Phased Array UT Versus RT Report Truncated

TUBE BUTT WELD SAMPLE 7C-040 2.5”Diameter X .180” Nominal Wall Thickness

RT

Detection

PAUT

Detection

Actual

Height - .094” Height - .067” Height - .130”

.21”

.24”

0

0

7.850”


0

0

.19”

.35” .35”

.51” .28”

Flaw #1 Flaw #2 Flaw #3 OD

ID

OD

ID

ID

OD

7.850” .25”

Flaw #1 Flaw #2 Lack of Fusion Slag Inclusion

Babcock & Wilcox Canada Tube to Tube Butt Weld

Nondestructive Examination


.14”

.24”

0

0

7.850”


0

0

.69”

.51” .41”

.47” .43”

Flaw #1 Flaw #2 Flaw #3

OD

ID

OD

ID

ID

OD

7.850”


RT

Detection

PAUT

Detection

Actual



0

0

6.280”



0

0

.31”

.54” .55” .56”

.55” .71” .71”

Flaw #1 Flaw #2 Flaw #3 OD

ID

OD

ID

ID

OD

6.280”

TUBE BUTT WELD SAMPLE 7C-042 2”Diameter X .260” Nominal Wall Thickness

Actual

RT

Detection

PAUT

Detection

Flaw #1 Flaw #2

Flaw #3

Lack of Fusion Lack of Fusion

ID Undercut



Flaw #2

Lack of Fusion

Height - .067” Height - .028”

0

0

6.280”


Height - .0”

0

0

.75”

1.17” .34” .29”

.39” .55” .04”


OD

ID

OD

ID

ID

OD

6.280” .22” .44”

Height – ( -.202”)

Flaw #1

Flaw #3

TUBE BUTT WELD SAMPLE 7C-043 2”Diameter X .260” Nominal Wall Thickness

Actual

PAUT

Detection

RT

Detection

Incomplete Penetration

Lack of Fusion




.25” .38”

.12”

.40” .25”

.51”

0

0

7.850”


0

0

.44”

.21”


OD

ID

OD

ID

ID

OD

7.850”


RT

Detection

PAUT

Detection

Actual

Flaw #1 Flaw #2

Flaw #3

Lack of Fusion and Small Pore

Lack of Fusion and Small Pore

Excess

Penetration



TUBE BUTT WELD SAMPLE 1-1 2”Diameter X .165” Nominal Wall Thickness

Flaw #1 Flaw #1

Flaw #2

Porosity Cluster Porosity Cluster

Root Concavity

Flaw #3

Root Concavity

Lack of Fusion




.08”

Root Porosity

.08”

0

0

6.090”

Height – (- .029”)

Height - .130”

0

0

.13”

.12

”

.13”

.20”

Flaw #1 Flaw #2

Flaw #3 OD

ID

OD

ID

ID

OD

6.090” .13”

Actual

PAUT

Detection

RT

Detection

TUBE BUTT WELD SAMPLE 1-3 1.75”Diameter X .200” Nominal Wall Thickness

No Flaw Discovered During

Cross Sectioning

Flaw #1 Flaw #2

Flaw #3

Porosity Cluster

Porosity in Root



Height - .075”

.35”

.44”

.35”

0

0

5.510”

Height - .090”

Height – (-.133”)

Height - .0”

0

0

.59

”

.35”

Flaw #1 Flaw #2

OD

ID

OD

ID

ID

OD

5.510” .38”

Flaw #1

RT

Detection


Actual

PAUT

Detection

Flaw #1 Flaw #2

Porosity Cluster

Excess Penetration



.56”

Height - .083”

.43”

Flaw #1

.47”

0

0

7.850”

Height - .142”

Height - .142”

Height - .146”

0

0

.50”

.65” .50”

Flaw #1 Flaw #2

OD

ID

OD

ID

ID

OD

7.850”

RT

Detection

PAUT

Detection

Actual


Flaw #1 Flaw #1

Flaw #2

Incomplete Penetration Incomplete Penetration

Porosity Cluster



.22” .10” .63”

Height – Cap Por - .075”

Height - .067”

.47”

Flaw #1

.59”

0

0

7.850”

Height - .168”

Height – LOF - .097”

Height - .106”

0

0

.56” .55”

Flaw #1 Flaw #2

OD

ID

OD

ID

ID

OD

7.850”

Flaw #3

Actual

PAUT

Detection

RT

Detection

Flaw #1

Flaw #3

Flaw #2

No Flaw Discovered During Cross

Sectioning

TUBE BUTT WELD SAMPLE 2-2 2”Diameter X .165” Nominal Wall Thickness

Lack of Fusion and Small Pores Slag Inclusion and Small Pore



Overview of Examination Results

.16” Root Porosity Height – (-.021”)

.07”

Undercut Height - .009”

Height - .020”

Flaw #1 Flaw #1

.25”

.85”

.39”

0

0

5.970”

Height - .037” Height – .032”


0

0

.59

”

.28”

Flaw #2 OD

ID

OD

ID

ID

OD

5.970” .19”

Flaw #3

.12”

.08”

Actual

PAUT

Detection

RT

Detection

Flaw #1 Flaw #2

Flaw #3a Flaw #3b

Root Concavity ID Undercut

Root Porosity ID Undercut



The results of the radiographic, phased array ultrasonic and destructive examination results

have been graphically presented. Figures #4 through #6 present the detection and height sizing

results with calculated maximum and average height sizing error provided by the phased array

ultrasonic examination. The radiographic examination method is incapable of providing flaw height

data, however, the flaw detection has been shown. Figures #7 through #9 provide the flaw length

sizing capabilities for both the RT and PAUT techniques and Figure #10 provides the flaw

positioning capability of the PAUT technique with respect to the nearest surface of the tube (ID or

OD).

The following graphs have been divided into three flaw groups, planar flaws, volumetric

flaws and geometric flaws. These groupings were established based on flaw service severity,

variations in sizing methodologies with the PAUT technique and obvious differences in

detectability between the PAUT and radiographic methods. For the purpose of this investigation

flaws determined to be lack of fusion, incomplete penetration, or cracking have been deemed planar

flaws. Flaws determined to be slag inclusions or porosity have been deemed volumetric flaws and

flaws determined to be excess penetration, undercut or concave root have been deemed to be

geometric flaws.

Detection and Height Sizing Capability

Planar Flaws

Figure #4

Planar Flaw Detection and Height Sizing

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

0.18

0.2

7C

-04

0 F

law

# 1

7C

-04

0 F

law

# 3

7C

-04

1 F

law

# 1

7C

-04

1 F

law

# 2

7C

-04

2 F

law

# 1

7C

-04

2 F

law

# 2

7C

-04

2 F

law

# 3

7C

-04

3 F

law

# 1

7C

-04

3 F

law

# 2

7C

-04

4 F

law

# 2

1-7

Fla

w #

1

1-8

Fla

w #

1

1-8

Fla

w #

3

Sample #/Flaw #

Fla

w H

eig

ht

(in

ch

es)

Actual

PAUT

RT

* Maximum PAUT Height Sizing Error - .113"

* Average PAUT Height Sizing Error - .039"

* RT height sizing - not applicable - red columns indicate

detection only

Observations



1. Six of the twelve planar flaws found during destructive examination were not detected during radiographic

examination. Of these, all except 7C-043 Flaw #1 which was misinterpreted as a volumetric flaw by PAUT,

were rejected by the PAUT examination. One planar flaw found by radiography was not confirmed by

destructive evaluation. All planar flaws confirmed by destructive evaluation were detected by the phased array

ultrasonic examination.

2. On average the PAUT height sizing capability (.039”) was best when the subject flaw was planar in nature

versus volumetric or geometric. The maximum height sizing error (.113”) occurred when sizing Sample 7C-

043 Flaw #1 which was also misinterpreted as a volumetric type flaw.

Volumetric Flaws

Figure #5

Volumetric Flaw Detection and Height Sizing

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

0.18

7C

-04

0 F

law

# 2

7C

-04

4 F

law

# 1

1-1

Fla

w #

1

1-1

Fla

w #

2

1-1

Fla

w #

3

1-3

Fla

w #

2

1-7

Fla

w #

2

1-8

Fla

w #

1

1-8

Fla

w #

2

2-2

Fla

w #

3a

Sample #/Flaw #

Fla

w H

eig

ht

(in

ch

es)

Actual

PAUT

RT



* RT Height Sizing - not applicable - red columns indicate

etection only

Observations

1. Three of the nine volumetric flaws found during destructive evaluation were not detected during phased array

ultrasonic examination. Of these three flaws, Sample 1-8 Flaw 1 was the only RT rejectable flaw. RT and

PAUT detected a volumetric flaw (pore) in Sample 1-1 that was not observed during destructive evaluation.

All volumetric flaws confirmed by destructive evaluation were detected by the radiographic examination.

2. Significant PAUT flaw sizing error was noted on several volumetric flaws (Max. .110”, Avg. .049”). In all

instances volumetric flaws were undersized for height by the PAUT technique.

Geometric Flaws



Figure #6

Geometric Flaw Detection and Height Sizing

-0.25

-0.2

-0.15

-0.1

-0.05

0

0.05

0.1

7C

-04

1 F

law

# 3

7C

-04

3 F

law

# 3

7C

-04

4 F

law

# 3

1-3

Fla

w #

1

2-2

Fla

w #

1

2-2

Fla

w #

2

2-2

Fla

w #

3b

Sample #/Flaw #

Fla

w H

eig

ht

(in

ch

es)

Actual

PAUT

RT



* RT height sizing - not applicable - red columns indication

detection only

Observations

1. The minor root concavity in Sample 7C-044 Flaw #3 was not detectable by the PAUT technique. This flaw

was detected and accepted by RT. The minor undercut flaw in Sample 2-2 Flaw #3b was not detected by RT.

This flaw was recorded and accepted by PAUT.

2. The excess penetration flaws in Sample 7C-043 Flaw #3 and Sample 1-3 Flaw #1 were marginally detected by

the PAUT technique, however, this technique provides no insight into the severity of the excess penetration

condition.

Length Sizing Capability

Planar Flaws

Figure #7

Planar Flaw Length Sizing

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

7C

-04

0 F

law

# 1

7C

-04

0 F

law

# 3

7C

-04

1 F

law

# 1

7C

-04

1 F

law

# 2

7C

-04

2 F

law

# 1

7C

-04

2 F

law

# 2

7C

-04

2 F

law

# 3

7C

-04

3 F

law

# 1

7C

-04

3 F

law

# 2

7C

-04

4 F

law

# 2

1-7

Fla

w #

1

1-8

Fla

w #

1

1-8

Fla

w #

3

Sample #/Flaw #

Fla

w L

en

gth

(in

ch

es)

Actual

PAUT

RT

* Maximum PAUT Length Sizing Error - .26"

* Average PAUT Length Sizing Error - .120"

* Maximum RT Length Sizing Error - .56"

* Average RT Length Sizing Error - .294"

Observations



1. Planar flaws are oversized for length by PAUT in 67% of the sample flaws. Planar flaws are not detected, or

are undersized for length, by RT in 92% of the sample flaws.

Volumetric Flaws

Figure #8

Volumetric Flaw Length Sizing

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

7C

-04

0 F

law

# 2

7C

-04

4 F

law

# 1

1-1

Fla

w #

1

1-1

Fla

w #

2

1-1

Fla

w #

3

1-3

Fla

w #

2

1-7

Fla

w #

2

1-8

Fla

w #

1

1-8

Fla

w #

2

2-2

Fla

w #

3a

Sample #/Flaw #

Fla

w L

en

gth

(in

ch

es)

Actual

PAUT

RT

* Maximum PAUT Length Sizing Error - .160"




Observations

1. On average volumetric flaws are more accurately sized for length, by both PAUT and RT, than planar or

geometric flaws.

Geometric Flaws

Figure #9

Geometric Flaw Length Sizing

0

0.2

0.4

0.6

0.8

1

1.2

1.4

7C

-04

1 F

law

# 3

7C

-04

3 F

law

# 3

7C

-04

4 F

law

# 3

1-3

Fla

w #

1

2-2

Fla

w #

1

2-2

Fla

w #

2

2-2

Fla

w #

3b

Sample #/Flaw #

Fla

w L

en

gth

(in

ch

es)

Actual

PAUT

RT

* Maximum PAUT Length Sizing Error - 1.130"






Observations

1. Geometric flaw length sizing is less accurate with PAUT than any other flaw type. On average RT length sizes

geometric flaws more accurately than planar flaws and less accurately than volumetric flaws.

PAUT Subsurface Flaw Positioning Capability

Figure # 10

PAUT Subsurface Flaw Position Error Versus Actual

-0.14

-0.12

-0.1

-0.08

-0.06

-0.04

-0.02

0

0.02

0.04

0.06

0.08

7C

-040 F

law

# 2

7C

-041 F

law

# 2

7C

-042 F

law

# 3

7C

-043 F

law

# 1

7C

-043 F

law

# 2

7C

-044 F

law

# 1

1-1

Fla

w #

2

1-3

Fla

w #

2

1-7

Fla

w #

2

1-8

Fla

w #

1

1-8

Fla

w #

2

Sample # / Flaw #

PA

UT

Err

or

(in

ch

es

)

0 Error Based on Actual Position

PAUT Positional Error from Nearest Surface

- Away From Nearest

Surface

+ Towards Nearest

Surface* Maximum PAUT Flaw Position Error - .114"

* Average PAUT Flaw Position Error - .046"

Observations

1. The general trend reveals the PAUT examination to place the flaw on average .046” further away from the

nearest surface (OD/ID) than was found during the destructive examination.

2. The above graph includes both planar and volumetric flaws that were either detected by PAUT and recorded to

be subsurface, as well as, those that were found to be subsurface during destructive evaluation. Geometric

flaws are inherently associated with surface conditions, therefore, have not been included.



Summary of Critical Examination Characteristics

Table #2

Critical Flaw Evaluation

Characteristic

Phased Array Ultrasonic

Examination

Radiographic Examination

Flaw Detection

1) Planar Flaws

2) Volumetric Flaws

3) Geometric Flaws

1) All planar flaws detected

2) 67% of volumetric flaws

detected

3) 86% of geometric flaws detected

1) 50% of planar flaws detected

2) All volumetric flaws detected

3) 86% of geometric flaws detected

Flaw Height Sizing

1) Planar Flaws

2) Volumetric Flaws

3) Geometric Flaws

1) Average error - .039”

Maximum error - .113”





No Information Available

Flaw Length Sizing

1) Planar Flaws

2) Volumetric Flaws

3) Geometric Flaws






Maximum error – 1.130”





3) Average error – .196”


Flaw Position Location Within the

Weld Cross Section

Average error - .046”


No Information Available

General Observations from Investigation



Figure #11 Planar Surface Flaws

Class 1 & 2 Ferritic Piping Welds - Surface Flaws

Aspect Ratio 0.0

ASME Section XI Table IWB-3514.1

0.012

0.014

0.015

0.016

0.018

0.019

0.021

0.000

0.005

0.010

0.015

0.020

0.025

0.1

5

0.1

6

0.1

7

0.1

8

0.1

9

0.2

0.2

1

0.2

2

0.2

3

0.2

4

0.2

5

0.2

6

0.2

7

0.2

8

0.2

9

Material Thickness (Inches)

Ma

x. F

law

He

igh

t 'a

' (I

nc

he

s)

Max. Flaw Height

Note: Aspect Ratio 0.0 assumes that the length of the flaw is infinite

Figure #12 Planar Surface Flaws

Class 1 & 2 Ferritic Piping Welds - Surface Flaws

Aspect Ratio 0.20 thru 0.50


0.015

0.017

0.019

0.021

0.023

0.025

0.027

0.000

0.005

0.010

0.015

0.020

0.025

0.030

0.1

5

0.1

6

0.1

7

0.1

8

0.1

9

0.2

0.2

1

0.2

2

0.2

3

0.2

4

0.2

5

0.2

6

0.2

7

0.2

8

0.2

9


Ma

x. F

law

He

igh

t 'a

' (I

nc

he

s)

Max. Flaw Height

Note: Aspect Ratio is calculated from the flaw’s length (l) and height (a)

a/l = AR, therefore, the flaw’s length (l) is l = a/AR

Figure #13 Planar Subsurface Flaws



Class 1 & 2 Ferritic Piping Welds - Subsurface Flaws

Aspect Ratio 0.00


0.030

0.034

0.037

0.041

0.045

0.048

0.052

0.000

0.010

0.020

0.030

0.040

0.050

0.0600

.15

0.1

6

0.1

7

0.1

8

0.1

9

0.2

0.2

1

0.2

2

0.2

3

0.2

4

0.2

5

0.2

6

0.2

7

0.2

8

0.2

9


Ma

x. F

law

He

igh

t '2

a' (I

nc

he

s)

Max. Flaw Height

Note: Aspect Ratio 0.0 assumes that the length of the flaw is infinite

Figure #14 Planar Subsurface Flaws


Aspect Ratio 0.20 thru 0.50


0.037

0.041

0.046

0.050

0.055

0.060

0.064

0.000

0.010

0.020

0.030

0.040

0.050

0.060

0.070

0.1

5

0.1

6

0.1

7

0.1

8

0.1

9

0.2

0.2

1

0.2

2

0.2

3

0.2

4

0.2

5

0.2

6

0.2

7

0.2

8

0.2

9


Ma

x. F

law

He

igh

t '2

a' (I

nc

he

s)

Max. Flaw Height

Note: Aspect Ratio is calculated from the flaw’s length (l) and half the flaw’s height (2a/2)

a/l = AR, therefore, the flaw’s length (l) is l = a/AR

In order to classify a flaw as a wholly subsurface flaw and apply the examples of a less

restrictive acceptance criteria given in Figures #13 and 14, the flaw must be at least a

distance from the nearest surface equal to it’s height. Otherwise, the criteria becomes more

restrictive incrementally as the flaw is positioned nearer the surface. When the flaw is less



than 40% of it’s own height from the nearest surface it is considered to be a surface flaw and

the ligament of sound material between the flaw and the surface is then added to the height

of the flaw.

The criteria devised by Metalogic, whereby a planar flaw is rejected if it’s dimensions

exceed .24” long X .020” height and it is not separated from the nearest surface by at least

.04” to .06” dependent on tube wall thickness, appears to be conservative. This flaw

dimension provides an aspect ratio of ~.05 and would clearly be acceptable for any of the

tube thicknesses involved in this investigation, as shown in Figure #15

Figure #15


Aspect Ratio 0.05


0.031

0.035

0.039

0.043

0.047

0.050

0.054

0.000

0.010

0.020

0.030

0.040

0.050

0.060

0.1

5

0.1

6

0.1

7

0.1

8

0.1

9

0.2

0.2

1

0.2

2

0.2

3

0.2

4

0.2

5

0.2

6

0.2

7

0.2

8

0.2

9Material Thickness (Inches)

Ma

x. F

law

He

igh

t '2

a' (I

nc

he

s)

Max. Flaw Height

Documents

Phased Array UT Versus RT Report Truncated