Ut Thickness

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HELLIER

WELCOME TO THE
UT THICKNESS
COURSE







24 Hour Course.
Class Hours: 8:00am to 4:30pm.
Breaks: At the discretion of the instructor.
Lunch: 1 hour - 11:30 - 12:30
Restrooms:
Safety:
HELLIER

COURSE OBJECTIVES
• Purpose: Present the body of knowledge of
Ultrasonic Thickness Testing
• Objective: Impart an understanding of the
following topics of UT Thickness Inspection






Principals and Theory
Equipment and Materials
Techniques and Calibrations
Inspection Variables
Procedures and Specifications
HELLIER

STUDENT OBJECTIVES


Purpose: Learn the body of knowledge
for Ultrasonic Thickness Testing



Objectives: To achieve an
understanding of UT thickness
inspection and a proficiency in using
portable ultrasonic thickness gages for
taking thickness measurements.

HELLIER

LET’S GET ACQUAINTED.





Name:
Company:
Job Title:
Background:

HELLIER

CLASS FORMAT
• Instructor led presentation of information
• Informal open discussion
Ask pertinent questions
Be respectful of others

HELLIER

PERSONNEL CERTIFICATION









SNT-TC-1A
NAS 410
CP 189
ISO 9712
ACCP
CSWIP
CGSB
AWS-NDE

Employer Certification

Central Certification

HELLIER

NDT PERSONNEL
QUALIFICATION AND
CERTIFICATION
Recommended Practice SNT-TC-1A:
• Guidelines for NDT PQ&C to assist the
employer
• Published by ASNT
• Uniform procedures for the qualification and
certification
• Satisfy the employer's specific requirements.
HELLIER

QUALIFICATION AND
CERTIFICATION

HELLIER

NDT NAMES
• NDT – Nondestructive Testing
• NDI – Nondestructive Inspection
• NDE – Nondestructive Examination or
Evaluation
• Common Names – Zyglo test, Magnaflux
test, Sonic test, etc.

HELLIER

ELEMENTS OF A
NONDESTRUCTIVE TEST






Source which provides a probing medium
Changes to the probing medium
Detect the changes
Record or indicate the changes
Interpret the cause of the changes
HELLIER

DEFINITIONS
• Indication - Response from an NDT Test
– False - Caused by improper technique;
usually not repeatable
– Non-relevant - Condition in the part;
intentional or unintentional
– Relevant - Unintentional discontinuity in
the part
• Discontinuity - An interruption in the
physical structure of the test piece that
may be intentional or unintentional
HELLIER

DEFINITIONS
• Flaw – An unintentional discontinuity, an
imperfection; which may, or may not be,
rejectable
• Rejectable Discontinuity - A flaw related to
a relevant indication that exceeds the
acceptance criteria; a rejectable, relevant
indication.
HELLIER

DEFINITIONS
• Defect – a discontinuity that will cause the
part not to be used for it’s original purpose.
A condition that will render the part not
useable or that could cause part failure or
malfunction

HELLIER

NDT Interpretation/Evaluation Flowchart
Indication
Evaluation
False?

No

NonRelevant?

Yes

Interfere
with
Inspection?

Yes

No

No

Relevant
Indication

Interpretation

Ignore
No

Violate
Acceptance
Criteria?
Use?

Yes

Re-Process

Yes

Accept

HELLIER

Reject

MAJOR NDT METHODS
VT
PT
MT
UT
RT
ET

AE
NRT
TIR
AE
VA
Laser Methods
HELLIER

ADVANTAGES OF NDT
• All of these methods of NDT share some
common advantages:
– Increased product reliability
– Increased product safety
– Increased productivity
– Increased profitability
– Increased product serviceability
– Minimized product liability
HELLIER

ADVANTAGES OF NDT
• However, they also share a common
limitation:
The NDT method applied, regardless of
the equipment and materials used, will
only be as effective as the inspector skill
allows. It is not a panacea!

HELLIER

ULTRASONIC INSPECTION
Inspection method using sound
• Introduces high frequency sound
waves into test object.
• Measures two quantities:
•time for sound to travel.
•amplitude of received signal.
HELLIER

HISTORY
• 1880 Curie brothers discovered piezoelectric
principle.
• Certain crystals develop a voltage when
pressure is applied.
• 1881 Lippman discovered the piezoelectric
principle operates in reverse.
• Piezoelectric crystals will change shape
when a voltage is applied.
HELLIER

HISTORY (CONTINUED)


1929 Sokolov performed thru-transmission.
•Continuous wave travels through material
under test.
•Displays transmitted and received signals.

HELLIER

HISTORY (CONTINUED)
1941 Floyd Firestone (US) and James
Sproule (England) developed pulse - echo test
instruments.
• Echoes reflected from material boundaries
and discontinuities provide test signals.


HELLIER

UT THICKNESS APPLICATIONS
Discontinuity detection.
Thickness measurements.
• Corrosion/Erosion.
• Pipe Wall Thickness.
• Vessel Wall Thickness.
• Plastics
• Precision Measurements

HELLIER

UT - ADVANTAGES


Deep penetration into material.

• Portable equipment: battery powered.
• Pulse echo requires one sided accessibility only.
• Accurate for thickness measurement and
discontinuity location.
• Permits volumetric examination.
• Suitable for go/no-go testing: audible & visible
alarms.
• No known hazards

HELLIER

UT - LIMITATIONS


Test object must be able to conduct sound.
• Fine grained, elastic material.

• Liquid couplant is required.
• Requires a trained operator.
• Discontinuities just below surface may not be
detected.
• Dead Zone
HELLIER

WHAT IS SOUND



Mechanical energy
propagating through a
material in the form
of pressure waves.
HELLIER

GENERATION OF SOUND
UT instrument produces an electrical pulse
Transducer:
• Converts electrical pulse to sound energy.
which travels through the material
• Returning echoes are converted back into
an electrical signal
UT instrument processes the returning
signals for display
HELLIER

ULTRASONIC TESTING
Ultrasonic Transducer
• Like a speaker when transmitting;
• Like a microphone when receiving
Piezoelectric Effect:
 Apply electrical energy, mechanical
energy is produced
 Apply mechanical energy, electrical
energy is produced
HELLIER

PIEZOELECTRIC EFFECT
When exposed to an alternating current an element expands and contracts

-

+

+

-

HELLIER

-

+

WAVE MOTION
The pressure in the sound waves displace
the molecules in the material.
• Various wave modes can be generated.

Longitudinal, Shear, and Surface


Wave modes are defined by their particle
motion relative to direction of sound wave
travel.
HELLIER

VELOCITY OF SOUND
The speed that sound goes through a
medium.
Depends on two material properties:
• Density: How tightly packed
are the
molecules.
• Elasticity: Restoring force of the electrical
bonds.
And the Type of
the Sound Wave
HELLIER

VELOCITY
Measured in distance travelled per unit of time.






Inches/second (in/sec)
Inches/microsecond (in/sec)
Kilometers/second (km/sec)
meters/second (m/sec)
centimeters/microsecond (cm/sec)

Velocity is affected by temperature
HELLIER

LONGITUDINAL WAVES
• Also known as Compressional Waves
• Particle Vibrations parallel to the direction
of wave propagation.

Propagation
Particle vibrations
HELLIER

LONGITUDINAL WAVES
• Alternating zones of compression (high
pressure) and rarefaction (low pressure)
Propagation

Particle vibration
• Travel in solids, liquids and gases.

• Highest velocity of all wave modes.
HELLIER

SHEAR WAVES
• Vibrations at right angles to the direction of propagation.
• Finds flaws not parallel to the surface

Not used with thickness gages
Particle vibration

Propagation
HELLIER

SURFACE WAVES
• Elliptical vibrations
• Special wave at the surface of the part
• Finds cracks and scratches
Not used with thickness gages

HELLIER

SOUND WAVE MEASURMENTS
• Cycle: A complete repetition of particle
motion
• Frequency: Number of cycles of vibration
per second
• Wavelength: Distance the sound wave
travels during a cycle

HELLIER

FREQUENCY
• Frequency Ranges:
– Audible range: 20 to 20,000 Hz.
– Ultrasound: above 20,000 Hz.
– Commercial testing: 100 kHz to 25 MHz.

• Frequency units:
– Hertz (Hz): cycle per second.
– Kilohertz (KHz): thousand cycles per second.
– Megahertz (MHz): million cycles per second.
HELLIER

WAVELENGTH


Distance sound travels during one cycle.

Measured from one point on cycle to an
identical point on the next cycle.
λ

λ
HELLIER

WAVELENGTH / FREQUENCY


V = f × λ

V

f

V = velocity
f = frequency
λ = wavelength

Frequency and wavelength are inversely
proportional
• frequency increases, wavelength decreases
• frequency decreases, wavelength increases
HELLIER

SOUND BEAM GEOMETRY
Near
Field
Intensity
varies

Far
Zone

Yo
Beam Diverges
(Spreads)

Distance
HELLIER

SOUND BEAM AREAS
• Near Field:
• Far Field:
• Yo (Near Field Length): Distance

HELLIER

THE SOUND BEAM
• The length of the near field can be
calculated from the following formula:

D  ff
D
NN 4  V
4 V
22

Where:

N = Near Field Length (mm)

f = Frequency (MHz)

D = Crystal Diameter (mm)

V = Velocity (Km/sec)
HELLIER

NEAR ZONE
2

D
Near Zone 
4

2

D f

4V

• The larger the diameter the longer the
near zone
• The higher the frequency the longer the
near zone
• The lower the velocity the longer the near
zone
HELLIER

THE SOUND BEAM
• Beam Divergence can be calculated from
the following formula:

Where:

 1.22  V 
  arcsin 

 D f 

 = Beam Divergence Angle

f = Frequency (MHz)

D = Crystal Diameter (mm)

V = Velocity (Km/sec)
HELLIER

BEAM SPREAD

 K
KV
Sine 
or
2 D
Df
• The larger the diameter the less the beam spread
• The higher the frequency the less the beam spread
• The lower the velocity the less the beam spread

HELLIER

ATTENUATION
• Material Loss Attenuation:
•Scattering of sound by grain structure of
the material.
•Conversion of sound energy into heat
• Sound amplitude lost due to:
•Attenuation
•Beam Spread.
HELLIER

SOUND AT AN INTERFACE
Interface: Boundary between two materials
Incident Wave

Reflected

Interface

Interface

Transmitted

At an acoustic interface sound will be reflected
and/or transmitted across the interface
HELLIER

ACOUSTIC INTERFACE
• Boundary between two materials with
different acoustic impedance values.

• The amount reflected
and transmitted
depends upon the
acoustic impedances
of the two materials.

Reflected
Acoustic
Interface

Transmitted
HELLIER

ACOUSTIC IMPEDANCE (Z)
Impedance: Opposition a material offers to the
propagation of sound travelling through the
material.
• The greater the ratio (mismatch) between the
two impedances of the materials,
• The greater the percentage of sound reflected.

Z=Vx
V = Velocity

= Density
HELLIER

REFLECTION PRINCIPLES
Formula for reflected energy (RE):
2

 Z 2  Z1 
  100
% RE  
 Z 2  Z1 
Z1 = impedance of the first material the sound is in
Z2 = impedance of the material the sound reaches
Note: Due to the Law of Conservation of Energy
Transmitted Energy = 100% - Reflected Energy
HELLIER

TRANSDUCER DESIGNS FOR
THICKNESS GAGING


Single crystal: materials > 1/2” thick.

• Dual crystal: corroded and eroded
materials.
• Delay line: thin materials with parallel
surfaces.

HELLIER

CONTACT TRANSDUCER
DESIGN


Crystal thickness determines frequency of
vibrations.

• Electrodes establish electrical contact
with the crystal.
• Wear plate provides protective contact
surface.
• Damping controls crystal ringing;
absorbs rear sound waves.
HELLIER

SINGLE ELEMENT
TRANSDUCER
Electrical
Leads

Connector

Electrical
Network

Inner
Sleeve

External
Housing

Backing

Active
Element

Electrodes

Wear
Plate

• Used on thicker materials; > 1/2”.
HELLIER

DUAL ELEMENT TRANSDUCER
Transmitting
Element

Acoustic
Barrier

Receiver
Element

Connector

External
Housing

Delay
Material
Test Sample

Angular
Sound
Path

Thickness gaging of corroded and eroded
materials.
HELLIER

DUAL CRYSTAL
Sound beam is reflected and refracted into
the receiving element
Transmitter Receiver

Used to detect reflectors
approximately parallel
to test surface.
Measure: Thickness
Corrosion
Erosion
HELLIER

DUAL ELEMENT TRANSDUCER
Sound reflecting off of bottom of test piece
back into the transmitting side of the
transducer.
Material is too thin for the transducer

This is referred to as DOUBLING.
HELLIER

DUAL ELEMENT TRANSDUCER
Sound reflecting off of bottom of test piece
reflects beyond the receiving side of the
transducer.
Material is too thick for the probe
Mode Conversion occurs
Shear Wave gives the
thickness readout.
1 ½ TIMES THICKNESS
HELLIER

DELAY TRANSDUCER
• Introduces sound perpendicular (normal) to the test surface.


Improves near surface resolution.
• Detection

of discontinuities near test surface.
• Thickness measurement of thin materials
Electrical connectors

Crystal

Plastic delay tip

Damping
HELLIER

ULTRASONIC INSTRUMENT
FUNCTIONS
• The instrument contains six basic sections:

HELLIER

INSTRUMENT FUNCTIONS
• Connecting a probe and coupling it to the
test object completes the test system

HELLIER

INSTRUMENT FUNCTIONS
The Power Supply provides voltage from the
AC or batteries to drive the other instrument
circuits

HELLIER

INSTRUMENT FUNCTIONS
• The clock initiates the chain of events that
results in one complete cycle of an
ultrasonic test

HELLIER

INSTRUMENT FUNCTIONS
• The clock emits s trigger signals, repeated
at the pulse repetition frequency (PRF)
• Depending on instrument, the PRF may be:
– Set by the operator
– self-adjusting/ or both

• The proper PRF depends on the part
thickness
• When PRF is too fast, wraparound (display
of echoes from previous test cycles) occurs
HELLIER

INSTRUMENT FUNCTIONS
• The clock triggers the Timebase and Pulser 
at regular, evenly spaced intervals

HELLIER

INSTRUMENT FUNCTIONS
• The timebase initiates time/distance display 
on the instrument’s horizontal scale
– used for distance readout

HELLIER

INSTRUMENT FUNCTIONS
• The pulser sends initial pulse to transducer, 
causing sound to enter the test object
– initial pulse goes through the Receiver/Amplifier 
to the display

HELLIER

INSTRUMENT FUNCTIONS
• The Initial Pulse is a fast rising, high
voltage pulse that activates the transducer
• Duration of transducer ringing determines
the length of the dead zone
• Dead zone is the depth range in the test
material where relevant indications are
hidden inside the Initial Pulse’s indication
HELLIER

INSTRUMENT FUNCTIONS
• Sound travels through the test object as
time elapses along the display

HELLIER

INSTRUMENT FUNCTIONS
• Sound reflects from material boundaries 
and discontinuities

HELLIER

INSTRUMENT FUNCTIONS
• Transducer echo voltage is processed by the 
receiver and displayed

Echo height is determined by reflected sound
HELLIER

INSTRUMENT FUNCTIONS
• Time base Controls
– Zero Offset Control
• adjusts when the horizontal display starts
relative to the activation of the initial
pulse
– Range Control
• adjusts the amount of time displayed
along the horizontal scale to correspond
with sound travel time through a specific
thickness of material
HELLIER

INSTRUMENT FUNCTIONS
• Time base Controls
– Velocity Control
• adjusts the amount of time displayed
along the horizontal scale to
correspond with sound travel time
through material of a particular
velocity

HELLIER

INSTRUMENT FUNCTIONS
• Pulser Controls
– Pulser Energy Control
• adjusts the size of the Initial Pulse
– Damping Control
• adjusts transducer performance for
resolution versus penetrating power
Note: Both Pulser Energy and Damping
affect duration of the dead zone
HELLIER

INSTRUMENT FUNCTIONS
• Receiver processes and amplifies signals
going to the Display
– Processing is provided by detector and
filter sub-circuits
• Detector sub-circuit can provide choice of
various types of signal passing through the
receiver – RF or Selected video mode
HELLIER

INSTRUMENT FUNCTIONS
Comparison of RF and all Video modes

Negative half is often used to present a more
narrow echo (better resolution) for thickness
testing
HELLIER

COUPLANTS
• Liquid (usually) used to exclude air from
the path of the sound beam.
• Considerations
• Wetting Ability
• Viscosity
• Reactivity
• Ease of removal
• Expense
HELLIER

TYPICAL COUPLANTS


Water

• Oil
• Cellulose and water mixture
• Grease/Petroleum Jelly
• Commercially prepared
•High temperature couplants
HELLIER

THICKNESS INSPECTION
Thickness inspection incorporates:
• Pulse Echo Technique
• Resonance Method
Measurements are made of:
• Thickness of new parts
• Erosion / Corrosion
HELLIER

THICKNESS CONSIDERATIONS






Calibration procedure should be followed
Couplant should be thin as possible
Part surfaces should be smooth
Part surfaces should be parallel
Gage gives reading of first large echo
– Need to verify actual reflector at times
– A-Scan Gages provide this verification
HELLIER

THICKNESS CONSIDERATIONS
• Use two point calibration when possible
• Calibration block
– Known, documented NIST thickness
– Same material as part being inspected
– Similar temperature to the part

• High temperature increases part thickness
• Insure “new” reading for each location
HELLIER

SOUND TRAVEL GEOMETRY
• Digital Thickness gages measure distances to
reflectors which are parallel to the part’s
surface
– Straight beam transducer
– Dual Element transducer
– Delay Transducer

HELLIER

BASIC TEST TECHNIQUE
PULSE-ECHO
• Test object information provided by
reflected sound energy
• Individual echo signal for each reflector
perpendicular to beam axis

HELLIER

BASIC TEST TECHNIQUE
PULSE-ECHO
• Displayed Information: echoes reflected
from acoustic interfaces

HELLIER

BASIC TEST TECHNIQUE
RESONANCE
• Resonance tests are used for thickness
measurements
– Continuous wave of variable frequency
– Resonance occurs when material
thickness equals 1/2 of wavelength
– Has been replaced by pulse-echo method
– Still used in aerospace for thickness
readings and bond-testing
HELLIER

BASIC TEST TECHNIQUE
RESONANCE
• Displayed Information is derived from
fundamental and harmonic frequencies

HELLIER

DATA PRESENTATION
• Display hardware
– Electro-luminescent displays
– Liquid crystal displays
– Paper chart recorders
– Digital readouts
– Computer screens
HELLIER

DATA PRESENTATION
• A-scan
– horizontal scale:
displays time to
indicate distance
– vertical scale:
displays
transducer output
voltage to indicate
echo amplitude
HELLIER

DATA PRESENTATION
• Digital Readouts
• B-scan
Side view of test object:
profile of interfaces
reflecting sound beam
– Immersion Testing
– Digital Thickness Gages
– Computer Applications
HELLIER

TIME/DISTANCE
RELATIONSHIP


Velocity is different in different materials

• Accurate calibration is crucial
• Gage converts travel time to thickness

Thickness =

(Velocity) (Time)
2
HELLIER

THICKNESS GAGING
• Uses High Frequency Sound Waves
– Typically 5.0 MHz thru 20.0 MHz
– Longitudinal Sound Energy
• Thickness Measurement From One Side
• Nondestructive
HELLIER

PRECISION THICKNESS
GAGING

• Single Element Transducers

• Highly Damped, Delay Transducers
• Provides High Degree Of Accuracy
• New Materials for Quality Control
– Metals, Plastics, Glass and Composites
HELLIER

CORROSION THICKNESS
GAGING
• Uses Dual Element Transducers
• Erosion/Corrosion
• Typically on Metal
• Irregular/Pitted Reflecting Surface

HELLIER

DUAL ELEMENT
TRANSDUCER ON CORRODED
MATERIAL
TX RX

• Roof angle focuses sound at the base of
pits.
HELLIER

SINGLE ELEMENT
TRANSDUCER ON
CORRODED MATERIAL

• Much of the sound is scattered away from
the transducer.
HELLIER

DUAL ECHO AMPLITUDES
TX RX

• First Echo is not
always the Largest
• Due to:
– Roof Angle
– Thickness
– Material Velocity
– Delay Material

First
Backwall
Echo
Second
Backwall
Echo

2 nd Echo
1 st Echo

HELLIER

DUAL ELEMENT
ADVANTAGES
• Roof Angle narrows the beam for pits
• High Temp. capabilities (≈ 1,000° F)
• Separate Elements
– Use Higher Initial System Gain
– Better near surface Resolution
– Stable Readings on Rough Entry Surfaces
HELLIER

CHOOSING TRANSDUCERS
• Material
– Carbon steel
– Cast material
– Aluminum

• Thickness Range
– Min and Max thickness

• Geometry
– Min Diameter
– Convex/Concave Surface
– Surface Condition
HELLIER

TRANSDUCER CRITERIA
• Frequency
– Higher Frequency -- Better Resolution
– Higher Frequency -- Better Sensitivity

• Roof Angle
– Steeper Angle Will Have Shorter Focus

• Delay Material for High Temperature
HELLIER

THICKNESS GAGING
PERFORMANCE VARIABLES
• Penetration: Ability to pass through a
material interface.
– Improves with longer wavelength.
• Wavelength increased by decreasing
frequency.

HELLIER

THICKNESS GAGING
PERFORMANCE VARIABLES
• Resolution: Ability to individually
display reflectors located at slightly
different depths along the sound beam.
– Resolution increases with an increase
in bandwidth and/or frequency.
HELLIER

ZERO OFFSET ERROR
Caused by Built In Test Block
ZERO
OFFSET

Worn
Probe
on Zero
Incorrectblock
Zero

Zero
Block



ZERO
OFFSET

ZERO
OFFSET

Worn Probe
on Curved
Pipe

Offsets
– With Worn Transducers
– On Curved Surfaces
– On Rough Surfaces

HELLIER

Rough
Surface

AUTO PROBE RECOGNITION
• Optimizes setup and receiver gain.
• Transducer V-Path correction.
• Accurate measurements over large thickness
ranges.
TX

RX

Sample
True
Thickness

Angular
Sound Path

HELLIER

AUTO ZERO COMPENSATION
•Uncouple and Press Zero Key to:
– Measures Time Through
Transducer
– Tracks Transducer Wear
– Compensate For Thermal
Drift At Elevated

Rx
Delay

Temperatures
HELLIER

Tx
Delay

ECHO-TO-ECHO
Sound
Entry

1st ECHO

2nd ECHO

2 METAL+2C

3rd ECHO
2 METAL

2 METAL

COATING

COATING

COATING

COATING

2 METAL
Coating

Metal

Standard
Measurment
Echo-to-Echo
Measurment

=

Total Thickness
Coating and Metal

[1 Coating]+[1 Metal] + [1 Metal] + [1 Coating]
2
=

[ -1 Coating

]+[1 Metal] + [1 Metal] + [1 Coating]
2

HELLIER

Thickness of
Metal Only

AUTOMATIC ECHO-TO-ECHO

• No Gates To Set
• Gage Automatically Finds The Two Highest Back wall Signals
• Marker Indicates Detected Echoes
• Users Verifies Proper Detection

HELLIER

MANUAL ECHO-TO-ECHO

• User Selects Detection By Adjusting:
– Signal Amplitude
– Blanking Gate

HELLIER

TWO POINT CALIBRATION
Cal
Velocity
Enter Max Sample Thickness

Cal Zero

Enter Min Sample Thickness

• Try to Calibrate On Actual Samples
– Having The Same Surface Conditions
– Same Geometry
– Same Material
HELLIER

THICKNESS GAGE
ADVANTAGES









Size and Cost
Ease of Calibration and Operation
Auto Probe Recognition
V-Path Correction
Auto Zero Compensation
Greater Data Logging Capability
Thru Paint Echo-to-Echo Measurements
Better Thickness Accuracy
HELLIER

THICKNESS ACCURACY
• Thickness measurement accuracy using
A-Scan gages is dependent on:
Detection
Flanking Gate Detection
Peak Gate Detection
Screen Resolution
Number of Pixels
HELLIER

FLANKING GATE DETECTION
• Accuracy Affected By:
– Coupling Pressure
– Echo Amplitude
– Leading Edge Shape
– Transducer Alignment
– Front Surface Condition
– Backwall Surface Condition
– Material Properties

SIGNAL
AMPLITUDE
AT 50dB
SIGNAL
AMPLITUDE
AT -6 dB
THRESHOLD
GATE

Detection 1
Detection 2

HELLIER

PEAK DETECTION
• Dual Signals Have Multiple

PEAK
SIGNAL

Peaks

PEAK
GATE

• Peaks Change Due To:






Transducer Alignment
Surface Condition
Coupling Pressure
Backwall Surface Condition
Grain Structure

• Peak Detection Is Less Sensitive
to pits

HELLIER

TIME TO
PEAK
PEAK
SIGNAL

PEAK
GATE

TIME TO
PEAK

ALGORITHMS AND DSP

• Leading Edge of Echo is Automatically
Detected
• Calibrated Accuracy Maintained When Gain
Is Adjusted
• System Runs At Lower Gain And Yields A
Cleaner Waveform
HELLIER

THE WAVEFORM
ADVANTAGE
Disbond

• Voids, Disbonds And Flaws Can Cause Internal
Reflections
Problem

Disbond Detected

Solution

Disbond Reflection
HELLIER
Blanked Out

SURFACE NOISE
Rough Surface

Aluminum

• Sound energy reflects from rough surfaces
and high impedance materials.
Problem

Reading Surface
Reflections

Solution 1

Solution 2

Surface Noise
Blanked Out

Reduce Gain

HELLIER

GRAIN REFLECTION
• Large Internal Reflections
From Grain Boundaries
Can Cause False Readings
Problem

Reading Grain
Noise

Solution 1

Grain Noise
Blanked Out
HELLIER

Solution 2

Reduce Gain

FEATURES FOR
HIGH TEMP APPLICATION






Gain Adjust (Add Gain )
Fast Update Rate (20 Reading/Sec)
Freeze Waveform
Probe Zero (Correct for Thermal Drift)
Save Data
– Waveform
– Thickness
– Gain Settings

HELLIER

HIGH TEMPERATURE
COUPLING TECHNIQUES

• Use Appropriate Couplant for Temp Range

– F-2 Medium Temps Below 260oC (500o F)
– E-2 High Temp For 260 - 500oC (500-1000o F)
• Apply Couplant To Transducer Tip
• Use Firm Coupling Pressure
• Limit Contact Time To Five Seconds
• Wipe Transducer And Press Zero Key To
Compensate For Transducer Drift
HELLIER

ENSURE
TRANSDUCER LONGEVITY
• Limit Transducer Contact Time to Five Seconds
• Never Let Transducer Get To Hot To Hold
• If Transducer Gets Hot
– Cool in Air
– Dip Tip in Water
– Re-Zero
• Avoid Dragging Transducer Cable Across Pipe
HELLIER

DATALOGGER INPUT
PRE-LOAD

HELLIER

BARCODE WAND
• Plugs Into RS-232 Port
• Reads Standard 3 of 9
(39) Labels

ID:TML 1.00
THk: 0.286

*

• Internal Barcode
BAR CODE WAND

Software Is Standard

0.267

on All 26DL PLUS’S
HELLIER

BARCODE WAND
• Scan Barcode Tags
TML: 4.00
0.236

From Drawings
• Scan Barcode Tags
Located On The

TML: 6.00
0.285

TML: 9.00
0.210

TML: 1.00
0.200

TML: 2.00
0.225

TML: 3.00
0.205

Equipment

TML: 5.00
0.241

DESCRIPTION: REBOILER #3, BLD 142N
DATE: 9/16/96 DRAWING: # 85236
REV: C

TML: 7.00
0.300

TML: 8.00
0.310

TML: 10.00
0.231

COMPANY: XYZ CORPORATION

• Build Files As You Go
• Jump To Scanned Location In Pre-loaded
File
HELLIER

INTERFACE PROGRAMS





Usually free with gage purchase
Bi-directional communication
Some use standard ASCII data
Store data for future on version/import into:
– Other inspection programs
– Word processing software
– Spread sheet programs
HELLIER

INTERFACE PROGRAMS
• Print/Read Files and Waveforms
• Edit Files
• Produce Color Reports
• Create/Load Different File Formats
• Create Statistics Reports

HELLIER

INTERFACE PROGRAM
STATISTICS
Identifier

Thickness

HELLIER

COLOR CODED FILE
PRESENTATION

Easy Conversion Of Boiler And Grid Files
Up To Seven Different Ranges And Colors
Change Display Size and File Orientation
Show Colors only
HELLIER

OTHER DATA
MANAGEMENT PROGRAMS
Name

Manufacturer

Country



Credo

Chartex Software

UK



Cortran

Rios Software

UK



DataMate

Krautkramer

USA



UltraPipe

Krautkramer

USA



EMPRV

EDS (under development)

USA



EPRI Check/Works

EPRI

USA



IDM

Exxon

USA



Meridium

(under development)

USA



PIPE Sys

Atomic Software

UK

HELLIER

Keyboard Lock
• Press
6

3

Allows the operator to
lock all keys except
ON/OFF and DIFF

Simultaneously

Press again to un-lock the keyboard.

HELLIER

Change Hold/Blank
• Press and Hold
Allows the operator
2
to switch between
the display HOLD and
Then Press the display BLANK
conditions when no
MEAS
measurement is
being made (LOS).
and release both

HELLIER

HELLIER

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