determination of an optimal examination grid for the

ECNDT 2014 Dr. Johannes Vrana

Determination of an Optimal Examination Grid

for the Automated Ultrasonic Inspection of Heavy Rotor Forgings

DGZfP Committee Ultrasonic Testing

Subcommittee Automated UT


Automated Shaft Inspection SystemSaarschmiede, Völklingen


Terms

Dx

dx

dy

Dy Scan directionInd

ex

dire

ctio

n

•dx: Increment in scan direction(Defined by pulse repetition rate and examination speed)

•dy: Distance between two adjacent laps in index direction

•Dx, Dy: Dimensions of the ultrasonic beam


Automatisierte Disc Inspection SystemSchmiedewerke Gröditz


Automated Shaft Inspection SystemGE Sensing & Inspection Technologies, Alzenau


Automated Shaft Inspection SystemKARL DEUTSCH Prüf- und Messgerätebau GmbH + Co KG, BGH Siegen


Determination of an Optimal Examination Grid for the Automated Ultrasonic Inspection of Heavy Rotor Forgings

� Introduction & Motivation

� Requirements in Current

Standards

� Definition of an Examination Grid

� Normalized Grid Rating Rn

� Average Grid Rating Rd

� Determination of the Ultrasonic

Beam Dimensions

� Determination of the Examination

Grid

� Summary



•Required for heavy rotor forgings

•Limited optimization regarding flaw reflection

•Recorded in distinct pattern

•Full volume coverage required

Automated UT Multiple Scans

•Required by VGB-R 504 M

Low Sound Attenuation

⇒ Limited pulse repetition rates

⇒ Limited inspection speed

⇒ Cost of ultrasonic inspection depends directly on examination grid(both in scanning and index direction)

⇒ High inspection duration





Standards





Beam Dimensions


Grid

� Summary


Requirements in Current StandardsEN 10228-3:1998 - Non-destructive testing of steel forgings

Dx

dx

dy

Dy Scan directionInd

ex

dire

ctio

n

Requirement

•Overlap of at least 10% of the effective active element size

•No requirement in scan

direction

Issues for AutoUT

•Apparently assumes a high pulse-repetition-rate and slow probe movement.

•Shape and size of the

sound bundle not considered


Requirements in Current StandardsEN 583-1:1998 - Ultrasonic examination - General principles

Requirement

•Based on size of -6 dB beam

•Requirement in scan and index direction

•The beam of two adjacent -6 dB beams

have to touch

Issues for AutoUT

•Some zones are not inspected with the required sensitivity

•No formulas provided how to determine an examination grid

Dx

dx

dy

Dy


Requirements in Current StandardsASTM E 2375 - 08 - Ultrasonic Testing of Wrought Products

Requirement

•Based on size of -6 dB beam

•Index direction: Overlap of at least 20% of the effective beam width size

•Scan direction: Scanning speed limited by

detectability of the reference reflectors

Issues for AutoUT



Dx

dx

dy

Dy


Requirements in Current StandardsSummary

•Overlap of at least 10% of the effective active

element size

EN 10228-3 SEP1923 IIW Handbook

•Overlap of at least 15% of the active element size

•The beam of two adjacent -6 dB beams have to touch

EN 583-1

•No requirement in scan direction (or only by limitation of scanning speed)

•Overlap of the beams – however not considering the volume to be inspected

•Unclear:

• Effective element size• Transducer width



ASTM E 2375

•Overlap of at least 20% of the effective beam width

size

ASTM A 418

•Indexing by 75 % of the transducer width



•Required for heavy rotor forgings

•Limited optimization regarding flaw reflection

•Recorded in distinct pattern

•Full volume coverage required

Automated UT Multiple Scans

•Required by VGB-R 504 M

Low Sound Attenuation

⇒ Limited pulse repetition rates

⇒ Limited inspection speed

⇒ Cost of ultrasonic inspection depends directly on examination grid(both in scanning and index direction)

Motivation •Existing standards define examination grids for manual inspection⇒ Not simply transferable to automated

⇒ High inspection duration

⇒ Start of development of an Optimal Examination Grid for the Automated Ultrasonic Inspection


DGZfP Committee Ultrasonic TestingSubcommittee Automated UT

Peter Archinger, GMH Prüftechnik, Nürnberg Otto Alfred Barbian, Blieskastel Dr. (USA) Wolfram Deutsch, Karl Deutsch, Wuppertal

Dr. sc. techn. Peter Kreier, Innotest, Eschlikon/CHRoland Reimann, AREVA NP, Erlangen

Udo Schlengermann, Erftstadt Herbert Willems, NDT Syst. & Services, Stutensee

Kay Drewitz, Schmiedewerke, GröditzDr.-Ing. Alexander Zimmer, Saarschmiede, Völklingen

Frank W. Bonitz, Westinghouse, Mannheim Mathias Böwe, BASF SE, Ludwigshafen Klaus Conrad, Siemens AG Energy, Mülheim

Dr.-Ing. Werner Heinrich, Siemens AG Energy, Berlin Dr. Johannes Vrana, Siemens AG Energy, München

Dr. Gerhard Brekow, BAM, Berlin Wolfgang Kappes, Fraunhofer IZFP, Saarbrücken Hans Rieder, Fraunhofer ITWM, Kaiserslautern

UT System Manufacturers

Forging Manufacturers (Users)

OEM

Research Institutes





Standards

� Definition of an Examination

Grid



� Determination of the Ultrasonic Beam Dimensions

� Determination of the Examination Grid

� Summary


•Longitudinal section through adjacent beams

Definition of an Examination GridSituation

B: At the end of the near field

C: At 3.5 times near field

Longitudinal Section

A: Directly at the probe

Horizontal Section


Definition of an Examination GridNormalized Grid Rating Rn

Definition of Rn

2

2

2

21

y

y

x

x

nD

d

D

d

R+=

•dx: Increment in scan direction•dy: Distance between two adjacent laps in index direction•Dx, Dy: Dimensions of the ultrasonic beam

Rn = 1 – Gapless (at least single sampling)

dx

dy

Dx

Dy



Definition of Rn

2

2

2

21

y

y

x

x

nD

d

D

d

R+=


Rn = 2 – At least double sampling

dx

dy

Dx

Dy



Definition of Rn Rn = 0,5 – Beams touching

2

2

2

21

y

y

x

x

nD

d

D

d

R+=

Rn = 1 - Gapless

Rn = 2 – Double Sampling Rn = 4 – Quadruple Sampling

0 1 2 3 4 5 6 7

Overlap:•dx: Increment in scan direction•dy: Distance between two adjacent laps in index direction•Dx, Dy: Dimensions of the ultrasonic beam





Standards

� Definition of an Examination

Grid



� Determination of the Ultrasonic Beam Dimensions

� Determination of the Examination Grid

� Summary


4

π⋅⋅=

y

y

x

xd

d

D

d

DR

Definition of an Examination GridAverage Grid Rating Rd

Definition of Rd


Area of -6 dB beamRd = ----------------------------

Area of ex. grid

Example: Rd = 1

-6 dB beam

dx

dy

Dx

Dy

ExamintionGrid



Definition of Rd Rn = 1; Rd ≈ 1.81


4

π⋅⋅=

y

y

x

xd

d

D

d

DR

Rn = 1; Rd ≈ 1.57

⇒ OptimizedExamination Grid


4

π⋅⋅=

y

y

x

xd

d

D

d

DR


Definition of Rd


•Optimized examination grid in the case of:

( )n

xx

R

Dd

⋅=

2 ( )n

y

yR

Dd

⋅=

2

Optimized Examination Grid

and

Optimizing the Examination Grid

0,00

1,00

2,00

3,00

4,00

5,00

6,00

7,00

8,00

9,00

10,00

0,00 0,10 0,20 0,30 0,40 0,50 0,60 0,70 0,80 0,90 1,00

dx/Dx

du

rch

sch

nit

tlic

he R

aste

rgü

te R

d

Rn = 1

Rn = 2

Rn = 3

Rn = 4

Av

era

ge G

rid

Rati

ng

Rd





Standards





Beam Dimensions


Grid

� Summary


•Longitudinal section through adjacent beams


B: At the end of the near field

C: At 3.5 times near field

Longitudinal Section

A: Directly at the probe

Horizontal Section

Grid Rating

2

2

2

21

y

y

x

x

n D

d

D

d

R+=

4

π⋅⋅=

y

y

x

xd

d

D

d

DR


Definition of an Examination GridHow to calculate the sound bundle – Basic Situation

Normal Straight Beam Probe on a Plane Surface

( )2 tanD s ϕ= ⋅ ⋅

62

xD FB= ⋅ 62yD FL= ⋅

Dual Element Probe on a Plane Surface

•dx: Increment in scan direction•dy: Distance between two adjacent laps in index direction•Dx, Dy: Dimensions of the ultrasonic beam•s: Soundpath•FB6, FL6: Focal Width & Length


•Different scans required


axial

radial radial / axial

radial / tangential

radial / tangential

radial

axial / tangential

axial/ radial

axial/radial

Scans



Situation

Plane Convex Concave

Normal

Dual Element

Angle


•Probe moved on the surface of the component

•Examination grid dx an dy established at the surface

•Beam changes within the part

Definition of an Examination GridHow to calculate the sound bundle

Angle Probe on a Plane Surface

Dx‘

s

α

φ φ

⇒ For the calculation of the examination grid the

projection of the beam to the surface is necessary

( ) ( )( ) ( )αϕ

ϕα

⋅+⋅

⋅⋅⋅⋅=

2cos2cos

2sincos2'

sD x


•Probe moved on the surface of the component

•Examination grid dx an dy established at the surface

•Beam changes within the part


Angle Probe on a Plane Surface

Dx‘

s

α

φ φ

( ) ( )( ) ( )αϕ

ϕα

⋅+⋅

⋅⋅⋅⋅=

2cos2cos

2sincos2'

sD x

( )2 tany

D s ϕ= ⋅ ⋅



Situation


Normal

Dual Element

Angle



Normal Straight Beam Probe on Convex Surface

( )2 tanD s ϕ= ⋅ ⋅

62


Dual Element Probe on Convex Surface

1

1

1

' arcsin sin( )2 180

x

DD D

D s

πϕ ϕ

= ⋅ ± ⋅ ⋅ − ⋅ °

1

1

'2

x

x

D DD

D s

⋅=

− ⋅Corrected by:

( )2 tanyD s ϕ= ⋅ ⋅


•E.g. from the outer diameter surface D1


Angle Probe on a Convex Surface

D‘+

D1

D‘-ϕ

α

ϕ

( )

1 1 1

2 2

1 1

1

1

1

2 2' arcsin sin( ) arcsin sin( ) 2

180 2

with ( 2) 2 ( 2) cos( )

2sin( ) for 0

and 2sin for 0

2sin for 0

x

D D DD

r r

r s D s D

D

r D

D

πα ϕ α ϕ ϕ

α

α ϕ α

ϕ α

α ϕ α

= ⋅ + − − ± ⋅ ⋅ ⋅

°

= + − ⋅ ⋅ ⋅

+ >

≥ =

− <

1

1

' in the case /2 cos( )

and ' in the case

wit

/ 2 cos( )

h D s D

D s D

α

α

+

−

> ⋅

≤ ⋅

( )2 tany

D s ϕ= ⋅ ⋅



Situation


Normal

Dual Element

Angle



Normal Straight Beam Probe on Concave Surface

62


Dual Element Probe on Concave Surface

Corrected by:

( )2 tanyD s ϕ= ⋅ ⋅

22

2


x

DD D

D s

πϕ ϕ

= − ⋅ ⋅ ⋅ − ⋅ °

( )2

2

'2

x

x

D DD

D s

⋅=

+ ⋅


•E.g. from the inner diameter surface D2


Angle Probe on a Concave Surface

( )2 tany

D s ϕ= ⋅ ⋅

( )

2 2 2

2 2

2 2


180 2

with ( 2) 2 ( 2) cos( )

x

D D DD

r r

r s D s D

πα ϕ α ϕ ϕ

α

= ⋅ + − − + ⋅ ⋅ ⋅

= + + ⋅ ⋅ ⋅



Situation


Normal

Dual Element

Angle





Standards





Beam Dimensions

� Determination of the

Examination Grid

� Summary


•For each scan•Normalized Grid Rating Rn (gapless recommended)•Examination zone

•Minimum soundpath s1

•Maximum soundpath s2

Determination of the Examination Grid

Necessary Specifications


•For each scan•Normalized Grid Rating Rn (gapless recommended)•Examination zone

•Minimum soundpath s1

•Maximum soundpath s2


Necessary Specifications

Determination of Examination Grid

•Calculation of the projection of the sound bundle dimensions both for s1 and s2

•s1 : Dx1, Dy1

•s2 : Dx2, Dy2

•Calculation of the optimized examination grid both for s1 and s2 considering the specified normalized examination grid rating Rn

•s1 : dx1, dy1

•s2 : dx2, dy2

•Selection of the actually used examination grid dx and dy


•Calculation of the projection of the sound bundle dimensions both for s1 and s2

•s1 : Dx1, Dy1

•s2 : Dx2, Dy2

•Calculation of the optimized examination grid both for s1 and s2 considering the specified normalized examination grid rating Rn

•s1 : dx1, dy1

•s2 : dx2, dy2

•Selection of the actually used examination grid dx and dy


Determination of Examination Grid

Check of Examination Grid

•OK if both selected values are not bigger than the calculated values•dx vs. dx1, dx2

•dy vs. dy1, dy2

•Otherwise needs to be tested by calculating Rn using dx and dy for both Dx1, Dy1 and Dx2, Dy2


Scan s1 s2 D‘x1 D‘x2 Dy1 Dy2 Rn dx1 dx2 dy1 dy2 dx dy Rn1 Rn2

(mm) (mm) (mm) (mm) (mm) (mm) (mm) (mm) (mm) (mm) (mm) (mm)

Faces, axial, straight 100 300 1

D1 = 1500 mm, D2 = 300 mm, L = 300 mm

°

Determination of the Examination GridExample

Disc

Examination Grid




Faces, axial, straight 100 300 12.9 38.8 12.9 38.8 1

D1 = 1500 mm, D2 = 300 mm, L = 300 mm

°


Disc

Examination Grid




Faces, axial, straight 100 300 12.9 38.8 12.9 38.8 1 9.1 27.4 9.1 27.4

D1 = 1500 mm, D2 = 300 mm, L = 300 mm

°


Disc

Examination Grid




Faces, axial, straight 100 300 12.9 38.8 12.9 38.8 1 9.1 27.4 9.1 27.4 9 9

D1 = 1500 mm, D2 = 300 mm, L = 300 mm

°


Disc

Examination Grid




Faces, axial, straight 100 300 12.9 38.8 12.9 38.8 1 9.1 27.4 9.1 27.4 9 9 1.03 9.3

D1 = 1500 mm, D2 = 300 mm, L = 300 mm

°


Disc

Examination Grid





Faces, axial/tang., 45° 100 424 13.4 40.1 6.6 19.9 1 9.5 40.1 4.7 19.9 9 4.5 1.09 9.8

OD, radial, straight 120 600 20.4 393 15.5 77.6 1 13.1 280 11.0 55 13 10.5 1.05 52

OD, radial, straight, dual-element,

5 120 1

OD, radial/tang., 14° 120 728 2

OD, radial/tang., 45° 350 1061 1

D1 = 1500 mm, D2 = 300 mm, L = 300 mm

°


Disc

Examination Grid





Faces, axial/tang., 45° 100 424 13.4 40.1 6.6 19.9 1 9.5 40.1 4.7 19.9 9 4.5 1.09 9.8



12 5 14 1 3.6 9.9 3.5 10 1.02

OD, radial/tang., 14° 120 728 2

OD, radial/tang., 45° 350 1061 1

D1 = 1500 mm, D2 = 300 mm, L = 300 mm

°


Disc

Examination Grid





Faces, axial/tang., 45° 100 424 13.4 40.1 6.6 19.9 1 9.5 40.1 4.7 19.9 9 4.5 1.09 9.8



5 120 5 14 1 3.6 9.9 3.5 10 1.02

OD, radial/tang., 14° 120 728 21.3 - 15.5 - 2 9.6 - 7.8 - 9.5 7.5 2.1 -

OD, radial/tang., 45° 350 1061 1

D1 = 1500 mm, D2 = 300 mm, L = 300 mm

°


Disc

Examination Grid





Faces, axial/tang., 45° 100 424 13.4 40.1 6.6 19.9 1 9.5 40.1 4.7 19.9 9 4.5 1.09 9.8



5 120 5 14 1 3.6 9.9 3.5 10 1.02

OD, radial/tang., 14° 120 728 21.3 - 15.5 - 2 9.6 - 7.8 - 9.5 7.5 2.1 -

OD, radial/tang., 45° 350 1061 161 141 24 70 1

D1 = 1500 mm, D2 = 300 mm, L = 300 mm

°


Disc

Examination Grid





Faces, axial/tang., 45° 100 424 13.4 40.1 6.6 19.9 1 9.5 40.1 4.7 19.9 9 4.5 1.09 9.8



5 120 5 14 1 3.6 9.9 3.5 10 1.02

OD, radial/tang., 14° 120 728 21.3 - 15.5 - 2 9.6 - 7.8 - 9.5 7.5 2.1 -

OD, radial/tang., 45° 350 1061 161 141 24 70 1 114 100 16.4 50

D1 = 1500 mm, D2 = 300 mm, L = 300 mm

°


Disc

Examination Grid





Faces, axial/tang., 45° 100 424 13.4 40.1 6.6 19.9 1 9.5 40.1 4.7 19.9 9 4.5 1.09 9.8



5 120 5 14 1 3.6 9.9 3.5 10 1.02

OD, radial/tang., 14° 120 728 21.3 - 15.5 - 2 9.6 - 7.8 - 9.5 7.5 2.1 -

OD, radial/tang., 45° 350 1061 161 141 24 70 1 114 100 16.4 50 100 17 1.09 1.79

D1 = 1500 mm, D2 = 300 mm, L = 300 mm

°


Disc

Examination Grid





Faces, axial/tang., 45° 100 424 13.4 40.1 6.6 19.9 1 9.5 40.1 4.7 19.9 9 4.5 1.09 9.8



5 120 5 14 1 3.6 9.9 3.5 10 1.02

OD, radial/tang., 14° 120 728 21.3 - 15.5 - 2 9.6 - 7.8 - 9.5 7.5 2.1 -

OD, radial/tang., 45° 120 1061

D1 = 1500 mm, D2 = 300 mm, L = 300 mm

°


Disc

Examination Grid





Faces, axial/tang., 45° 100 424 13.4 40.1 6.6 19.9 1 9.5 40.1 4.7 19.9 9 4.5 1.09 9.8



5 120 5 14 1 3.6 9.9 3.5 10 1.02

OD, radial/tang., 14° 120 728 21.3 - 15.5 - 2 9.6 - 7.8 - 9.5 7.5 2.1 -

OD, radial/tang., 45° 120 1061 28 141 10 70 1 19.9 100 7.1 50 20 7 1.0 33

D1 = 1500 mm, D2 = 300 mm, L = 300 mm

°


Disc

Examination Grid





Standards





Beam Dimensions


Grid

� Summary


•Current standards•Not sufficient for the determination of an examination grid for automated UT

•New DGZfP Guideline “US 07”•Harmonizes the calculation of the examination grid

•Defines•Normalized Grid Rating•Average Grid Rating•How to calculate the UT beam dimensions

•Optimizes the inspection speed

•Can be adopted to other applications


Summary


Thanks for paying

attention to all the

formulas

( )

1 1 1

2 2

1 1

1

1

1


180 2

with ( 2) 2 ( 2) cos( )

2sin( ) for 0

and 2sin for 0

2sin for 0

x

D D DD

r r

r s D s D

D

r D

D

πα ϕ α ϕ ϕ

α

α ϕ α

ϕ α

α ϕ α

= ⋅ + − − ± ⋅ ⋅ ⋅

°

= + − ⋅ ⋅ ⋅

+ >

≥ =

− <

1

1

' in the case /2 cos( )

and ' in the case

wit

/ 2 cos( )

h D s D

D s D

α

α

+

−

> ⋅

≤ ⋅

2

2

2

21

y

y

x

x

nD

d

D

d

R+=

4

π⋅⋅=

y

y

x

xd

d

D

d

DR( ) ( )

( ) ( )αϕ

ϕα

⋅+⋅

⋅⋅⋅⋅=

2cos2cos

2sincos2'

sD x

11

1


x

DD D

D s

πϕ ϕ

= ⋅ ± ⋅ ⋅ − ⋅ °

1

1

'2

x

x

D DD

D s

⋅=

− ⋅

determination of an optimal examination grid for the

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