answer: Only ultrasonically. not mechanically. (Inspecting the wedge) This process is covered in a later section. It cannot be measured mechanically because element #1 is hidden behind the membrane in the probe housing and it is impossible to know the exact position to measure. . This is done by using the fixed velocity of the wedge as the component. Rexolite is an isotropic material that has a constant velocity in each axis of 2330 +\.Velocity The velocity of the wedge must be known prior to formation of the focal laws. Temperature affects velocity and similarly to conventional UT the calibration must be performed near the same wedge and component temperature as the inspection.20 meters\sec Wedge velocity like component velocity is directly related to the incident and refracted angles and is an essential variable in the calculator.OmniScan SX \ MX2 Training – Phased Array Wedge Parameters . (Snell’s Law). It cannot be measured or corrected during the calibration process. . Most wedges from Olympus that are designed to be used with the OmniScan MX2 are made of Rexolite. OmniScan SX \ MX2 Training – Wedge Parameters . X is the primary offset and Y is the secondary offset and is normally 0mm. (-69mm below) . The element #1 position is normally referenced from the front of the wedge face and for that reason the number is negative.Offsets Offsets are the relationship of probe element #1 to the side and front of the wedge. As pictured right. and only the rulers.Offsets Question: What is the affect on the UT data if the primary offset is wrong? Answer: The beam exit point is miscalculated by the software and the surface distance to the indication is incorrect. The offsets are only for determining position and do not affect beam formation. weld overlay. . and skip lines are wrong. trigonometry and depth readings are normal. The A-scan appears normal.OmniScan SX \ MX2 Training – Wedge Parameters . Offsets Question: Is it possible to know the primary offset of element #1 by measuring it on the probe and wedge? Answer: No. . The probe elements are not visible through the protective membrane and the position of element #1 cannot be measured with precision. The offset position must come from the drawing of the probe married to the wedge. Close approximations are unacceptable and result in reduced precision.OmniScan SX \ MX2 Training – Phased Array Wedge Parameters . OmniScan SX \ MX2 Training – Phased Array Wedge Review What are the essential parameters of 1D linear array wedge that are required by the OmniScan SX\MX2 software? 1. Wedge orientation. 4. . Wedge velocity. 3. Height of element #1 on probe. 5. Wedge offsets. Wedge model number. 2. Probe parameters. 2. Beam Formation.OmniScan SX \ MX2 Training – Phased Array Focal Law Calculator Review What are the essential parameters for the phased array calculator? 1. 3. Wedge parameters. . Material Velocity 4. 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