Content

KINT Acceptance Criteria for Phased Array UT (ACPA) project

Lack of reliable information on PAUT performance

Solution

Samples

Procedure

Results & Conclusions

2

The KINT ACPA project Goal:

Develop Good WorkmanShip acceptance criteria for

PAUT, leading to same quality level as RT, to be

published as EN/ISO norm

ScopeThin walled low alloy steel between 3.2-8.0 mm

Original plan: Four project “phases”

Theoretical – practical

Past experience – testing/validating

Phase A & B provide proposed AC and supporting

information

Phase C & D validate rejection rate (D) and

Probablity of Failure for standard case (C)

3

Legenda: Experience

Checking

Theoretical part

Practical part

• Part D

• Field verification

• Part C

• Fracture Mech validation

• Part B

• Evaluation projects

• Part A

• Inventory literature

Part E

Concept Std.

Evaluation

The challenge Outcome Phase B

Lack of quality data on PAUT performance for

thin walled weld inspection

No POD curves available

Some answers available via simulation

Effect diameter on sizing

Effect frequency on detection

Embedded vs surface breaking indications on small

wall thickness

Many validations focused on proving detection

of known indications – no false calls/many missed

defects

4

0

1

2

3

4

5

6

7

8

9

10

No information Unsure on whatinformationavailable

Information ononly samples

withmanufactured

defect

Information onsamples with

bothmanufacturedand natural

defects

Research questions

Research question unresolved in Phase B:

POD curves for PAUT – input for Phase C

Sizing performance?

Is characterisation (type of indication, surface breaking)

possible?

False calls?

Which essential variables influence PAUT performance most

(from statistical point of view)?

Several inspection methods accepted by EN/ISO 20601:2018

do they perform equally well? Or need for differentiation in

acceptance criteria?

5

The Reliability Study Objective

Blind, controlled trial testing current

capabilities per EN/ISO 20601

Compare RT and PAUT indication by

indication

Gather sufficient data to formulate statically

significant answer to outstanding questions

Make trial reproducable

Method

155 pipe spools with 338 (mostly) natural

defects within project scope dimensions

X-ray and PAUT by different companies per

standardized test plan

Use CT instead of macrosectioning for

objective comparison6

The Samples

7

0

10

20

30

40

50

60

0 1 2 3 4 5 6 7 >8

# s

am

ple

s

# Indications per sample

• Provided by trial

participantsLabeled, partly available

• Mostly natural defects (qualification

weld specimen)

Testing

8

Standardized testing plan for RT and PAUT

Standardized set of calibration and reference samples for curved probes

Essential variables varied in PAUT:

Comments

Frequency

of probes

Tested with CIVA simulation – standardised

based on wall thickness

Scanning

technique

Only two scanning techniques from EN/ISO

20601 :

• One off-set positions on either side of weld

(double sided)

• Two off-set positions on same side of weld

(single sided)

Sizing

method

Based on Phase A&B outcome: only use

amplitude/length sizing

Reporting & interpreting

Standard reporting sheet

Record of every reported indication with image

material

Significant effort on comparing data on indication by

indication basis

Project ID Weld ID Material Geometry Diameter Weld length Wall thickness Defect# Locatie mm Lengte Diepte HoogteDefect

indentification

Surface breaking

(1=yes, 0=no)

Detected RT

(1=yes, 0=no)Defect type Defect length mm Defect indentification2 Level 1

A+ 7,5 MHz KINT 07 CS Pipe 33.75 106 3.4 1 0

A+ 7,5 MHz KINT 07 CS Pipe 33.75 106 3.4 2 84.81 1.06 0 0.7 Tungsten 0 0 0

A+ 7,5 MHz KINT 08 CS Pipe 33.75 106 3.4 no defects 0

A+ 7,5 MHz KINT 09 CS Pipe 33.75 106 3.4 1 100.09 1.17 3.8 0.5 Porosity 0 1 Single pore / short ind. 0.5 Gas pore (2011) ACC

A+ 7,5 MHz KINT 09 CS Pipe 33.75 106 3.4 2 1 Single pore / short ind. 0.4 Gas pore (2011) ACC

Object indentification RADIOGRAPIC TESTINGCT

Defects present

0

10

20

30

40

50

60

227 defects in total

Performance - POD

0

0,1

0,2

0,3

0,4

0,5

0,6

0,7

0,8

0,9

1

0 5 10 15 20 25 30 35 40 45

PoD

[-]

Actual defect length [mm]

RT PAUT (Double sided) PAUT (Single sided)

Performance - Sizing

-12

-8

-4

0

4

8

12

0 5 10 15 20 25 30

Rep

ort

ed

len

gth

-a

ctu

al le

ngth

(m

m)

Actual defect length (mm)

Length sizing error PAUT

-12

-8

-4

0

4

8

12

0 5 10 15 20 25 30

Rep

ort

ed

len

gh

t -

actu

al le

ngth

(m

m)

Defect length (mm)

Length sizing error RT

PAUT double sided data set

Performance - CharacterisationRT

0

5

10

15

20

25

30

Clustered

Porosity

Lack of fusion Lack of

penetration

Multiple Porosity Tungsten Undercut wormhole

Clustered indications Elongated indication Geometry Single pore / short ind.

Performance - Characterisation

0

5

10

15

20

25

30

ClusteredPorosity

Crack Excessivepenetration

Lack offusion

Lack ofpenetration

Multiple Porosity Tungsten Undercut wormhole

Other Planar defect Root defect Volumetric defect

PAUT - double sided data set

Performance – False Calls

0

0,1

0,2

0,3

0,4

0,5

0,6

0,7

Missed defect Detected defect FC

Single sided Double sided RT

• Sample sets of both Single Sided skew angles treated independently

• Normalized on # indications present in samples

Performance – False Calls

0

5

10

15

20

25

30

35

40

45

50

Hits False calls

0

10

20

30

40

50

60

70

80

90

PAUT double sided data set – trial effect?

Performance – False CallsPAUT double sided data set – trial effect?

0

2

4

6

8

10

12

14

16

0 2 4 6 8 10

# F

als

e c

all

pe

r sa

mp

le

# actual defect present per sample

Moreover:

• Indication by indication review

shows likely false calls because

of mode conversion

• Simulation shows “ghost”

indication caused by

unexpected sound paths on

small diameter

• Trial effect does seem to play a

role

Conclusions For the development of Phased Array acceptance criteria:

Do not use indication characterisation

(*)Do not differ between surface breaking/embedded

(*)No diffraction signals found – use amplitude-length based method

Proper POD and defect population for Phase C

False calls – more work to be done (but not relevant for Acceptance

Criteria):

Trial effect likely

Some ultrasonic phenomena on small wall thickness/diameter not fully

understood yet

Training of NDT technicians (or technical solution) for mode conversion

Thank you!

Phase B project team – Casper, Rene, Ronald, with special thanks to

Thom, Eric and Casper

Project leads – Leo, Casper and Erik

All NDE companies