all techniques - in brief

8/6/2019 All Techniques - In Brief

http://slidepdf.com/reader/full/all-techniques-in-brief 1/87

1

Ultrasonic C-Scan VideoCorrosion Mapping



2

Corrosion Mapping

Principles of Video Corrosion Mapping

Real time colour graphic images of corrosion or

erosion are produced by use of a standard 0°transducer. By using a CCD camera and the video-

tracking system, real time graphic images are

generated by scanning a hand held probe.

A Light Emitting Diode (LED) is attached to the

transducer. The camera tracks this LED to obtain

the positional information required by the system.

Each thickness is assigned a separate colour, and agraphic contoured image is produced showing a

topographical map of the internal surface condition.



3

Corrosion Mapping

CCD Camera

Microplus Imaging System

Light Emitting Diode



4

A selection of software routines such as 3-Denhancements, material percentage losses, cross-

sectional images, is included in the µmapsoftware package



5

Corrosion Mapping

Composite Image

By Joining Scan

Files



6

Corrosion Mapping

Key Features

As no mechanical scanners are necessary, thistechnique permits the ultrasonicimaging of complex geometry’s such as

Tees, Valves and Bends.

Colour composite images may be generatedby joining individual scan areas, to show theoverall condition of plant.

Coverage is guaranteed as non-inspected

areas are highlighted On-Line analysis

Automatic Report generation



7

Corrosion Mapping

Image showing

Isolated Pits



8

Time of Flight Diffraction

TOFD



9

Developed to accurately size and monitor the

through wall height of in service flaws in the nuclear

industry.

Equally effective for the detection of flaws in welding,

irrespective of type or orientation.

Does not rely on the reflectivity of the flaw

Uses the diffracted sound initiated from the flaw tips



10

2 Probes opposite

each other. 1 transmittingand 1 receiving the signals



11

Tx Rx

Lateral wave

Signal returned from backwall

Energy is transmitted in to the Material in short burstsThe energy spreads out into an angular beam



12

Planar flaw

upper tip

lower tip

Tx Rx

Lateral wave

Backwall

Energy is diffracted from both upper and lower flaw tips



13

upper tip

lower tip

Tx Rx

Upper flaw

tip

Lower flawtip



14

Benefits of TOFD Real Rime Inspection Results

Superior inspection reliability

Reduced inspection time

Accurate sizing

Reliable propagation monitoring

No necessity to shut down plant asinspection can be deployed "on-line"

Cost effective

Hard Copy Evidence

Repeatable

Easy Storage of data



15

Corrosion

Top Surface

Inner Surface

TOFD forWeld root Corrosion



16



17



18



19

Phased ArrayPhased Array – –

A Basic IntroductionA Basic Introduction



20

Why Phased Array?

• High speed electronic scanning without moving parts

• Improved inspection capabilities through softwarecontrol of beam characteristics

• Inspection with multiple angles with single,

electronically controlled probe

• Greater flexibility for inspection of complex

geometries

– Optimized focusing

– Optimized beam angle



21

Phased-Array

ProbeBasically, a phased-array is a long conventional probe

cut into many elements.



22

Electronic (Linear)Scanning



23



24

Beam Steering

• Is the capability to

modify the refracted

angle of the beamgenerated by the array

probe.• Allows for multiple

angle inspections,using a single probe

• Applies asymmetrical(e.g. linear) focal laws



25



26

Combined Beam

Processing

Linear combined with steering and focusing



27

Applications ApplicationsInIn--service weld inspection including Stressservice weld inspection including Stress

Corrosion CrackingCorrosion Cracking

As welded defect detection As welded defect detection

Complex GeometriesComplex Geometries – – Nozzles, FlangesNozzles, Flanges, Shafts, Shafts

CC--Scan mappingScan mapping



28



29

CHIME



30

CHIME

Creeping Head-

Wave Inspection

Method

CHIME



31

CHIME

An ultrasonic technique for the efficient, rapid and

complete inspection of pipe or plate called CHIME for

the examination of under-clamp or under-support

corrosion:

Large area, single pass corrosion,

pitting and crack detection

Probe separation up to 1m or more 100% coverage of material between the

probes

Suitable for steel pipes and plate

Sensitive to both internal and external

surfaces

Applications of CHIME



32

Applications of CHIME

• Pipe Supports, saddles or

sleepers

• Clamps

• Vessels/Tanks

• Pipe screening for internalcorrosion

• Pipes with limited access

The CHIME technique



33

The CHIME technique

Time

Head WavesBulk Waves

CHIME on Isolated Pits



34

CHIME on Isolated Pits

P1 P2 P3

e Probe movement Tim

Pit depth is 25% to 100% of WT

25% 100% 55%

CHIME for Internal Pipe Inspection



35

CHIME for Internal Pipe Inspection

CHIME for Pipe Supports



36

CHIME for Pipe Supports

Example of data collection around a pipe support

Note: Inspection can be carried out using either set up a) or b) only

CHIME on 6” Pipe Section



37

p

Wavemaker



38

Wavemaker

Pipe Screening System



39

Waves are sent along the pipe• 10’s of meters of

pipe areexamined fromone location

• Difficult toinspect areas,such as roadways

can be screenedfor defects



40

Capabilities

• Can be performed at elevated temperatureswithout taking the pipe out of service

• 100% of the pipe is inspected (within thediagnostic length of a test)

• Pulse echo type operation provides informationon feature position and approximate size

• Sophisticated analysis aids interpretation of results



41

Target Applications

• Rapid, full coverage screening of pipes

• Especially cost effective in difficult to access

locations – Sleeved road crossings

– Corrosion under insulation

– Wall penetrations – Pipe racks

– Rope access

• Can detect cracks and general metal loss (greaterthan 5% of the cross-sectional area)



42

Limitations

• Highly attenuous bitumas based coatings

and denso wraps.

• Internal concrete lining on pipes

• Pipe with a high level of general corrosion

will reduce the effective scanning lengths.

• Heavy clay soils.

• Short, less than 5mtr, length of piping.



43

Pre-inspection Set-up

• A ring of

transducers isplaced around thepipe

• No couplant isrequired

• Usually no surface

preparationrequired



44

Small Diameter Pipes

• Tested using solidrings

• For pipes 1 - 8inches diameter

• Can be mounted inless than a minute

• 3 inches clearance

needed aroundpipe8” Ring R2F8



45

Large Diameter Pipes• Tested using inflatable

ring• For pipes 6 inches orgreater

• Employ conventionalfoot pump to inflate

• 2 inches clearance

needed around mostof pipe

12” Ring R2B12



46

How It Works

• Guided wavesare sent ineach direction

• Reflectionsare analysed



47

Position of Ring

Decay CurvesCorrosion is indicated

by large red component

Iconic representation

of identified features

ForwardBackward

Series of Welds

Example #1



48

Pipes passing through earth wall



49

Corrosion at entrance to sleevedroad crossing

-30.0 -20.0 -10.0 0.0 10.00.0

0.2

0.4

0.6

0.8

1.0

Distance (m)

A m p ( m V )

+F1 +F2 +F3+F4-F1-F2-F3-F4

Corrosion

Example #2



50

Example #2

Pipes passing through concrete wall

8 inch pipeunder test

10 inch pipeunder test



51

Result from (corroded) 10 inch pipe

-20.0 -10.0 0.0 10.0 20.00.0

0.5

1.0

1.5

2.0

Distance (m)

A m p ( m V )

-F

Typical Ranges



52

(in each direction, using standard transducers)

• Ideal conditions 80m + (best recorded 220m)

• Typical 30 year old pipe with little internal or externalcorrosion 40m

• Typical 30 year old pipe with some general corrosion20m

• Typical pipe wrapped in factory applied foam 15m

• Heavily corroded pipe or pipe that is bitumenwrapped 5m

• Six welds

• The first flange or the second bend or branch

Note: these ranges can be doubled by using newly available low frequency

transducers although a reduction in sensitivity is also present



53

How to Most Effectively Use the System

• Best used as a screening tool that is part of a

more comprehensive testing strategy – Good at quickly determining which out of a series of

road crossings is most heavily corroded

– Good at quickly locating areas of probable concern

– Can not determine exact sizes (only a roughclassification can be given)



54

INCOTESTINsulated COmponent TEST

INCOTEST I t d ti



55

INCOTEST - Introduction• INCOTEST (INnsulated

COmponent TEST)

• Pulsed Eddy Current - ThicknessMeasurement Through insulation

• Average Thickness over aFootprint

• On-Stream No InsulationRemoval

• Detects Both Internal and

External Wall Loss

INCOTEST



56

Pulsed Eddy Currents Theory

Probe Housing

Receiving Coil

Transmitting Coil

INCOTEST



57

Theory summary• Pulsed Magnetic Field

• Eddy Currents are induced

• Measurement of Eddy Current Voltage

• Detect start / finish of eddy currents in material

• Eddy current Duration / Thickness relationship

INCOTEST



58

Area of Measurement

Volumetric reading over

a given area (footprint)

INCOTEST



59

Area of Measurement

Reading taken overan area of 100% volume of material

INCOTEST



60

Reading taken over corroded area.

Reading will be the remaining volume of material as compared to the reference reading

Area of Measurement

INCOTEST Restrictions



61

INCOTEST - Restrictions• Only suitable for low alloy steels.

• Does not detect isolated pits. Measure the average wall

thickness over a footprint.

• Repeatability typically +/- 2%.

• Limited to wall thickness up to 65mm.

• Limited to insulated pipe diameters over 50mm.

• Cannot differentiate OD from ID loss.



62

• Can work up to 5hrs

on one battery pack.

• Probes can be up to200mtr away from

base unit.



63

• Measures throughany non-magnetic

material, e.g.insulation, concrete,

fire retarder,refractory cement,water, timber and air



64

• Provides acomputed thickness

reading within

seconds.

INCOTEST - Display



65

p y

Contact Measurements



66


• Detects and measures

average wall thicknessthrough non-magnetic

coatings such as paintor concrete



68

• Measures averageremaining wall

thickness onexternally corroded

surfaces




INCOTEST - Summary



70

• No requirement to remove insulation

• Fast

• Gives average wall thickness over a footprint (does notdetect isolated pitting)

• Detects both internal and external corrosion / erosion• Suitable for contact and non-contact applications

• Accurate

• Cost effective



71

Portable Digital Radiography

Applications / Features / Benefits



72

>Refineries for wall thickness measurement and corrosion

>Remote area pipelines

>On board of offshore platforms, submarines, airplanes,

>Railways trucks

>Museum and archeological

Testing on remote and difficult to reach locations

– Computed Radiography employs Imaging Phosphor



73

p g p y p y g g p

Storage Technology, which when irradiated, storesa latent radiographic image for an unspecified

period of time

– Much the same fashion as classical X-ray film



74

Raw ImageRaw ImageContrast enhancementContrast enhancement

by window/levelby window/levelSharpeningSharpeningZoom inZoom inEmboss in ROIEmboss in ROIZoom ROIZoom ROI



75

KernelsStandard

Smooth

Sharp

Emboss



76

Wall Thickness measurement software :



77

Wall Thickness measurement software :

Summary



78

Computed Radiography> Portable CR system

> Have digital images available on the spot> Transports easily between sites and into remote areas

> Dynamic range much higher than film or paper

> no retakes by bad exposure, different thickness in one shot…

> Phosphor plates are reusable

> no film or paper needed : consumable cost saving

> No chemicals, no darkroom

> cheaper infrastructure



79

Tank Floor Inspection

Mk 2 Floorscanner

Tank Floor Inspection



80

pFloorscanners - How does it work?

Magnetic Floorscanners operate on the principle that localised metal loss due to

corrosion pitting in magnetised floor plates produces an anomaly in the fields

above the plate. Magnetisation is achieved by scanning a powerful C-Magnet overthe floor plate. The flux leakage anomalies are detected by an array of sensorsbetween the poles of the magnet

Conveyor Belt



81

Laser Profile Systems



82

Example of raw data

16.5

17

17.5

18

18.5

19

19.5

20

20.5

0 50 100 150 200 250 300 350

3

5

6

7

Top and bottom belt profiles with



83

p p

overall belt thickness



84

Internal LaserProfiling

Crawler



85

Camera / Video SystemsCombination UT

Thickness and videoprobe



86

Internal CaissonVideo System



87

all techniques - in brief

Documents