phase II+ UTG-4000 User manual

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ModelNo.UTG‐4000
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www.phase2plus.com
283 Veterans Blvd
Carlstadt, NJ. 07072
[phone]
www.phase2plus.com
21IndustrialAveUpperSaddleRiver,NJ.07458
P(201)962‐7373 F(201)962‐8353
E‐mail:[e-mail]

CONTENT
1. GENERAL INTRODUCTION3
1.1 CONSTRUCTION OF THE GAGE........3
1.2 STANDARD CONFIGURATIONS.........3
1.3 OPTIONAL CONFIGURATIONS..........3
1.4 SPECIFICATIONS.............................4
1.5 MAIN FUCTIONS..............................5
2. KEYBOARD FUCTIONS5
3. MEASURING THE THICKNESS6
3.1 PRESET THE MATERIAL’S VELOCITY6
3.2 PRESET OTHER SPECIFICATIONS....7
3.3 CALIBRATION.................................8
3.4 DISPLAY MODES.............................9
3.5 ADJUSTING THE SPECIFICATIONS IN A-SCAN MODE
........................................................11
3.6 REAL CASES ANALYSIS................12
4.CARE AND MAINTENANCES16
4.1 POWER SOURCE INSPECTION......17
4.2.......................................Maintenance
4.3 Service / Support..........................17
APPENDIX: SOUND VELOCITIES OF COMMON MATERIALS17

1. GENERAL INTRODUCTION
UtilizingliveA‐scanandtimebasedB‐scanforabsolutecorrectness,thisnewstateoftheart
thicknessgaugeispackedwithusefulfeaturesallowinguserstobeconfidentofthedisplayedvalueson
themostcriticalofapplications.Thismulti‐functionalunitofferseverythingfrombasicmeasurement,
ScanwithMin/Maxviewing,GO/NOGOdisplayandAdjustableSoundVelocity.Thisdynamicsonicgauge
isde s i g n e d tomeasurethethicknessofmetallicandnon‐metallicmaterialsincriticalsituationsthat
ordinarythicknessgaugescouldn’tdo. 
TheUTG‐4000willaccuratelydisplayreadingsineitherinchormillimeterafterasimplecalibrationto
aknownthicknessorsoundvelocity.
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1.1CONSTRUCTIONOFTHEGAGE
1.2STANDARDCONFIGURATION
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Qty
ThicknessGauge 1
5MHzPROBE 1 
AABatteries 2
2ozCouplantGel 1
RuggedCarrycase 1
OperationManual 1
1.3OPTIONALACCESSORIES
High‐temperatureprobe Castironprobe
SmallProbe(6mm) MiniProbe(4mm)
Probecable 5‐Stepblock
DISCLAIMER:
TheUTG‐4000isamulit‐functionalthicknessgaugethatallowstheusertremendouscontroloverthefunctionalityandperformance
ofthisinstrument.Althoughthis providestheuser withcontrolandversatilityfornumerousapplications,italsorequiresthatthe
userbefamiliarwiththefunction,operationandwaveforminterpretationoftheinstrumentaswell.
Itisrecommendedthattheuserspendasufficientamountoftimeworkingwiththisinstrumentpriortofielduse.
Responsibilityforproperuserestssolelywiththeuseofthisinstrument.

1.4SPECIFICATIONS
OperatingPrincipleUltrasonic pulse/echo method with dual
elementprobe
Displaytype2.4”ColorScreen
Resolution0.001”,.01”/0.01mm(Inch/Metricselectable)
MeasuringRange0.02‐20.0”   Dependantuponprobe&material
Repeatability+/‐.001”    (+/‐0.05mm)
Soundvelocityrange0.0197‐0.3937in/us   (500‐9999m/s)
MeasuringError:0.001”(upto0.984”)
0.007”(upto3.03”
0.019”(4”andabove)
DisplayModes:DigitalThicknessReadout
A‐scanorB‐scan
Min/MaxCapture
Diff‐Value/Reduction
V‐PathCorrectionAutomatic
UpdateRateSelectable:4Hz,8Hz,16Hz
Refreshrate4/second
AlarmSettingsMin/MaxAlarm
Dynamicwaveformcolorchangeonalarm
Operatingtemperature14‐122ºF    (‐10ºC‐+50ºC)
AutoShut‐OffAfter5minutes
Powersupply3vAAalkalinebatteries(2pc)
OperatingTimeApprox.36hours 
Dimensions6.02”x2.99”x1.45”   (153x76x37mm)
Weight9.9oz    (280g)

1.5MAINFUCTIONS
1.User‐friendlyinterface
2.OptionalA‐scanwaveformdisplay
3.TimebasedB‐scanfunctiondisplayscrosssectionoftestpiece
4.Differentcouplingstatusshowingindifferentcolors 
5.Thicknessalarm:automaticalarmwhentheresultexceedsthepresetthicknessrange 
6.Limitsvaluemode:Displaystheminimumandmaximumvalueswhenmeasuring
7.Differencemode:gettingthedifferencebetweentheactualvalueandthenormalvalueaswellasthe
percentage
8.Inch/MetricConversion
9.Extralargememory:upto100,000values&1000waveforms
10.SelectableResolution:0.001”,0.01”or.01mm
11.Optionalrectificationmode:RF,fullwave,half+,half‐
12.Optionalwaveform:outlinemodeorfilledmode
13.Approx.batteryLife:35hours
2.KEYBOARDFUCTIONS
Totally,thereare9keysonthekeyboard,including3virtualfunctionkeys(),fourdirection
keys(),twospecializedfunctionkeys().Seethefollowing
illustration(2.1) 
2.1KEYBOARDFUCTIONILLUSTRATION

3.MEASURINGTHICKNESS
3.1SoundVelocityCalibration
In order for the gauge to make accurate measurements, it must besettothecorrectsoundvelocityforthe
materialbeingmeasured.Differenttypesofmaterialhavedifferentinherentsoundvelocities.Ifthegaugeisnotsetto
thecorrectsoundvelocity,allofthemeasurementsthegaugemakeswillbeerroneousbysomefixedpercentage.The
One‐Pointcalibrationisthesimplestandmostcommonlyusedcalibrationprocedureoptimizinglinearityoverlarge
ranges. The Two‐pointcalibration allows for greater accuracy over small ranges by calculating the probe zero and
velocity. 
Note:OneandTwopointcalibrationsmustbeperformedonmaterialwiththepaintorcoatingremoved.Failureto
removethepaintorcoatingpriortocalibrationwillresultinamultimaterialvelocitycalculationthatmaybedifferent
fromtheactualmaterialvelocityintendedtobemeasured.
Calibrationtoaknownthickness
Note:Thisprocedurerequiresasamplepieceofthespecificmaterialtobemeasured,theexactthicknessof
whichisknown,e.g.fromhavingbeenmeasuredbysomeothermeanssuchasacaliperormicrometer.
1) Performatestonthebuilt‐intestblocktoverifyunitisfunctioningproperly 
2) Applycouplanttothesamplepiece.
3) Pressthetransduceragainstthesamplepiece,makingsurethatthetransducersitsflatagainstthesurfaceof
thesample.Thedisplayshouldshowsomethicknessvalue,andthecouplingstatusindicatorshouldappear
steadily.
4) Havingachievedastablereading,removethetransducer.Ifthedisplayedthicknesschangesfromthevalue
shownwhilethetransducerwascoupled,repeatstep3.
（5） Pressthedirectionkeystoadjustthevelocitytomaketheactualthicknessvaluebesamewiththeknown
value. 
2.Adjustthevelocitydirectlyifthematerialvelocityisknown.Seeillustration3.1:
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3.1VELOCITYADJUSTINGSTEPS
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3.2PRESETOTHERSPECIFICATIONS
Press “M”toentertheuserinterface,whichallowsyoutoselectandadjust options like VIEW
MODE, PROBE SETUP, MINIMUM ALARM, MAXIMUM ALARM, NORMAL THICKNESS, MINIMUM of
B‐SCAN, MAXIMUM of B‐SCAN, RECTIFICATION, RECTIFICATION WAVEFORM, RESOLUTION,
LANGUAGE,UPDATERATES,UNITS,ANDDEFAULTSETUP.Seethefollowingfigure:  
3.2MenuSelections
VIEWMODE:normalmode,differencemodeandlimitscanningmode. 
PROBESETUP:PT‐10/PT‐08(normalprobe),PT‐06(smallprobe),PT‐04(miniprobe),GT‐12(high‐temperature
probe),andZT‐12(castironprobe).
MINIMUMALARM: set the minimum thickness alarm value. The result will be displayedinrediftheactual
thicknessislessthantheminimumvaluepreset.
MAXIMUMALARM: set the maximum thickness alarm value. The result will be displayedinrediftheactual
thicknessismorethanthemaximumvaluepreset.
NORMALTHICKNESS:setthenormalthickness.Therealconcreteapplicationwillbe introduced in the
DIFFERENCEMODE.
MINIMUMofB‐SCAN:setminimumthicknessforB‐scan
MAXIMUMofB‐SCAN:setmaximumthicknessforB‐scan
RECTIFICATIONMODE: RF, full wave, half ‐, half +. RF describes the complete echo waveform; full wave
indicatesthehalf+echoandtheoverturnedhalf‐echo;half–meansputtingoffthehalf+echoandturnthehalf
–overto+;half+meansputtingoffthehalf–echoandonlyleftthehalf+echo. 
RECTIFICATIONWAVEFORM:outlinemodeandfillmode.
RESOLUTION:SelectableResolution:0.001”,0.01”or.01mm
LANGUAGE:theinterfacelanguage:ChineseorEnglish.

UNITS:Selectable:mmorinch.
UPDATERATE:Updatetherateofmeasurementresult.Optional4,8or16Hz.
AUTOPOWERDOWN:Thedevicecanbesettoshutoffafter5,10,20minutesofinactivity.IfsettoOFFthenthe
Cal/ONbuttonwillpowertheunitonoroffwhenpressed.
DELETEALLFILES:Emptyallmemoryofvaluesandwaveforms.
DEFAULTSETUP:Bringsunitbacktooriginalfactorysettings
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3.3CALIBRATION
Before using the UTG‐4000, calibrating the gage as well as the probe is necessary. See the following
steps:

  
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3.3CALIBRATIONSTEPILLUSTRATION
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1.Adjustthesoundvelocityto5900m/saccordingtothemethodinchapter3.1.
2.Afterturningonthegage,presstoenterthecalibration interface. The screen shows PUT
PROBEONZEROBLOCKUSECOUPLANT.
3.Spreadthecouplantaccordingtothepresentation,thenputtheprobeonthezeroblockandmakeit
coupledcompletelyuntilthescreenshowsACQUIRINGPLEASESTAYCOUPLED.
4.Holdafewseconds,andthescreenwilldisplayPROBEZEROCOMPLETEREMOVEPROBEFROMZERO
BLOCK. Remove the probe from the zero block and it goes back to the measuring interface
automatically. 
5.Duringthecalibration,presstheABORTatanytimetostopcalibrating andtheunitwillgo
backtothemeasuringinterface. 
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3.4DISPLAYMODES
Therearethreemeasuringinterfacedisplaymodes:normalmode,A‐scanmodeandB‐scanmode.
AndtherearethreedisplaymodesofNormalinterface:Thethicknessvaluemode,Difference/rateof
reduction measurement mode, MAX/MIN measurement mode. Select this in “VIEW MODE” of
configuration.
ATTENTION:Whentheprobeisproperly“coupled”tothesurfaceoftheobjectbeingtested,the
displaywillbeshowninWHITE.IfnotcoupledproperlythenthevalueswillbeshowninGREEN.When
thevaluesexceedtheupperorlowerlimitsettingthenthevalueswillbeshowninRED.
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THICKNESSVALUEMODE:Thisinterfacemainlyshowsthevelocityofmaterial,thepresentthickness
valueandunit.  
3.4NORMALMODEINTERFACE
1—thepresentthicknessvalue2—unit3—materialvelocity4—batterypower5—A—scaninterface
DIFFERENCE/RATE‐OF‐REDUCTIONMODE: This interface shows the measured value, the preset
nominalthicknessvalue,thedifferencebetweenthemeasuredvalueandthepresetvalueandtheratio
betweenthedifferenceandthenormalvalue.Beforeusingthismode,presettingthenominalthickness
isneeded.Themethodcanbetakenaccordingtochapter3.6.
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3.5DIFFERENCEMODEINTERFACE
1—the difference between the normal value and the preset value 2—theratiobetweenthe
differenceandthenominalvalue3—thepresentthicknessvalue   4—thenormalvalue
5—differencesignal6—materialvelocity7—batterypower8—A—scaninterface
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LIMITSVALUESCANNINGMODE:thismodeallowsthecustomertotest the thickness of material
continuouslyandtoshowtheupper/lowerlimitsafterthetests.Itshowstheminimumandmaximum
valuesduringthetestsaswellasthepresentthickness.PresstheRESETtogetthelimitswhen
measuringthethickness. 
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3.6LIMITSVALUEMODEINTERFACE
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1—thepresentthicknessvalue2—themaximumvalue3—theminimumvalue4—unit
5—materialvelocity6—batterypower7—A—scaninterface8—reset

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A‐scanmode:ThisinterfaceallowsyoutoseethepresentthicknessvalueandtheA‐scanwaveformat
thesametime.Therightsideoftheinterfaceisthespecificationadjustingarea,whichcanbeadjusted
foramorepreciseresult.Thedetailedintroductioncanbeseeninchapter3.5.
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3.7A‐SCANMODEINTERFACE
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1—waveformdisplayarea2—gate3—materialvelocity4—thepresent highlighted
specification5—measuringpoint(thefirstpointofintersectionbetweenthewaveformandthegate)  
6—thepresentthicknessvalue7—theblankconfines
8—therangeconfines   9—thespecificationadjustingarea   10—highlightedsignal   
11—digitmode12—specificationswitch13—batterypower
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ATTENTION:Whentheprobeandtheobjectarenotcompletelycoupled,theletters in the various
interfacesareshowninGREEN,whenproperlycoupled,theyaredisplayedinWHITEcolorandwhen
theeithertheupperorlowerlimitsareexceeded,thelettersaredisplayedinREDcolor. 
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3.5ADJUSTINGTHESPECIFICATIONSINA‐SCANINTERFACE
IntheA‐scaninterface,pressthebottomrightbuttonNEXTtohighlightthevaluetobeadjusted.
Thenpressthedirectionkeystoadjustthevalues.Upanddownkeysareusedforsmallincrements,
whileleftandrightforlargerincrements. 
GAIN—adjustthesensitivityofthegagewithunitdB.Thelargerthegainis,thehigherthesensitivityis.
Thegainrangesfrom8to55dB.
RANGE—adjustthetestingrangethatthescreendisplays.Therangeis0.393”to5.70”(10~145mm).
DELAY—shown at the beginning point of the screen. The waveform will move horizontally when
adjustingthisvalue. 
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BLANK—hide the unnecessary and useless clutter in front of the main waves. The red line on the
bottomofthescreenshowstheblankconfines.Theadjustingblankconfinesarethepresentrange
confines. Incorrect readings can be caused by material issues such as corrosion, internal material
defectsorevenaspecificmaterialsuchasaluminum.OnlyadjustmentsintheGaincansolvepartofthe
problem.
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GATE—locktheechoandshowthethicknessvalueofthehighestecho.Adjustingtheheightofthegate.
Thegaterangesfrom1to50mm.Onlywhenthewaveformishigherthanthegatewillthisgaugebe
abletotaketheechoandshowthevalue.
Attention:thiswillonlyshowwhentheGATEspecificationishighlighted. 
ThefirstintersectionpointbetweenthewaveformandgateisshownwithaREDarrowwhichwillhelp
youdetermineif this thicknessvalueis correct. If correctlytested, the redarrowshould point tothe
frontofthefirstbottomecho.
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3.6REALCASEANALYSIS
1.Whenmeasuringthethickness,itspossiblethatsmallgainspreventthepreciseresults.Asshownin
thefollowingfigure,thethicknessofthetestingobjectisabout5mm,butasfortheoversmallgain,the
measuringresultis10.77mmasthefirstechohasnotbrokenthegateandthegatelocatesthesecond
echoautomatically.Thisisobviouslyanincorrectresult,andcustomercanpulluptheechoby
enhancing the gain setting to make the first echo break the gate and finally pinpoint the correct
measurement.
3.8 REAL CASE 1

2.Therearesomedefectsinthe testingobject,andthegatelocksthedefectechoes.Asshowninthe
followingfigure,thethicknessofthetestingobjectisabout10mm,butasthereareobviousdefects(the
defectechoesareshownonthedisplay)andthegatelocksthedefectechoeswhichhavebrokenthe
gate,thus,thetestingresultshownisthethicknessofthedefectarea.Therightmeasurementcanbe
realizedbyadjustingthegatesettingabovethedefectechoes.
3.9 REAL CASE 2
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3. If there are some surface faults in the testing object and the gate locks the defect echoes, the
measuringresultwillbethethicknessofthedefectarea.Inthis condition,thecustomercan usethe
BLANK function to get the correct testing result. As shown in the following figure, the line on the
bottomofthescreen,whichweusetoshieldthedefectechoes,indicatestheblankconfinesandmakes
thegatenotcatchtheechoeswithintheblankconfines,thus,therightthicknessvalueisacquired.   
3.10 REAL CASE 3

3.7OPERATIONOFB‐SCANINTERFACE
3.7.1B‐ScanDisplay
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1) B‐scanimagedisplay
2) Whitepointer
3) Redtriangle(displaysminthickness)
4) Thethicknessvalueofthepointerposition
5) TheminimumthicknessrangeinB‐scan
6) ThemaximumthicknessvalueinB‐scan
7) ErasingthecurrentB‐0scanimagesandmeasurements
8) Enterthenumericalmeasurementinterface
9) Soundvelocity
10)TheminimumthicknessvalueontheB‐scanimage
11)Parameterdisplayarea 
12)Gainvalue
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3.72IntroductiontoB‐scan
The UTG‐4000 has a time base B‐scan function. By moving the probe across the surface of the
workpieceyoucanobtainacrosssectionalprofileofyourpart.Thisallowsforviewingthecontourof
yourpart. 
When youremove the probe from the workpiece, the gauge can obtain the minimum value of the B
scanimageandindicatethatpositionwithaREDarrow.YoucanseeanypointthicknessvalueoftheB
scanimagebymovingthepointertoanyposition.
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3.8DUAL‐ECHO(THRU‐COATING)MODE
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The UTG‐4000 can accurately measure the actual material below the coating utilizing the dual echo
measurementprinciple.Thisfeatureallowsyoutomeasurethematerialwithouthavingtodestroyor
removetheprotectivecoatingofasurface.
Press“M”togointotheparameterinterfaceandsetMeasurementmodetoDUAL‐ECHOandpress“M”
toreturntothemainmeasurementscreen.
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3.8.1A‐Scaninterfaceindual‐echomode
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TheUTG‐4000allowsyoutouseA‐scanwhileinthedual‐echomode.ThisfeaturehasaddedE‐blanking
optionaswellastheoptiontocancelGATE.Whenmeasuring,thebluestripareaindicatesthelengthof
echoblanking./thewaveformabovethisisconsideredinvalid.
Seefig3.16below:
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1) Identificationofdual‐echomode
2) Bluearrowindicatessecondaryecho
3) E‐blanking
4) Blueline:thelengthofecho‐blanking
5) Redline:lengthofinitialblanking
6) Redarrow:indicatesfirstecho
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BlankinginDual‐EchoMode:
a) Initialblanking:Theredblankinglinestartsatzero.Thewaveformwithinthescopeofthered
stripisconsideredinvalidduetolackofclutterbetweenthestartingpointandthefirstecho.
b) E‐Blanking(echoblanking):thebluelineindicatedonthescreenappearswhenameasurement
has been successfully taken. This linestarts at the first echomeasurementpoint.Awaveform
withinthescopeofthebluestripeisalsoconsideredinvalidduetolackofclutterbetweenthe
firstechoandsecondaryecho.
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4.DATASTORAGEFUNCTIONS
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TheUTG‐4000utilizesamicrogridformatallowingthisunittostoreupto100,000thicknessvalues
and1,000A/Bscanwaveforms.SeeFig3.17below
Thickness values and waveforms can be mixed and stored in the same file. The stored data can be
transferredtoyourPCviaUSBoutputandsavedasanEXCELorTXTfile.
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4.1THICKNESSVALUEANDWAVEFORMSTORAGE
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1) Storagefilenumber
2) Linemark
3) Rowmark
4) Datainmemory
5) Returntomainmenu
6) Savecurrentvalueorwaveform
7) Deletetheselecteddata
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4.2Browsingstoreddata
Press“M”toentertheconfigurationdisplay.Highlight“GRIDFILE”andpresstheP1buttontoselect.
Usetheupanddownarrowstochoosethedatayouwanttorecall.PresstheCAL/ONbuttontoconfirm.
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5.CAREANDMAINTENANCE
5.1POWERSOURCEINSPECTION
During the usage of the gage, the current battery power will beshownonthedisplay.Whenthe
battery power is low, the customer should change the batteries promptly so that the measuring
accuracywon’tbeinfluenced.Thestepsofchangingbatteriesareasfollow: 
1. Turnoffthegage.
2. Loosenthescrewsonthebackoftheunitandremovethebatterycover.
3. Takeoutthebatteriesandreplacewithnewones.Paycarefulattentiontopolarity. 
Attention:whennotusingthegaugeforextendedperiodsoftime,pleaseremovebatteriestoprevent
anyleakageorcorrosion.  
5.2Maintenance:
1. Alwayskeepyourgauge,probe,cablecleanofanydirt,dust,fluids,etctopreventearlywearofthese
parts.
2. Besuretoavoidanycausticliquidsuchasalcoholorviscousfluidstopreventcorrosiontothecover
andthedisplaywindow.Cleanwithwateronly.
3. Avoidscratchingthesurfaceoftheprobe.Awornprobewillcauseunstablereadings.
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5.3Service/Support
ContactPhaseIIforalltechnicalsupportand/orservice.
Tosendyourunitinforanytypeofservice,pleasecallforaRMA#.
(201)962‐7373


ApplicationsNotes:
Measuringpipeandtubing.
Whenmeasuringapieceofpipetodeterminethethicknessofthepipewall,orientationofthe
transducers is important. If the diameter of the pipe is larger than approximately 4 inches,
measurementsshouldbemadewiththetransducerorientedsothat the gap in the wearface is
perpendicular (at right angle) to the long axis of the pipe. For smaller pipe diameters, two
measurements should be performed, one with the wearface gap perpendicular, another with the gap
paralleltothelongaxisofthepipe.Thesmallerofthetwodisplayedvaluesshouldthenbetakenasthe
thicknessatthatpoint. 

Measuringhotsurfaces
  Thevelocityofsoundthroughasubstanceisdependantuponitstemperature.Asmaterialsheatup,
thevelocityofsoundthroughthemdecreases.Inmostapplicationswithsurfacetemperatureslessthan
about100,nospecialproceduresmustbeobserved.Attemperaturesabovethispoint,thechangein
sound velocity of the material being measured starts to have a noticeableeffectuponultrasonic
measurement. Atsuchelevatedtemperatures,it is recommendedthat the user performa calibration
procedureonasamplepieceofknownthickness,whichisatornearthetemperatureofthematerialto
bemeasured.Thiswillallowthegaugetocorrectlycalculatethe velocity of sound through the hot
material. 
 Whenperformingmeasurementsonhotsurfaces,itmayalsobenecessary to use a specially
constructedhigh‐temperaturetransducer.Thesetransducersarebuilt using materials which can
withstand high temperatures. Even so, it is recommended that the probe be left in contact with the
surfaceforasshortatimeasneededtoacquireastablemeasurement.Whilethetransducerisincontact
withahotsurface,itwillbegintoheatup,andthroughthermalexpansionandothereffects,maybegin
toadverselyaffecttheaccuracyofmeasurements. 
Measuringlaminatedmaterials.
Laminatedmaterialsareuniqueinthattheirdensity(andtherefore sound‐velocity) may vary
considerablyfromonepiecetoanother.Somelaminatedmaterialsmayevenexhibitnoticeablechanges
insound‐velocityacrossasinglesurface.Theonlywaytoreliablymeasuresuchmaterialsisby
performingacalibrationprocedureonasamplepieceofknownthickness.Ideally,thissamplematerial
should be a part of the same piece being measured, or at least fromthesamelaminationbatch.By
calibratingtoeachtestpieceindividually,theeffectsofvariationofsound‐velocitywillbeminimized.


An additional important consideration when measuring laminates,isthatanyincludedairgapsor

pocketswillcauseanearlyreflectionoftheultrasoundbeam.This effect will be noticed as a sudden
decreaseinthicknessinanotherwiseregularsurface.Whilethismayimpedeaccuratemeasurementof
totalmaterialthickness,itdoesprovidetheuserwithpositiveindicationofairgapsinthelaminate.

Suitabilityofmaterials
Ultrasonicthicknessmeasurementsrelyonpassingasoundwavethroughthematerialbeingmeasured.
Not all materials are good at transmitting sound. Ultrasonic thickness measurement is practical in a
widevariety of materials includingmetals, plastics,andglass.Materialsthataredifficultincludesome
castmaterials,concrete,wood,fiberglass,andsomerubber.


Couplants
Allultrasonicapplicationsrequiresomemediumtocouplethe soundfromthetransducertothe
test piece. Typically a high viscosity liquid is used as the medium. The sound used in ultrasonic
thicknessmeasurementdoesnottravelthroughairefficiently. 
Awidevarietyofcouplantmaterialsmaybeusedinultrasonicgauging.Propyleneglycolissuitable
formostapplications.Indifficultapplicationswheremaximumtransfer of sound energy is required,
glycerinisrecommended.However,onsomemetalsglycerincanpromotecorrosionbymeansofwater
absorptionandthusmaybeundesirable. 
Othersuitablecouplantsformeasurementsatnormaltemperaturesmayincludewater,variousoils
and greases, gels, and silicone fluids. Measurements at elevated temperatures will require specially
formulatedhightemperaturecouplants.
Inherentinultrasonicthickness measurement is the possibility that the instrument will use the
secondratherthanthefirstechofromthebacksurfaceofthematerial being measured while in
standardpulse‐echomode.ThismayresultinathicknessreadingthatisTWICEwhatitshouldbe.The
Responsibilityforproperuseoftheinstrumentandrecognition of these types of phenomenon rests
solelywiththeuseroftheinstrument.

Allvelocitiesareapproximations:
SOUNDVELOCITYMEASUREMENTCHART
MaterialSoundVelocity
Inch/µSM/s
Air 0.013 330
Aluminum 0.250 6300
AluminaOxide 0.390 9900
Beryllium 0.510 12900
BoronCarbide 0.430 11000
Brass 0.170 4300
Cadmium 0.110 2800
Copper 0.180 4700
Glass(crown) 0.210 5300
Glycerin 0.075 1900
Gold 0.130 3200
Ice 0.160 4000
Inconel 0.220 5700
Iron 0.230 5900
Iron(cast) 0.180 4600
Lead 0.085 2200
Magnesium 0.230 5800
Mercury 0.057 1400
Molybdenum 0.250 6300
Monel 0.210 5400
Neoprene 0.063 1600
Nickel 0.220 5600
Nylon,6.6 0.100 2600
Oil(SAE30) 0.067 1700
Platinum 0.130 3300
Plexiglass 0.110 1700
Polyethylene 0.070 1900
Polystyrene 0.0930 2400
Polyurethane 0.0700 1900
Quartz 0.230 5800
Rubber,Butyl 0.070 1800
Silver 0.140 3600
Steel,Mild0.2335900
Steel,Stainless 0.230 5800
Teflon 0.060 1400
Tin 0.130 3300
Titanium 0.240 6100
Tungsten 0.200 5200
Uranium 0.130 3400
Water 0.584 1480
Zinc 0.170 4200