SCOPE This section is intended for the guidance of NDE personnel qualified in accordance with the requirements of M&NP Training and Qualification of Personnel. The inspection processes and procedures described in this document may be used for line pipe, piping components and pressure vessel plates. Ultrasonic Thickness testing may also be used to evaluate the thickness of the parent material after grinding etc. This procedure is not intended to be exhaustive in the treatment of ultrasonic technique as it is provided for general guidance only. SAFETY Prior to excavation for inspection, verification shall be made that the pipeline has been established at a safe working pressure in accordance with the requirements of O&MSM Section 12, Reference 17 - Safe Working Pressure. Defect excavation shall then be completed in accordance with the requirements of O&MSM Section 11, Reference 13 - Defect Excavation and Assessment. EQUIPMENT A. INITIAL SETUP 1. Introduction Figure 1 T-MIKE E For those settings which are seldom changed during operation of the T-Mike E the INITIAL SET UP procedure is designed to allow the operator access to those settings without unnecessary complication of the units normal operation. These settings include: Backlight on/off Selection of Metric or English units of measure Calibration Lock Page 1 of 10
The INITIAL SET UP procedure is accessed by holding the CAL key down and pressing the ON/OFF key. When this is done the T-Mike E will display the version code of the operating software contained in the unit until the CAL key is released. This information will be useful should the unit require service or updated software is desired. Upon release of the CAL key the SETUP procedure continues as follows: 2. Backlight On/Off When the CAL key is first released the T-Mike E will display the words ON or OFF to indicate the status of the backlight. The backlight setting can be selected by pressing the UP or DOWN arrow key. NOTE: It is recommended that the backlight be OFF when measurements are made in well-illuminated areas, as this will greatly increase battery life. 3. Metric/English Units Press the CAL key a second time. The T-Mike E will display the units in which it is set to measure thickness (IN or MM). Press the UP or DOWN arrow keys to select the desired unit of measurement. 4. Calibration Lock Press the CAL key a third time. The T-Mike E will display the status of the calibration lock function (CAL or LOC). When Cal is displayed the velocity calibration function can be performed as described in the 4 th step under section B, OPERATION. When LOC is displayed the calibration function is disabled. The velocity used in measurement cannot be changed without entering this SETUP procedure again to change settings to CAL. It is recommended that the lock feature be used when supervising personnel wish to prevent unauthorized change of the calibrated velocity. Pressing the Cal key a final time completes the SETUP procedure and returns the T-Mike E to the measurement mode. B. OPERATION Page 2 of 10
1. Lemo quick-disconnect transducer connectors. 2. Battery charger connector / data port. 3. Built-in calibration block. 4. Coupling indicator. 5. Backlit amber LCD indicates modes, measurements and icons. 6. Durable, lightweight, extruded aluminum case. 7. Environmentally sealed keypad. 8. Power key. 9. One-step material calibration key. 10. Arrow keys for calibration. 11. Operator selectable metric or English measurement mode. 1. ON/OFF Function (item 8 on Figure 2) Figure 2 T-Mike E - Front Panel Press this key to turn the T-Mike E on. The unit will display a reading of zero. The T-Mike E is now ready for measurement of calibration. In order to compensate for any change in the ultrasonic transducer, a PROBE ZERO function should be performed at this point. 2. Probe Zero Function The PROBE ZERO function compensates the T-Mike E for the fixed delay of the ultrasonic transducer. This function should be performed at the start of each day (to compensate for transducer wear) or whenever the transducer is changed. Apply a drop of couplant to the end of the transducer. Press the ON/OFF button on they keyboard to turn on the T-Mike E. Place the transducer in steady contact with the probe disk located on the top of the T-Mike E. DO NOT use another 0.250 test piece since the velocity of the probe disk is carefully controlled and errors will result. The T-Mike E recognizes that the probe is in contact with the probe disk, and automatically performs the PROBE ZERO function. Upon completion of the function Prb 0 will appear on the display indicating that the appropriate transducer delay factor has been entered into memory. NOTE: During the PROBE function, the T-Mike E velocity is temporarily reset to the velocity of the probe disk (0.2330 in./msec.). Upon completion of the PROBE function the velocity will return to the last calibrated value. This allows the operator to continue measurements on the previously calibrated material. Page 3 of 10
3. Material Calibration to Known Thickness The following procedure is used to calibrate the T-Mike E sound velocity to a known sample of material. Some materials may exhibit sound velocity variations which can cause errors in measurement. Be sure to check a representative group of samples to determine if such variation is present. First follow the above PROBE ZERO procedure (step 2) to calibrate the delay of the ultrasonic transducer being used. Apply a drop of couplant to the representative piece of material of known thickness. This piece is called the sample. Place the probe in steady contact with the surface of the sample. The T-Mike E will display a thickness reading using the last calibrated velocity. Press the CAL key (item 9 in Figure 2) to lock in the reading. The transducer may now be removed from the sample. The display on the T-Mike E will momentarily display CAL. Small arrows will appear in the upper left portion of the display above the thickness readings. This indicates that the T-Mike E is in the calibration mode and enables the UP/DOWN arrow keys. U P Adjust the thickness shown on the T-Mike E display by using the UP and DOWN arrows (item 10 in Figure 2). Note that when these keys are held continuously, the speed at which the thickness changes will increase, making it easy to make the large adjustments for materials such as plastic and aluminum. When the correct thickness appears on the display, press the CAL key again to display the sound velocity of the calibrated material as calculated by the T-Mike E. The display of sound velocity will be indicated by the appearance of appropriate velocity units (IN/ms or M/S) above the displayed velocity value. Press CAL key one final time to accept this sound velocity and return to the measurement mode. Check the calibration by replacing the probe on the sample piece. The T-Mike E is in the CALIBRATION mode the unit will not make further measurement until the calibration procedure is completed. 4. Calibration from Known Velocity The following procedure is used to calibrate the T-Mike E to a given material velocity. Follow the above PROBE procedure to calibrate the delay of the ultrasonic transducer being used. Press the CAL key (item 9 in Figure 2). The arrow symbols will appear in the upper left portion of the display indicating the UP/DOWN arrow keys are active. Press the CAL key a second time. The display on the T-Mike E will display the current velocity and the appropriate units of measure. Page 4 of 10
IN /µ s. 2 3 3 0 Or if metric units are selected: m / s 5 9 1 8 UP Use the UP and Down arrow keys to scroll to velocity to the known velocity of the material. Note that when these keys are held continuously, the speed that the velocity changes will increase, making it easy to make the large adjustments for materials such as plastic and aluminum. DOWN When the desired velocity appears on the display, press the CAL key again to enter the velocity for use in thickness measurements and to return to the measurement mode.. 5. Thickness Measurement Remove dirt, loose material, and couplant residue from the surface of material at points where measurements are desired. Verify that the PROBE and CAL functions have been performed. Place a drop of couplant on the material surface at the measurement point. Place the transducer in steady contact with the surface of the material at the measurement point. When a detectable echo is received from the back surface of the material, the echo indicator in the upper right of the display will indicate the detection of an echo by changing in appearance to represent contact between the pictured transducer and the same surface. NO ECHO ECHO DETECTED Page 5 of 10
The T-Mike E will display the thickness of the material and the appropriate units of measure (inches or millimeters). NOTE: If the detected echo is of marginal magnitude a question mark? Will appear to the left of the echo indicator. This will alert the operator that the measurement may be subject to error, and steps should be taken to improve the transducer coupling or position. ON OFF If no echo is detected for a period of 4 ½ minutes, the T-Mike E will automatically switch to its low power or dormant state as indicated by the display becoming blank. In this state probe and velocity calibration factors are retained in memory. Operations may be resumed immediately by pressing the power key. 6. Measurement Units The T-Mike E can display thickness in either English or Metric units. The unit system may be selected during the INITIAL SETUP of the T-Mike E as described previously. 7. Low Battery The T-Mike E automatically monitors the charge state of the battery to insure that sufficient charge is available to operate the unit properly. When the T-Mike E detects minimum allowable battery level the numbers on the display will blink on and off. This alerts the operator that the batteries should be replaced or recharged before further operation. When the battery level fails below the minimum allowable level the T-Mike E will turn off and not allow further operations until batteries are replaced or recharged. 8. Replacing or Recharging Batteries The T-Mike E comes standard with 4 AA alkaline batteries. The user may elect to use rechargeable NiCad AA batteries that can be inserted as a direct replacement of the alkaline cells. The NiCad batteries may be charged externally or in the T-Mike E as described below. To change the batteries, loosen the screw on the bottom end cap and remove the spent batteries. Replace batteries with fresh Alkaline AA cells or recharged NiCad AA cells. Care must be used to replace the batteries in the correct polarity as indicated on the battery holder. To recharge the NiCad batteries in the T-Mike E connect the optional battery charger to the combination DATA/CHARGER jack on the top end cap (item 2 of Figure 2) of the T-Mike E. The NiCad batteries will be fully charged in approximately 14 hours. NOTE: After changing batteries be sure to perform the probe zero procedure and recalibrate the T-Mike E for the material to be measured. Page 6 of 10
C. T-MIKE PROGRAMMABLE 1. Configuration and Calibration The T-Mike Programmable is preset to display in inches or millimeters; the back light enabled or disabled; and the sound velocity fixed. This can be done at the factory prior to shipping or this may be done by connecting the T-Mike programmable to an IBM compatible computer running special software, or from a T-Mike E. When using a T-Mike E, a special cable is required. 2. To Program From a T-Mike E Set the T-Mike E in the desired mode by holding down the CAL key while turning on the power. Now calibrate the sound velocity of the T-Mike E to the desired sound velocity. Turn off both gauges. Connect the special cable between the two data/charger ports. Turn on the T-Mike E; press the Cal key twice and the LCD will indicate the velocity. Now turn on the T-Mike Programmable. The T-Mike Programmable should display CAL, followed by the new velocity and then will go into the measurement mode. Be sure this new velocity matches with the sound velocity in the T-Mike E. 3. To Program from an IBM Compatible PC Remove rubber plug from the serial port of the T-Mike and insert the LEMO connector of the T-Mike serial cable (Part Number 022-506-783). Connect the serial cable to COM1 or COM2 of the PC. Run SETMIKE from Start/Programs/Stresstel or from the appropriate installation directory. Select Measurement Unit: Inches or Millimeters. Enter sound velocity in inches/us or M/S. Press Enter to accept the new velocity. Check Backlight to illuminate T-Mike reading. Select Serial Port: COM1 or COM2. \\Stresstel SetMike T-Mike Settings Measurement Units Inches Millimeters Transmit Settings Serial Port COM1 COM2 X Velocity (M/S) Language 5918.2 English Use the Tab key to cycle through the SETMIKE Windows application controls. Backlight SEND CLOSE Press SEND to initiate update of the T-Mike. Turn on the T-Mike. If the T-Mike was already on, turn it off and turn on gain. \\Stresstel T-Mike Update X The T-Mike P/B may require several attempts to synchronize with SETMIKE. Repeat Off/ON cycles until the correct velocity appears in the display. Turn on instrument Now CLOSE Page 7 of 10
When you turn off the T-Mike Programmable, it will display the EPROM software version. When you turn on the T-Mike Programmable, it will momentarily display the calibrated sound velocity. Test the T- Mike Programmable on a material sample to verify that it reads the correct thickness. 4. Special Cables From a T-Mike E to T-Mike Programmable Part # 062-500-055 From IBM Compatible Computer to T-Mike Programmable adaptor 9 pin to 25 pin Part # 021-031-995; 9 pin Part # 022-506-783 D. T-MIKE BASIC 1. Configuration and Calibration The T-Mike Basic has five operator selectable materials (steel, aluminum, stainless steel, cast iron, and plexiglass) with is preset sound velocities. One custom material ca be programmed by connecting the T- Mike B to an IBM compatible computer running special software, or from a T-Mike E. In either case, a special cable is required. 2. Material Selection First follow the above PROBE ZERO procedure to calibrate the delay of the ultrasonic transducer being used. MAT Press the MAT key to select the material being tested. Select the material by using the UP and DOWN arrows. Press the MAT key a second time to store the velocity for the selected material. Some materials may exhibit sound velocity variations which can cause errors in measurement. Be sure to check a representative group of samples to determine if such variation is present. 3. Initial Setup In order to change the settings of the T-Mike B, the instrument must be powered on in the Initial Setup mode. The settings, which may be changed, are the units of measure and the backlight. This procedure is defined in the INITIAL SETUP ( A page 1). Use the MAT key on the T-Mike B as CAL key referenced in the procedure. 4. To Program from a T-Mike E Set the T-Mike E in the desired mode by holding down the CAL key while turning on the power. Now calibrate the sound velocity of the T-Mike E to the desired sound velocity. Turn off both gauges. Connect the special cable between the two data/charger ports. Turn on the T-Mike E; press the CAL key twice and Page 8 of 10
the LCD will indicate the velocity. Now turn on the T-Mike B. The T-Mike B should display CAL, followed by the new velocity and then will go into the measurement mode. Be sure this new velocity matches with the sound velocity in the T-Mike E. 5. To Program from an IBM Compatible PC Remove rubber plug from the serial port of the T-Mike and insert the LEMO connector of the T-Mike serial cable (Part Number 022-506-783). Connect the serial cable to COM1 or COM2 of the PC. Run SETMIKE from Start/Programs/Stresstel or from the appropriate installation directory. Select Measurement Unit: Inches or Millimeters. Enter sound velocity in inches/us or M/S. Press Enter to accept the new velocity. Check Backlight to illuminate T-Mike reading. Select Serial Port: COM1 or COM2. \\Stresstel SetMike T-Mike Settings Measurement Units Inches Millimeters Transmit Settings Serial Port COM1 COM2 X Velocity (M/S) Language 5918.2 English Use the Tab key to cycle through the SETMIKE Windows application controls. Backlight SEND CLOSE Press SEND to initiate update of the T-Mike. Turn on the T-Mike. If the T-Mike was already on, turn it off and turn on gain. \\Stresstel T-Mike Update X The T-Mike P/B may require several attempts to synchronize with SETMIKE. Repeat Off/ON cycles until the correct velocity appears in the display. Turn on instrument Now CLOSE When you turn off the T-Mike B, it will display the EPROM software version. When you turn on the T- Mike B, it will display the active material. Press MAT again to display the sound velocity. Test the T- Mike B on a material sample to verify that it reads the correct thickness. E. HELPFUL HINTS on OPERATION 1. Backlight The T-Mike E features a backlight LCD display. The display illuminates when tan echo is detected. Using the backlight will significantly reduce battery life. Therefore, you may wish to deactivate the backlight when using the T-Mike E in a well-lit environment. 2. Clean the Surface Clean the probe and the material to be material to be measured and apply only enough couplant to obtain a steady, valid reading. Usually one drop is enough. Page 9 of 10
3. Material Consistency Maximum measurement accuracy will be contained if the work piece and the calibration piece are the same temperature, shape, material, and size. NOTICE Since velocity of sound varies from test piece to work piece, accuracy of measurement depends on consistency of ultrasonic velocity. Ultrasonic velocity also varies with internal stress, so that heat treatment of the material will also affect accuracy. The following table expresses accuracy variations for some common materials. NOTE: These specifications are intended only as a general guide. Actual accuracy may be different. Aluminum +/- 2% Cast iron +/- 8% Steel +/- 0.5% Nylon +/- 10% Page 10 of 10