Seminar for NDT Nivå 3 - Personellndt.sitegen.no/customers/ndt/files/5 Lavfrekvent...

Oslo 24.11.2008Oslo 24.11.2008

Seminar for NDT Seminar for NDT NivNivåå 3 3 -- PersonellPersonell

Low Frequent Eddy Current(Lavfrekvent virvelstrøm)

Arild SolbergArild Solberg Mohan KangMohan Kang

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Oslo 24.11.2008Oslo 24.11.2008 ““NivNivåå 3 Seminar3 Seminar””

Content:Content:

•• Introduction Introduction

• HistoryHistory

•• Technology & Reporting PrinciplesTechnology & Reporting Principles

•• EquipmentEquipment

•• ApplicationsApplications

•• Practical demo of technologyPractical demo of technology



Introduction:Introduction:

Eddy Current Technology (EC)



Eddy Current Technology (EC),

Standard equipment



Eddy Current Technology (EC), Special equipmentHeat Exchanger & Boiler Tube InspectionHeat Exchanger & Boiler Tube Inspection

•• Heat exchangersHeat exchangers•• Coolers Coolers •• BoilersBoilers•• CondensersCondensers•• ReactorsReactors•• Air coolersAir coolers•• Separators Separators •• HeatersHeaters•• AirAir--conditioncondition systemssystems•• etc.etc.



Low Frequent Eddy Current(Lavfrekvent virvelstrøm)

Named:Named:

SLOFECSLOFEC™™

““SSaturation aturation LLow ow FFrequency requency EEddy ddy CCurrenturrent””

The fast inspection screening method for defect detection



History:History:

SLOFECSLOFEC™™““Saturation Low Frequency Eddy CurrentSaturation Low Frequency Eddy Current””



SLOFECSLOFEC™™ TechnologyTechnology

19931993Problem:Problem: Inspection of Nuclear Power Plant Inspection of Nuclear Power Plant -- underground cooling underground cooling

water pipes from inside without removal of inner coating, water pipes from inside without removal of inner coating, detecting external corrosiondetecting external corrosion

Pipe O.D.Pipe O.D. up to 4mup to 4mPipe wall thicknessPipe wall thickness up to 32mmup to 32mmInner coating Inner coating thickness ~ 3 thickness ~ 3 -- 4mm, epoxy type4mm, epoxy typeDetected defectsDetected defects Ext. defects from 30% wall LossExt. defects from 30% wall Loss




19961996Problem:Problem: Inspection of buried and half buried storage vesselsInspection of buried and half buried storage vessels

from inside, detecting external corrosionfrom inside, detecting external corrosion

Storage vessel :Storage vessel : ØØ ~ 4.500mm; ~ 4.500mm; WT 18mmWT 18mm

Detected defects:Detected defects: ext. defects 30%, ext. defects 30%, corrosioncorrosion

Time for inspection: ~ 3 shifts per vesselTime for inspection: ~ 3 shifts per vesselEntrance : Entrance : ØØ 550mm manhole550mm manhole

55% 55% reductionreductionof of inspectioninspection

costscosts




19971997 World Wide evaluation of Petroleum Association of Japan World Wide evaluation of Petroleum Association of Japan Evaluation:Evaluation: Tank floor inspection methods / systemsTank floor inspection methods / systems

Criteria: Criteria: sensitive , economical, handlingsensitive , economical, handlingSuccess: Success: SLOFECSLOFEC™™ evaluated for inspection evaluated for inspection

regulation by laboratory and field testsregulation by laboratory and field tests

TEST TEST RESULTS:RESULTS:Plates wt 9mm, 12mm, 21mm Plates wt 9mm, 12mm, 21mm Coating 1 Coating 1 -- 3mm3mm

Smallest detected underside defects:Smallest detected underside defects:

wt 9mm wt 9mm -- ØØ 2mm, depth 20%2mm, depth 20%






2000 SHELL - Expro Brent Field Project: Inspection of Oil Rundown Lines in concrete legs

Evaluation of SLOFEC™ Pipe Scan sensitivity - result : qualified

Success: Inspection of pipes up to OD 30”; up to wt 26mmcoatings/wrap. up to 5mm




Main targets for SLOFECSLOFEC™™ inspections are:

- Detection & identifying of localised corrosion areas (sensitive to localised defects, pitting, MIC, etc.)

- Fast scanning to receive a quick condition overview- Scanning through coatings to avoid removing it

1.000

2.000

2.500

00°90°180°270°360°

Scan

Len

gth

Pipe Circumference



Technology & ServicesTechnology & Services

Corrosion Detection & Screening Corrosion Detection & Screening

Corrosion detection Corrosion detection & screening& screening

at at Tanks,Tanks,

Vessels, Separators Vessels, Separators

Pipes, Pipelines, etc.Pipes, Pipelines, etc.

withwith

SLOFECSLOFEC™™TechnologyTechnology



Technology & Reporting Principles:Technology & Reporting Principles:





EDDY CURRENT SENSORS

MAGNET

TEST PIECEMAGNETIC

FIELD LINES DEFECT COMPRESSED MAGNETIC FIELD LINES




Response of the Differential Eddy Current Coil System Response of the Differential Eddy Current Coil System (with SLOFEC(with SLOFEC™™) to detect Local Defects) to detect Local Defects

Scan direction

S igna

lAmp

litude

Signal Response of the Differential Channel




SLOFECSLOFEC™™ inspection makes use of Eddy Current Differential inspection makes use of Eddy Current Differential Channel for detection of localized material changes (Defects)Channel for detection of localized material changes (Defects)

Signal response to a local and gradual defectSignal response to a local and gradual defect




SLOFECSLOFEC™™ Comparison Method Comparison Method -- CalibrationCalibrationCalibration with artificial Calibration with artificial reference defectsreference defects

Evaluation of indications in Evaluation of indications in comparison to calibrationcomparison to calibration




SLOFECSLOFEC™™ Sensitivity TestSensitivity Test




SLOFECSLOFEC™™ Accuracy TestAccuracy Test

20%

20%

40%

60%

80%

100%

mechanic measured defect depth[% of the nominal wall thickness]

Def

ect D

epth

eva

luat

ed b

y th

e SL

OFE

C S

yste

m[%

of t

he n

omin

al w

all t

hick

ness

]

40% 60% 80% 100%

P9

P11a&b

P6

P3

P8P5

P2

P16

P7P4 P21

P1

P10a

P12a&b

Ground Truth Diagram Ground Truth Diagram for Ground Truth Diagram for comparison SLOFECcomparison SLOFEC™™evaluated to measured evaluated to measured defect depthdefect depth

performed with SHELL Global performed with SHELL Global Solutions (Amsterdam)Solutions (Amsterdam)

example:example:plate thickness plate thickness 18mm material ST35.818mm material ST35.8




SLOFECSLOFEC™™ Confirmation of Detected DefectsConfirmation of Detected Defects

Tank floor: Tank floor: Chemical PlantChemical PlantPlate thickness: Plate thickness: 12mm12mmCoating : Coating : Rubber, 10mm thickRubber, 10mm thickDefects :Defects : Corrosion pits fromCorrosion pits from underside, underside,

2020--30% loss, additional through 30% loss, additional through holes foundholes found

Confirmed :Confirmed : by UTby UT




SLOFECSLOFEC™™ Distinction Distinction -- Underside / Topside DefectsUnderside / Topside Defects

Artificial defect (dia. 10mm) at Artificial defect (dia. 10mm) at the underside side depth 40%the underside side depth 40%

Topside corrosion Topside corrosion Corrosion Corrosion pitpit diameter 15mm, depth 20%diameter 15mm, depth 20%

SignalSignaldisplay of display of UNDERSIDE UNDERSIDE DEFECTSDEFECTS

VERTICAL SIGNAL VERTICAL SIGNAL ORIENTATIONORIENTATION

SignalSignaldisplay of display of TOPSIDE TOPSIDE DEFECTSDEFECTS

HORIZONTAL SIGNAL HORIZONTAL SIGNAL ORIENTATIONORIENTATION




SLOFECSLOFEC™™ Field inspection results compared to UT resultsField inspection results compared to UT results

Project: Project: Result comparison UT mapping , Result comparison UT mapping , -- SLOFECSLOFEC™™ results results -- UT reUT re--inspection results of SLOFECinspection results of SLOFEC™™ detected defects detected defects

Object:Object: Offshore knock out drum (wt 25mm)Offshore knock out drum (wt 25mm)

SLOFEC Comparison

05

1015202530

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18Grid No

mm

AEA minSLOFEC

SLOFEC Comparison

05

1015202530

1 3 5 7 9 11 13 15 17

Grid No

mm

AEA minSLOFECSLOFEC UT




Relative Sensitivity Curve, in comparison to MFLRelative Sensitivity Curve, in comparison to MFL

Wall thickness [mm]

MFLSLOFEC

2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36Rel

ativ

e D

etec

tion

Sens

itivi

tyR

elat

ive

Det

ectio

n Se

nsiti

vity

2d

WT

d

d / WT = detect ability [%]




SCANNING SCANNING

SOFTWARE & REPORTINGSOFTWARE & REPORTING




Scan & Scan Imaging SoftwareScan & Scan Imaging Software

or

Scan Software Indication Scan Software Indication --display while scanningdisplay while scanning

Scan Imaging Software Scan Imaging Software for coloured condition imagingfor coloured condition imaging




Colour ImagingColour Imaging -- Defect ClassificationDefect Classification

COLOUR PALETTE – DEFECT CLASSIFICATION:

Display of indication amplitude analysis, representing wall loss in comparison to reference

< 20% 20 - 30% 30-40% 40-50% >50%




Colour ImagingColour Imaging -- Tank Floor InspectionTank Floor Inspection

Tank Floor Scan Defect Mapping Tank Floor Scan Defect Mapping ColourColour details for defect imagingdetails for defect imaging




Colour Colour Imaging Imaging -- Tank Floor InspectionTank Floor Inspection

Tank floorTank floor--Single Plate Scan ReportSingle Plate Scan Report

Colour details for defect imagingColour details for defect imaging

Including details of Including details of UT UT -- verified indicationsverified indications




Colour ImagingColour Imaging -- Pipe InspectionPipe Inspection

20-3

0%

30-4

0%

40-6

0%

< 20

%

> 60

%

Signal of the reference internal defect (50%depth) inthe signal Y-component / phase analyse window

Sec

tion

12.

230m

mS

ectio

n 2

1.90

0mm

Sec

tion

33.

685m

mSe

ctio

n 4

2.72

0mm

14

13

15

16

17

18

19

20

21

22

23

Distance to GTF[meter]

Flange Weld (FW)

Top of steel (TOS)

Section 5450mm

24

25

26

27

28

29

30

31

32

33

34

Client :

Location :

Subject :

OIL COMPANY

Oil Rundown Lines

REFINERY

Section : 4

Date :

K-No. :

. :

July/Agust 2000

105/00

Pipe Identif P-53

SLOFEC - PipeScan ReportTM

Colored defect Colored defect

map from a inspected map from a inspected

pipe sectionpipe section




Colour ImagingColour Imaging -- Pipe InspectionPipe Inspection

Leng

th2.

000m

m

Dia

met

er o

f the

pipe

: 30

”

Signal component Y-axis set forindications of subsurface corrosion

20-3

0%

30-5

0%

50-7

0%

< 20

%

> 70

%

Length Position

Axia

l dire

ctio

n

Scan Direction

Uninspected area

LongitudinalWeld

Support Beam




Colour ImagingColour Imaging -- Defect ProgressionDefect Progression

1.000

2.000

2.500

00°90°180°270°360°

Scan

Len

gthPipe Circumference

1.000

2.000

2.500

00°90°180°270°360°

Scan

Len

gth

Pipe Circumference

Scan Scan -- Inspection 1Inspection 1 Scan Scan -- Inspection 2Inspection 2



Equipment:Equipment:





SLOFECSLOFEC™™ EquipmentEquipment

Pole Shoes,Pole Shoes,SensorsSensorsWheelsWheels

ScannersScanners

Computerized ET SystemComputerized ET System




Tank floor Scanner FS400Tank floor Scanner FS400

SLOFECSLOFEC™™ Floor Scanner Floor Scanner 400mm width400mm width8 EC Sensors8 EC Sensors SLOFECSLOFEC™™ eddyMaxeddyMax

computerized eddy current systemcomputerized eddy current system




FEATURES:FEATURES:

Materials:Materials: fefe-- and and nn--fefe materials materials Plate thickness:Plate thickness: up to 32 mm (up to 32 mm (fefe--materials)materials)Coating types:Coating types: all all electrelectr. non conductive. non conductiveCoating thickness:Coating thickness: up to 10 mm (field experience)up to 10 mm (field experience)Operation:Operation: 2 men2 menCleaning: Cleaning: free of mud / broom cleanedfree of mud / broom cleanedScanScan--coverage:coverage: dead zones dead zones -- edgesedgesDefect detection:Defect detection: in bear metal, in bear metal,

in overlapped plates, in overlapped plates, at annular plates up to 30 mm at annular plates up to 30 mm distance to the shelldistance to the shell

Productivity:Productivity: depending of tank size depending of tank size ~ 400m~ 400m²² -- 600m600m²² /shift/shift

Tank floor Scanner FS400Tank floor Scanner FS400




Tank floor Scanner FS300Tank floor Scanner FS300FEATURES:FEATURES:

Materials:Materials: fefe-- and and nn--fefe materials materials Plate thickness: Plate thickness: up to 15 mm (up to 15 mm (fefe--materials)materials)Coating types: Coating types: all all electrelectr. non conductive. non conductiveCoating thickness: Coating thickness: up to 6 mm (field experience)up to 6 mm (field experience)Operation:Operation: 2 men2 menCleaning: Cleaning: free of mud / broom cleanedfree of mud / broom cleanedScanScan--coverage: coverage: dead zones dead zones -- edgesedgesDefect detection: Defect detection: in bear metal, in bear metal,

in overlapped plates, in overlapped plates, at annular plates 15 mm at annular plates 15 mm

Productivity: Productivity: depending of tank size depending of tank size ~ 300m~ 300m²² -- 500m500m²² /shift/shift




Pipe Scanner PS 200Pipe Scanner PS 200

Type:Type: Electromagnet Electromagnet Input :Input : 110/220V AC110/220V ACWT Range: up to 26mmWT Range: up to 26mmAdapt ions: Adapt ions: 44”” to flat to flat




Pipe Scanner LS 150Pipe Scanner LS 150

Type:Type: Electro MagnetElectro MagnetWT Range: up to 18mmWT Range: up to 18mmAdapt ions: 4Adapt ions: 4”” to flatto flat





Type:Type: Permanent MagnetPermanent MagnetWT Range: up to 12,5mmWT Range: up to 12,5mmAdapt ions: 2Adapt ions: 2”” to flatto flat





Type:Type: Permanent MagnetPermanent MagnetWT Range: up to 9mmWT Range: up to 9mmAdapt ionsAdapt ions: 1: 1”” to flat to flat




Scanner TWC 20Scanner TWC 20

Self driving scanner for i.e. Self driving scanner for i.e. vertical surfaces vertical surfaces




SLOFECSLOFEC™™ Sub seaSub sea ScannerScanner

Target: Inspecting Riser Pipe/Caissons through Coatings & MarineTarget: Inspecting Riser Pipe/Caissons through Coatings & Marine growthgrowth

Test Results e.g.: Test Results e.g.: 1212”” Pipe x WT 20mm , Coating 15mmPipe x WT 20mm , Coating 15mmDetected Internal pits:Detected Internal pits: ØØ 15mm, detected from 20% wall loss15mm, detected from 20% wall loss




Internal pipe inspections, examples Internal pipe inspections, examples

Eddy Current & SLOFEC Internal Eddy Current & SLOFEC Internal Internal Pipe Scanner i.e. 16Internal Pipe Scanner i.e. 16”” pipepipe



Applications:Applications:





““TANKFLOOR INSPECTIONTANKFLOOR INSPECTION””




Inspection of Storage TanksInspection of Storage Tanks

Tank floorsTank floors




Inspection of Storage Tanks Inspection of Storage Tanks -- wallswalls




““PIPE INSPECTIONPIPE INSPECTION””




Pipe Scanning Pipe Scanning -- ExamplesExamples

Target: Screening of pipe bottom Pipe: 24“ Naphtha Line ; WT : 1/2 „Detected defects: 20% wall loss from inside, Ø 4mm,

mainly CO² corrosion 6`clock lineTime of inspection: ~ 15 min. for 9m (180° coverage)





Process pipe workProcess pipe work





Inspection at temperature 80°C

Target: Detection of MIC (Micro Biological Corrosion) in early stage. A tool as early warning of corrosion

Pipe dia.: 16“WT: 13mmDetected defects: 15% wall loss from inside

2-3mm in diameterTime of inspection : 20min. for 6m (360° coverage)





Target: Target: Internal corrosion screening / detection of Internal corrosion screening / detection of galvanised fire water pipesgalvanised fire water pipes

Pipes:Pipes: ~ 2~ 2““ --1010““ ; WT : up to 9mm; WT : up to 9mmDetected Detected defects:defects: 20% 20% -- 30% int. wall loss, from ~ 30% int. wall loss, from ~ ØØ 3mm3mm





Target: Screening of furnace tubes from outside

Pipe: 6“ Furnace Tube; WT : 9mmDetected defects : 20% int. wall loss, from Ø 3mm,

massive corrosion at furnace sideTime of inspection : ~ < 10 min. for 12m (180° coverage)




““PIPE INSPECTIONPIPE INSPECTION””

Example scanning speedExample scanning speed





Project:Project: Inspection of Oil Rundown Lines in concrete legs Inspection of Oil Rundown Lines in concrete legs Evaluation of SLOFECEvaluation of SLOFEC™™ Pipe Scan sensitivity Pipe Scan sensitivity -- result : qualifiedresult : qualified

Success:Success: Inspection of pipes Inspection of pipes up to OD 30up to OD 30””; up to wt 26mm; up to wt 26mmcoatings/wrappings up to 5mmcoatings/wrappings up to 5mm





Pipe work inspected by SLOFEC, Pipe work inspected by SLOFEC, in the shaft of a concrete in the shaft of a concrete platform structureplatform structure




Pipe Inspection Pipe Inspection –– Project reportingProject reporting





Sea water lift Caissons inspection Sea water lift Caissons inspection performed with SLOFEC Technologyperformed with SLOFEC Technology





Example Inspection of CaissonsExample Inspection of Caissons





CupCup--typetype PitsPits

Pit ClustersPit Clusters

Sandblasted internal pipe surface Sandblasted internal pipe surface

with detected MICwith detected MIC





Cut of pipes withCut of pipes withchloride corrosionchloride corrosion

Target: Target: Stainless SteelStainless Steel Pipes (Offshore)Pipes (Offshore)Chloride corrosion detection Chloride corrosion detection and depth determination and depth determination

Pipes:Pipes: 11““ --1010““ ; WT : up to 11mm; WT : up to 11mm

Detected Detected defects:defects: Chloride Corrosion fromChloride Corrosion from

20% 20% -- 30% wall loss30% wall loss




““VESSEL & TANK INSPECTIONVESSEL & TANK INSPECTION””




Vessel Inspection Vessel Inspection -- ExamplesExamples

Vessel: Production Vessel Ø 2.800mm; WT: 13mm; Temp.: 120°CDetected defects : Isolated pits 20% int. wall loss from Ø 4mm,





Vessel :Vessel : Knockout Drum (offshore) Knockout Drum (offshore) ØØ 2.600mm; WT : 252.600mm; WT : 25--28mm28mminternal stainless steel linerinternal stainless steel liner

Detected defects:Detected defects: Internal defects 30% int. wall loss, isolated pits, cor. areasInternal defects 30% int. wall loss, isolated pits, cor. areasTime for inspection:Time for inspection: 3 3 -- 4 shifts for 2 drums4 shifts for 2 drums




SLOFECSLOFEC™™

““CONCLUSIONCONCLUSION””




Conclusion of SLOFECConclusion of SLOFEC™™

-- Fast corrosion screening method for local metal lossFast corrosion screening method for local metal loss

-- Inspection of thick wall components (up to 32 mm)Inspection of thick wall components (up to 32 mm)

-- Inspection through thick coating (up to 10 mm)Inspection through thick coating (up to 10 mm)

-- High defect detection sensitivity High defect detection sensitivity

-- Distinction between topside and bottom defectsDistinction between topside and bottom defects

-- Colored condition mappingColored condition mapping

-- High potential for additional applicationsHigh potential for additional applications

-- Inspection at higher temperatures (experience up to 130Inspection at higher temperatures (experience up to 130°°C)C)

-- Inspection of Fe Inspection of Fe -- & Non Fe & Non Fe –– Materials (CS, Duplex, Stainless)Materials (CS, Duplex, Stainless)




Other applications by use of SLOFECOther applications by use of SLOFEC™™

-- Sub sea inspections (Riser pipes, Caissons, etc.) Sub sea inspections (Riser pipes, Caissons, etc.)

-- Spherical tank inspection Spherical tank inspection

-- Duplex Material InspectionDuplex Material Inspection

-- Internal pipe inspectionsInternal pipe inspections




SLOFECSLOFEC™™ PipeScanningPipeScanning -- Examples Examples

DUPLEX / SUPER DUPLEXDUPLEX / SUPER DUPLEX

Ø2mmD 3mm

Ø3mmD 3mm

Ø2mmD 3mm

4 x Ø 3mmTWH

4 x Ø 5mmTWH

Ø8mmD 12mm

Ø5mmD 12mmØ

3mmD 12mm

Ø8mmD 9mm

Sensitivity Test at Duplex & Sensitivity Test at Duplex & Super Duplex PipesSuper Duplex Pipes

1010”” x WT 4.19mmx WT 4.19mmSmallest internal defect detected:Smallest internal defect detected:ØØ 2mm , Depth 24%2mm , Depth 24%



For further information, kindly contact:For further information, kindly contact:

KTN AS KTN AS Fjøsangervn. 50P.Boks 6078 Postterminalen5892 BergenNORWAY

Phone: + 47 55205300 E-mail: [email protected]

www.ktn.no

Technology & ServicesTechnology & Services



Seminar for NDT Nivå 3 - Personellndt.sitegen.no/customers/ndt/files/5 Lavfrekvent...

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