Principles of NDT Methods on Railway AxlesSheet 1 of 38

Principles of NDT Methods on Railway Axles

Dipl.-Ing. Thomas Heckel, BAM VIII.43

Dipl.Ing. Uwe Völz, BAM VIII.43Dipl.-phys. Rainer Boehm, BAM VIII.42

11.10.2010

Principles of NDT Methods on Railway AxlesSheet 2 of 38

1. Introduction

2. NDT by manufacturer

3. In-service inspection

4. In-service inspection

5. Signal processing

Principles of NDT Methods on Railway AxlesSheet 3 of 38

Highspeeds

Testing and diagnostics strategy based on mechanised testing facilities that

enable the in situ and ex situ testing of wheelsets

More frequent testing

High levels of dynamic stress

Time-consumingremoval of wheelsets

Complex vehicle design

Introduction

Principles of NDT Methods on Railway AxlesSheet 4 of 38

1 - Inspection of wheel rims

2 - Inspection of wheel discs

3 - Inspection of axle shafts

4 - Inspection of axles with longitudinal drilled hole

5 - Inspection of rails

1 23 4

5

Automatic Testing on Railway Components

Inspection after manufacturing

Principles of NDT Methods on Railway AxlesSheet 5 of 38

FlawFlaw

F

Am

plit

ude

soundpath

A-Scan

R

Am

plit

ude

Soundpath

A-Scan

F

Am

plit

ude

Soundpath

A-S

Ultrasonic Testing on Railway Axles

R

Riss

Soundpath GateAmplitude Gate

F2

Inspection after production In-service inspection

Principles of NDT Methods on Railway AxlesSheet 6 of 38

1. Introduction

2. NDT by manufacturer

3. In-service inspection

4. In-service inspection

5. Signal processing

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Automated Inspection after Production

Flaw

F

Am

plit

ude

Soundpath

A-Scan

R

R

Inspection after production

Goal:

Find flaws caused by production process,Volumetric defects,non-metal inclusions, shrinking holes

Testing technique:

unfocused normal beam probe,Longitudinal wave, Frequency 2 MHz to 4 MHz,imersion technique

Acceptance criteria:

Amplitude height (DAC)Recording level DSR 2 mm or 3 mm

Principles of NDT Methods on Railway AxlesSheet 8 of 38

Boundary conditions for UT inspection after production

Inspection has to be performed on complex geometries

In the area close to the surface UT sensitivity is reduced (additional MT inspection)

2D-movement of probes is necessary to adapt to curved surface

Inspection has to be finished in less than 15 minutes

Question: Is there a way to improve UT inspection in production?

Principles of NDT Methods on Railway AxlesSheet 9 of 38

High resolution measurements on axle (laboratory)

Resolutionration of scan 0,1 mm by 0,1 mm

Recording level DSR 0,125 mm

Probe used:

Frequency = 10 MHzFocus = 100 mmDiameter = 10 mm

Principles of NDT Methods on Railway AxlesSheet 10 of 38

Sizing of typical volumetric flaws can be performed down to DSR 0,2 mm,

v = vj

v = vj + 12 dB

v = vj + 24 dB

High resolution measurment for in-service inspection (laboratory)

*)Measrements performdedon similar specimen

Principles of NDT Methods on Railway AxlesSheet 11 of 38

1. Introduction

2. NDT by manufacturer

3. In-service inspection

4. In-service inspection

5. Signal processing

Principles of NDT Methods on Railway AxlesSheet 12 of 38

Automated in-service inspection system for hollow axles

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In-service inspection of hollow axle

Flaw

Am

plit

ude

Schallweg

A-Bild

F

Am

plit

ude

Soundpath

A-Scan

Crack

Soundpath gateAmplitude gate

F2

In-service inpsection

Goal:

Find defects caused by operation,find crack-type flaws

Testing technique:

Unfocused angle beam probes,Typical angles of incidence: 38, 45°, 70°Frequency 4 MHz or 5 MHz

Acceptance criteria:

Gate mode for amplitude and soundpath,recording level SCD 2mm

Principles of NDT Methods on Railway AxlesSheet 14 of 38

α = 45°

Inner surface

Outer surface

Center

R35

R85

–R

90

Geometries and soundfields at three-center curves

Principles of NDT Methods on Railway AxlesSheet 15 of 38

Inner surface

Outer surface

Typical indications of geometry change

Saw cut on the shaft Saw cut on curve

Ro

tation

Soundpath

Ro

tation

Soundpath

Principles of NDT Methods on Railway AxlesSheet 16 of 38

Example: Indications from geometry and flaw

Using only information of the gate signal may reduce information (indication of flaw will be lost)!

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LP = 256 mm

s = 77 mm s = 77 mm

Typical indication from geometry using A-Scan method

Inspection result: Geometry change at end of shaft

Principles of NDT Methods on Railway AxlesSheet 18 of 38

s

u

Comparison: Mounted and unmounted seat

S = 78 mm S = 81 mm

Noise caused by the mounted wheel

Noise removed using gate level 80%

Mounted seat unmounted seat

s

u

Principles of NDT Methods on Railway AxlesSheet 19 of 38

Inspection result: Indication at posit ion= 266 mm

s = 77 mm s = 77 mm

LP = 266 mm

S = 85 mm ! S = 85 mm !

Soundpath of indications is too large – there is no flaw

Principles of NDT Methods on Railway AxlesSheet 20 of 38

1. Introduction

2. NDT by manufacturer

3. In-service inspection

4. In-service inspection

5. Signal processing

Principles of NDT Methods on Railway AxlesSheet 21 of 38

Inspection System Wittenberge Depot

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Priciple of Axle Testing with Phased Array Probes

Phased Array Probe

f = 2,7 MHz

β = 48°Transducer Size: 22 x 20 mm2

Number of Elements: 14 Angle of Incidence: 28°to 72°

Principles of NDT Methods on Railway AxlesSheet 23 of 38

Delay Time Distribution

N

Electronic Change

of Angle of Incidence

Delay Time Distribution

N

Electronic Changeof Point of Focus

Electronic Change of

Position of Soundbeam

Position of Active Elements

N

Possibilities of Phased Array Inspection Systems

ScanAngle Focus

Principles of NDT Methods on Railway AxlesSheet 24 of 38

COMpact Phased Array Systems – developed by BAM

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Development and Simulation of Probes

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Simulation Results for Soundfields

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Wheel Disc

Prototype of Phased Array Probe

Phased Array Probe

Area of Interest

Axle

Couplant (Water or Oil)

Principles of NDT Methods on Railway AxlesSheet 28 of 38

Displaying Measured Data

PK

Principles of NDT Methods on Railway AxlesSheet 29 of 38

O°

51.4°

102.8°

154.1°

205.5°

256.9°

308.3°

359.7°

121.6

162135

180

150

200

167

222

186

248

208

277

234

312

245

314

295

380

343

440

mm

α = 42° 45° 48° 51° 54° 57° 60° 63° 67° 70°

1a

3a

5a

2a

6a

8a

9a

48

5C

A

B

Results of Testing the Prepared Wheelset

5a 5a 5a

3a 3a

2a 2a

1a4a 4a 4a

Principles of NDT Methods on Railway AxlesSheet 30 of 38

Concept for Test-System

Wheelset with three brake discs

Areas of interest

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Positioning of Phased Array Probes

PK 4PK 1 PK 2PK 3 PK 6PK 5

Testing with six phased array probes

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Example inspection data from a test shaft with reference defects

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1. Introduction

2. NDT by manufacturer

3. In-service inspection

4. In-service inspection

5. Signal processing

Principles of NDT Methods on Railway AxlesSheet 34 of 38

B2S

Wheeldisk Ø = 1400 mmRF data recordSize of picture 1300 by 1300 mm2

B – Scan Signal processing

Signal processing for disks and axles using RF data 1/2

Principles of NDT Methods on Railway AxlesSheet 35 of 38

B – Scan Signal processing

Signal processing for disks and axles using RF data 2/2

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PA-beam probe using angles-12°to 51°in steps of 7°Longitudinal wave5 MHz

Volumetric flaw in front of backwall

Simulation of ultrasond images using RF data

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Measurements on specimen using phased array

B-Scan Signal processing

Probe: Array type with 16 Elements, Frequency 4 MHz, Angle of incidence 35°to 70°Transversal wave

Principles of NDT Methods on Railway AxlesSheet 38 of 38

Thank you!

Bundesanstalt für Materialforschung und -prüfung

Fachgruppe VIII.4Zerstörungsfreie Prüfung, elektrische VerfahrenUnter den Eichen 83-87D - 12200 Berlin

Dipl.-Ing. Thomas Heckel ���� ++49 (0) 30 8104 3686 ���� Thomas.Heckel@bam.de