By

RN Gupta
Sr Prof/Bridge-1
 USFD

• Ultra Sonic Flaw Detection (USFD) Technique is the most popular

Non-Destructive Technique to detect flaw in rails and welds started
in 1960s on IR.

• Technique is used to know -

The Location & Severity of Defect

For
Utilizing Rail/Weld upto maximum optimum life
 Classification of Sound Waves
Classification of Sound Waves based on propagation-

• Longitudinal or Compression waves

• Transverse or Shear Waves

• Surface Waves or Rayleigh Waves

 Classification of Sound Waves

• Longitudinal waves are faster than Transverse waves.

• Their velocity in any given media is approx. half the

velocity of longitudinal Waves.

• Transverse waves are also known as Shear Waves.

 Parameters of Wave

 Frequency

 Wavelength
 Velocity

 Amplitude

 Intensity
 Velocity of Sound Waves

Medium Velocity m/sec

Longitudinal Wave Transverse Wave

Steel 5920 3230

Perspex 2730 1430
Water 1480 -
Air 330 -
 Properties of Sound Wave

• Reflection
• Refraction
• Transformation - Mode Conversion
• Acoustic Impedance
• Attenuation – Absorption & Scattering
 Reflection - Refraction

When an ultrasonic beam strikes at

a boundary between two media at
normal incidence, two phenomena
will occur-

 Reflection at the boundary.

 Transmission through the
boundary.
 Transmission through Inclined Plane

Incident Wave i=r

MEDIUM - I
Reflected Wave
PERSPEX i
Velocity – 2730 m/s (L) r
Surface

MEDIUM - II

Snell’s Law = STEEL
sin i v1 Velocity – 5920 m/s (L)
>i Refracted Wave

sin  v2
 Transformation

• When a longitudinal wave hits an interface of materials

of different accoustic impedance and the incident angle
is not normal to interface-
some of the energy can cause particle
movement in the transverse direction to start a Shear
(transverse) wave.
And Longitudinal wave is split into Longitudinal and
Shear Wave. This is called Transformation or Mode
Conversion of waves.
 Transformation

Incident Wave Reflected Waves

S1 L1
rL Perspex
VL = 2730 m/s
i rS
VS = 1430 m/s
MEDIUM - I
vL=2730 m/s
MEDIUM - II  Steel
vL1=2730 m/s rL = i S
L VL = 5920 m/s
vS1=1430 m/s rS < i L2 VS = 3230 m/s
S2
vL2=5920 m/s L > i
Refracted Waves
vS2=3230 m/s  S> i
 S < L
 Transformation

Incident Wave ic1

L
i PERSPEX, v1
MEDIUM - I

MEDIUM - II 
T L L
STEEL, v2
Ic1 = 27 .70
T = 33.30 T

L = 900 Refracted Wave

 Usable Range of Probe Angles

• First Critical Angle - 27.60

27.60 • Angle of Reflected
Shear wave - 33.30
57.70
L
• Second Critical Angle - 57.70
PERSPEX
900 • Angle of Reflected
STEEL
Shear wave - 900
T
Angle of Shear Wave is known as
33.30 Probe Angle
 Acoustic Impedance

• It is a property of the material which determines its affinity

for propagation of sound waves.

• The acoustic impedance (Z) of a material is defined as the

product of density (ρ) and acoustic velocity (V) of that
material.

Z= ρ V
 Acoustic Impedance

Material Acoustic impedance

(X 107 Kg/m2-Sec )
Z
Air 0.00004
Water 0.149
Machine Oil 0.150
Perspex 0.320
Steel 4.68
 Reflection Index

• More difference in acoustic impedance of interface materials, more

waves will reflect back and less will refract into the second medium.

• Reflection Index 100 % 80 % Reflection

 Z 2  Z1 
2

R   
 Z 2  Z1 20 % Refraction

• USFD testing works on the principle of Refraction of Ultrasonic waves,

hence acoustic impedance difference of two interface materials should
be minimum.
 Reflection Index

Medium 1 Medium 2 % Reflected % Refracted

Steel Air 100 0

Steel Water 88 12
Steel Perspex 76 24
Perspex Water 13.3 86.7
Perspex Air 100 0
Air Water 99.9 0.1
 Transmission and Reception of Sound waves

Transducer / Probe Reflection Index

• Steel-Air = 100%
• Steel-Water = 88%
1 1
Loss 88% 0 .
0 4
Water as Couplant % 4
%
1 Loss 10.56%
2 1
% 2
%
Steel

Air
 Properties of Couplant
Properties of good couplant-
 Good adherence, Adequate viscosity
 Non-corrosive and non-toxic nature.
--------------------------------------------------------------------
---------------------------------

 For RAIL Testing - Water

 For Weld Testing and other Special Testing which require Hand Probing-
Soft Grease OR Any thick oil of High Viscosity Grade
 Loss of Sound Waves-Absorption
 Absorption is the Energy
consumed in the process of
causing vibrations in
particles.

 When sound travels in a

medium, some part of it
is absorbed in medium
and at the boundaries.

63
 Loss of Sound Waves - Scattering

 Scattering is the loss in

dispersion of sound energy
from the particle surface.

 Scattering occurs when

material is not Strictly
homogeneous.

63
 Attenuation
• When sound travel through a medium, its intensity diminishes due to
scattering and absorption, it is called Attenuation.
• Attenuation A = KD3 f4 / V4 Or. KD3 / λ4
K= Constant
D = avg. Grain size of the material,
f = Frequency,
V = Velocity
λ = Wave length

Loss of energy is same for Longitudinal and Shear waves

 Velocity on Longitudinal waves is almost double than the Shear
waves. So, for same grain size, attenuation is same for longitudinal
and Shear waves as Longitudinal waves used in testing are of almost
double frequency than the shear waves.
Probes, Testing
&
Action
 Probe
• Probe is the arrangement used for transmitting and receiving the
ultrasonic energy to and from the rail.
• Probe contains Piezo Electric Transducer which transmits and
receives sound energy.
• It uses Piezoelectric crystals named Lead Zirconate Titanate (PZT)
which exhibits Piezo Electric Effect and converts electrical energy
into sound energy and vice-versa.
 Probes
• It is a metallic housing containing the Crystal, Damping material,
Electrical leads & a Perspex face.

700 Probe 00 Probe

2/4 MHz

450 Probe 700 Side Looking

Probe
 00 Double Crystal Probe

Power Supply Lead

Damping Material

Acoustic Insulating Body

Transmitter Piezoelectric Crystal Receiver Piezoelectric Crystal

Acoustic Barrier
Matching Layer of Perspex

Double Crystal Probe for Testing purpose

 Probes
• Probes can be classified on the basis of -
 Number of crystals
― Single crystal
― Double crystal probes

 Angle of wave transmission

― Normal or 0 Degree Probe
― Angle probe – 370, 450, 700

 Frequency
― 2 MHz
― 4 MHz
 00 Double Crystal Probes - For Testing
• Frequency 2 MHz • Frequency 4 MHz
• Used for Weld testing (Manually) • Used for Rail Testing in Testing Trolley
Reflection : Working Principle of USFD

• High Frequency Sound Waves are

introduced into rails.
• When they come across any flaw,
they are reflected back.
• Reflected sound energy and time
taken in travel are measured and
size & distance of defect can be
deduced.
• These are displayed on screen on
vertical and horizontal scale
respectively.
FLAW DETECTION
 Flaw detection
• Ultrasonic pulses are generated through Probes and introduced into
the rail steel
• When these pulses come across a dissimilar medium like air
void/crack or other material like slag having different acoustic
impedance than steel, they get reflected as Echo.
• Reflected US wave can indicate the location & size of the source of
reflection. This technique is called “ Pulse Echo ” or Reflection
technique.
• Reflected wave will come back only when the sound beam hit the
discontinuity plane normally.
156/172 mm
51 mm

29/31.5 mm
30 mm
30 mm
67/74 mm
Bolt Hole Crack

=370
=370

=530
Rail Testing
Single Rail Testing Machine (SRT)
Double Rail Testing Machine (DRT)
 Probes used in Rail testing
Probe Frequency Crystal Nos Size

00 or NORMAL Probe 4 MHz Double 1 18 mm Circular

700 Center Probe 2 MHz Single 2 20 X 20 mm

Forward/Backward Square
700 Shifted GF Probe 2 MHz Single 2 ---,,---
Forward/Backward
700 Shifted NGF Probe 2 MHz Single 2 ---,,---
Forward/Backward
370 Center Probe * 2 MHz Single 2 ---,,---
Forward/Backward
450 Probe in Test Rig 2 MHz Single 2 ---,,---
Area Covered by Normal (00) Probe
Area Covered by 700 Probe
 Area Covered by 700 Probes

Gauge 4 mm Non-Gauge
Face Face
5 mm
Area Not Covered in Rail Testing

5 mm
4 mm
Scab Rail Test by 450 Test Rig
 Scab Rail Test by 450 Test Rig

(134 mm for 52 kg Rail)

(144 mm for 60 kg Rail)
2 x Rail Head

 Used for detection of Transverse and Vertical longitudinal defects in

Rail Head at the location of wheel burn, scabbed rail etc.
 Defect in Rail

Horizontal Crack in
Horizontal Crack in Head-Web
Head
Junction

Horizontal Crack in Web

Detection By 00 Probe Horizontal Crack in Web-Foot

Junction
 Detection By Gauge Face (Shifted) 700 F/B Probe

Gauge face corner defect

Detection By Non-Gauge (Shifted) Face 700 F/B Probe

Duplicate Flange of Wheel

Non Gauge Face side defect

Detection By 700 F/B Probe

Transverse Flaw or Kidney Flaw

Detection By 370 F/B Probe and 00 Probe

Star Crack or Bolt Hole Crack

 Defect detection By Probes
• Horizontal Flaw
- 00 Probe
• Transverse Flaw
- 700 Probe
• Longitudinal vertical Flaw
- 00 Probe
• Bolt Hole Cracks
- 370 Probe & 00 Probe
• GF/NGF Corner Defects
- 700 Shifted Probe
• Scab/Wheel Burn rail
- 450 Test Rig
 USFD Testing in Manufacturing Plant

Testing in Steel plant is

done by an on line USFD
machine having multiple
probes covering entire rail
section
 USFD Testing in Manufacturing Plant

1 2

3
13 Piezo-electric probes are

4
placed at different locations

7
and defects are displayed in

8
9
different colours.

10
Weld Testing
Digital Weld Tester – Hand testing
 Probes used in Weld testing

Probe Frequency Crystal Nos Size

00 or NORMAL Probe 2 MHz Double 1 18 mm

Circular
700 Probe 2 MHz Single 1 20 X 20 mm
Square
450 Probe 2 MHz Single 1 ---,,---

700 Side looking (SL) Probe 2 MHz Single 2 ---,,---

450 Probe in Tandem Rig 2 MHz Single 2 ---,,---

Head and Web Testing by 00 Normal Probe

Detection of Porosity,
Blow Hole, Slag inclusion
upto mid web
 Attenuation
• When sound travel through a medium, its intensity diminishes due to
scattering and absorption, it is called Attenuation.
• Attenuation A = KD3 f4 / V4 OR KD3 / λ4
K= Constant
D = avg. Grain size of the material,
f = Frequency,
V = Velocity
λ = Wave length

Loss of energy is more in coarse material i.e. welds

 To reduce the attenuation, frequency for weld testing with 00 probe is
kept as 2 MHz. For rail testing, it is 4 MHz.
 Area Covered by 700 Probes

Detection of Lack of
Fusion, Porosity, Blow
Hole, Slag inclusion and
Crack in Head
Gauge Non-
Face Gauge
Face
Flange Testing by 700 Probe

Detection of Lack of
Fusion, Porosity, Blow
Hole and Slag inclusion in
Flange
Area Covered in Flange Testing by 700 Probe
Detection of
Clustered,
Microporosity
or half Moon
Crack in
Bottom of
Flange by 450
Probe
Detection of half
Moon shape
defect in Bottom
of Flange by 700
Side Looking
Probe in case of
presence of Bolt
Hole
Lack of Fusion Testing by 450 Tandem Probes

Tandem Rig
Lack of Fusion Testing by 450 Tandem Probes

Transmitter

Receiver
 Tests for SKV Weld
Initial Acceptance Test & Periodic Test

• 00 2 MHz Double Crystal Probe – Porosity, Blow Hole, Slag inclusion in

Head and upto Mid Web.
• 700 - Lack of Fusion, Porosity, Blow Hole, Slag inclusion, Cracks in Head
- Lack of Fusion, Porosity, Blow Hole, Slag inclusion in Flange
• 450 for foot scanning for clustered defect/ micro porosity and Half Moon
Defect in web foot region.
0
• 70 Side Looking probe for half moon shape defect ( in case of bolt hole)
• 450 Tandem Probe (Two Probes) – Lack of Fusion in Head-Web Junction,
Complete Web and Web-Foot Junction.
Need Based Concept
For USFD testing
 Need Based concept in Periodic Testing

In Need Based concept, inspection frequency is kept low

where defect generation is less, whereas on sections
where defect generation rate is high, the inspection
frequency also gets increased.
Need Based concept in Periodic Testing Chapter-6

• The inspection frequency and condemning defect sizes are related

parameters.
• If the inspection frequency is high, the condemning defect size
can be suitably increased.
• If condemning defect size is large, rails can be allowed in track
for more time, thus service life of rails increases.
• Increase in condemning defect size also enhances the reliability
of inspection, as possibility of non-detection for smaller size
defects is more.
Need Based concept in Periodic Testing Chapter-6

 Increase in Inspection Frequency involves cost, but saving

due to enhanced service life of rails.

 To optimise the cost of testing and rails, the inspection

frequency has to be made dependent on the incidence of
the defects.

 More the possibility of generation of defect, higher should

be the frequency of testing.

 This is known as Need Based Testing.

Frequency of Testing of Rails Para 6.6.1.1 – 6.6.1.2

GMT Frequency Frequency

All ML BG Routes **
Routes
** Main line BG on
CC+8+2 T routes
<=5 2 Years 18 M with 52 kg (90 UTS)
>5 <=8 12 M 9M rail in temperature
>8 <=12 9M 6½M zone III & IV
corresponding to 6
>12 <=16 6M 4½M
GMT traffic
>16 <=24 4M 3M
>24 <=40 3M 2½M
>40 <=60 2M 1½M
>60 <=80 1.5 M 1M
>80 1M 20 Days
 Frequency of Testing of Rails Para 6.6.1
• After the initial USFD testing of rails in rail manufacturing plant, the
subsequent USFD testing needs to be carried out at reduced frequency till
following GMT life-
 Rails rolled after April 1999 – 25 % of Service Life

• Reduced Frequency Period - Every 40 GMT or 8 years whichever is earlier.

Rail Section Service Life for 90 UTS rails

60 Kg 800 GMT ( 1000 GMT for routes
covered by Rail Grinding)
52 Kg 525 GMT

• If rails are not tested in rail manufacturing plant, the reduced frequency
testing period shall not be applicable
 Frequency of Testing of SKV Welds Para 8.15.2
• Initial Acceptance Test – Just after execution
(Not later than 30 days Para 311(3) IRPWM)
• First periodic test – 20 GMT or One year whichever is earlier

• Further tests based GMT Frequency

on route GMT-
0-15 5Y
>15 <=30 4Y
>30<=45 3Y
>45<=60 2Y
>60<=80 1.5 Y
>80 1Y
 Frequency of Testing of Welds Para 8.15.2

• Testing of Conventional AT welds –

 40 GMT or 5 year whichever is earlier

------------------------------------------------------------------------

• On Major Bridges and Tunnels including Approaches 100 m either side

 Testing frequency once in a year.

• Testing Frequency of Defective AT welds

 Double of normal Testing frequency.
 Frequency of Testing of Welds Para 8.15.2

• Weld Testing on Looplines –

Initial Acceptance Test
– Just after execution
First periodic test
– After 1 year
Further tests
– Once in 5 years on Passenger Loops
 Rail Testing : Defects and Action Para 6.4
Classification Painting on Action By USFD Staff Action By P Way Staff
both faces
of web
OBS One Cross SE/JE(P.Way) USFD to Rail/Weld to be provided with
(For Rail) with Red advise sectional clamped joggled fish plate within
Paint SE/JE(P.Way) within 24 3 days.
hrs about the flaw
OBSW location. Keyman to watch during daily
(For Weld) patrolling till it is joggled fish
SE/JE(P.Way)/USFD to plated.
specially record the
observations of the
location in his register in
subsequent rounds of
testing.
 Rail Testing : Defects and Action Para 6.4
classification Painting on Interim Action Action to be taken
both faces
of web
IMR Three SE/JE(P.Way)/USFD shall The flawed portion
(For Rail) Cross impose speed restriction of should be replaced by
with Red 30KMPH or stricter immediately a sound tested rail
Paint and to be continued till flawed piece of not less than
IMRW rail/weld is replaced. 5.5m length (in case of
(For Weld) fish plated track) & 4m
(in case of welded
He should communicate to
track) within 3 days of
sectional SE/JE (P.way) about
detection.
the flaw location who shall
insure that clamped joggled fish
plate is provided with in 24 hrs.
 Rail Testing : Defects and Action Para 6.3

• Any defect or defect at any location which is detected by two

or more probes and are considered to be classified as
OBS/OBSW based on peak pattern of individual probe, should
be classified as IMR/IMRW.

• In case two or more OBS/OBSW defects are located within a

distance of 4.0 metre from each other, such OBS/OBSW
defects shall be classified as IMR/IMRW.
 Rail Testing : Defects and Action

• While testing on Single Line Section and ‘D’ marked rails on

double / multiple line section, additional gain of 10db is to be
employed. Para 4.1.1(c )(iv).

• Rail defects (IMR/OBS) are classified as per increased gain.

However, for weld, defects (IMRW/OBSW) are classified based
on the signal pattern obtained after reducing the gain by 10dB.
Para 4.1.2(b)
 Weld Testing : Defects and Action Para 8.14
Classification Painting on Action to be taken
both faces of
weld (in head)

(i) DFWO-
a) SSE/JE/USFD shall impose SR 30 kmph or stricter
immediately and communicate to sectional SSE/JE about
One circle the flaw location, who shall ensure the following
DFWO with Red b) Protection of defective weld by Joggled Fish Plates
Paint. using minimum two tight clamps immediately with a speed
restriction of 30 kmph. Speed restriction can be relaxed
O to normal after protection by JFP with 2 far end tight bolts
(one on each side) with chamfering of holes, within 3 days.
The joint is to be kept under observation.
 Weld Testing : Defects and Action Para 8.14
Classification Painting on Action to be taken
both faces of
weld (in head)

ii) DFWR –
a) SSE/JE/USFD shall impose SR 30 kmph or stricter
immediately and communicate to sectional SSE/JE
DFWR Two cross about the flaw location, who shall ensure the
with red
paint.
following
b) Protection of DFWR weld by Joggled Fish Plates
using minimum two tight clamps immediately. SR of
30 kmph can be relaxed to normal after providing JFP
with 2 far end tight bolts (one on each side) with
chamfering of holes. The DFWR weld shall be
replaced with in three months of detection.
 Weld Testing : Defects and Action Para 8.10
Classification Painting on Action to be taken
both faces of
weld (in head)

iii) DFWN –
(a) The protection of defective joints (DFWN)
DFWN Two cross
shall be ensured by joggled fish plate with two
with red tight clamps immediately along with proper
paint with N support on wooden block till its removal.
(b) The defective joints (DFWN) shall not be
N allowed to remain in service and shall be
removed within a period of 1 month after initial
USFD testing of AT welds
 Weld Testing : Defects and Action Para 8.14
Adequate traffic block should be granted for removal of DFWR welds. In case of non removal
within three months, a speed restriction of 75 kmph for loaded goods train and 100 kmph for
passenger train should be imposed.

(iii) In case of defective weld (DFWO/DFWR) on major bridges & bridge approach (100m
either side ) and in tunnel and on tunnel approaches (100m either side ), following action
will be taken:-
SE/JE/USFD shall impose speed restriction of 30 Kmph or stricter immediately and
to be continued till defective weld is replaced. He should communicate to sectional
SE/JE (P.Way) about the flaw location who shall ensure the following:-
 Protection of defective weld using clamped joggled fish plate within 24 Hrs.
 The defective weld shall be replaced within 3 days of detection.

• DFWN found in Initial Acceptance Test shall be removed within 1 Month

• More than one DFWO in one weld shall be classified as DFWR Para 8.16(d)
 AT Welding-Action
• After execution of AT weld, welded zone shall be dressed
properly to facilitate placement of probes and to avoid
incidence of spurious signal on the screen.
• The flange of the weld up to a distance of 200mm. on either
side of the weld collar shall be thoroughly cleaned with a
wire brush to ensure freedom from dust, dirt, surface
unevenness etc. Para 8.3
• A thermit welding done in situ shall be joggled fish plated
with two clamps and supported on wooden blocks of 300 -
450 mm length untill tested as good by USFD. Para 8.10
 Check by AEN/SSE (Para-4.3)

• AEN should spend at least few hours (min 2 hours)

each month during his routine trolley inspection with
USFD team and cross check the work including
accuracy setting/ calibration of machine etc.

• SE and SSE should also associate themselves

occasionally.
 Limitations of USFD Testing
• Rails having rust, pitting, hogging, battering of rail end, misalignment of
joints, scabs, wheel burns and other surface imperfections restrict
proper acoustic coupling between probe and rail table and may not
permit detection of flaws.
 Such defects may cause loss of back wall echo and defects below these patches
may remain undetected. Under such circumstances hand probing or Side probing
should be done.
• Severe pipe in the rail may give indication of flaw echo by 0° probe, but
in case of hairline or fine central shrinkage (pipe), negligible drop
occurring in bottom signal may remain unnoticed by the USFD operator
• 450 and 700 SL probes can not detect all half moon cracks in weld.
• Bolt hole cracks propagating vertically downwards or upwards, remain
undetected./
 Limitations of USFD Testing

• Only favourably oriented defects can be detected.

• Only specified defects can be detected.
• A 4 mm deep layer from rail table can not be tested as it
falls in the dead zone of the probe. Similarly, 5 mm
thickness on GF and NGF side can not be tested due to
curvature of rail.
• Cracks lesser than 0.8mm size cannot be detected by the
present arrangement.
Setting –Testing
&
Flaw Classification
 Calibration Chapter-4, Para 4.1.1(b)

• To Know the Exact Location of Defect, X-Axis is

Calibrated with the depth of Defect

• Range – Value for which the total width of screen is

set. Distance travelled by Sound Wave is reflected on
X-axis

• It is done Individually for all the probes used for testing

i.e. 0o, 37o 45o & 70o .

• Done Once in a Week

 70° Probe 45° Probe 0°
Probe
Head
51 mm
700
Beam Length = 172
450
Beam Length 172/Cos 450 = 240

Height 60 Kg = 172 mm
Calibration of Probes – Setting of Range

Probe Calibration Range

00 200 mm (Multi Channel)
300 mm (Multiplexure-
Single Channel)
700 165 mm
370 275 mm
450 275 mm
450 Probe in Test Rig 165 mm
 Sansitivity Setting Chapter-4, Para 4.1(c)

• To Know the Size of Defect , Y-Axis (Screen Height) is Set

with the sensitivity of Defect i.e peak height

• Sensitivity Setting is done once in Three Days

• It is done Individually of all the probes used for testing

– Gain Setting
Testing
of
Weld
Sensitivity Setting for Weld Testing
Standard Weld Piece with Artificial Flaw

3mm dia. hole for 3mm dia. hole for 70 ° Half moon (10mm
70° Head Sensitivity Flange Sensitivity Dia) for 45°
Setting Setting Sensitivity Setting
Procedure for Sensitivity Setting for WeldTesting

Sensitivity Setting for 00 Normal Probe

• Connect the Probe and Recall the channel in which calibration of 00
Probe is saved.
• Place The Probe on Standard Test Piece above 3 mm Ø hole situated 25
mm below the Rail top . Notice the flaw peak appearing from 3 mm Ø hole
• Make the Height of Flaw Echo to 60 % by increasing the Gain.
• Save This Gain for Testing in Section.
• Used to detect Porosity, Blow Hole, Slag inclusion etc in Head and upto
Mid Web.
Sensitivity Setting for 00 Probe

Position ‘A’
60 %

00

5 10
Range 200 mm
 Testing with 00 Probe
1. If any flaw is appeared, adjust the Probe to get the maximum height of
Echo.

2. Classification of Defect as per the peak height and

location
In Head Region- In Web or Foot Region-
Echo Height
40 % to 60 % - DFWO; 20 % to 40 % - DFWO;
> 60% - DFWR > 40% - DFWR
> 30% - DFWN (New weld only) > 20% -DFWN (New weld
only)
 Sensitivity Setting for 700 Probe for Head Testing

• Place The Probe 70 mm away from weld centre. Notice the flaw peak
appearing from 3 mm Through Hole in Head.
• Make the Height of Flaw Echo to 60 % by increasing the Gain.
• Save This Gain for Testing in Section.
Sensitivity Setting for 700 Probe

60%
Position ‘B’
700

5 10
Range 165 mm
Procedure for Head Testing with 700 Probe

1. Place the Probe 140 mm away from Weld Centre facing toward
weld and move Forward Backward upto weld.
2. Classification of Defect as per the peak height and
location-
Height (H) 40% to 60% - DFWO
> 60% - DFWR
> 30% - DFWN (New weld only)
Bunch of moving signal > 10% - DFWR
- DFWN (For New welds)
Sensitivity Setting for 700 Probe for Flange Testing

• Place The Probe on Flange (Middle Zone) 180 mm away from weld centre.
• Move the Probe 50 mm Forward-Backward facing towards weld.
• Notice the flaw peak appearing from 3 mm Through Hole in Flange Centre
of Weld.
• Make the Height of Flaw Echo to 60 % by increasing the Gain.
• Save This Gain for Testing in Section.
Procedure for Flange Testing with 700 Probe
Used to detect Lack of Fusion, Porosity, Blow Hole, Slag inclusion in Flange.
1. Place the Probe 180 mm away from Weld Centre facing toward weld
and move Forward Backward upto weld collar.
2. Classification of Defect as per the peak height and location
Height (H) 40% to 60% - DFWO
> 60% - DFWR
> 30% - DFWN (New weld only)
45˚ Probe for Weld Testing

Sensitivity Setting
• Place The Probe on Standard Weld Test Piece 156/172 mm away from
weld centre for 52/60 kg rail..
• Set height of peak appearing from 10X5X2 mm Artificial Saw Cut to 60 %
by increasing the Gain and Save This Gain for Testing.

Testing
1. If any flaw is appeared, adjust the Probe to get the maximum height of
Echo.
2. If the height of Flaw Echo > 20% - DFWR
- DFWN (New weld only)
 Sensitivity Setting of Tandem Rig
• Adjust the flaw peak height from rail bottom to 100% and note the
Gain.
• Increase this gain further by 10 dB for testing.
 Testing byTandem Rig
• Move the Probes from one end to the Datum line in tandom. Repeat the
exercise from ther side of weld also.

• Testing is done with 10 db increased gain

• Any Flaw peak of ≥ 40% - DFWR
≥ 30% - DFWN (For New Welds)
 Weld Testing : Gain Setting & Defect Classification
Probe Gain Setting Defect Classification
for % Peak
Weld Testing - 00 Head 40-60 % DFWO, > 60% DFWR
≥ 30% DFWN
Web & Foot 20-40 % DFWO, > 40% DFWR
≥ 20% DFWN
700 60 % Head 40-60 % DFWO, > 60% DFWR
≥ 30% DFWN
Flange 40-60 % DFWO, > 60% DFWR
≥ 30% DFWN
450 ≥ 20% DFWR, DFWN

700 SL Probe ≥ 20% DFWR

450 Probe in Tandem Rig 100 % ≥ 40% DFWR; ≥ 30% DFWN

(Testing with 10db additional gain)
Sensitivity Setting for Rail Testing
Standard Test Piece with Artificial Flaw

5 mm Ø
Flat Bottom Hole

15 mm

70˚
12 mm Ø
Through Hole
Procedure for Sensitivity Setting for Rail Testing

Sensitivity Setting for 00 Normal Probe Para 4.1.2 (a)

• Move the Machine on Rail and notice the Back echo from bottom of rail
• Make the Height of Back Echo to 100 % by increasing the Gain.
• Save This Gain for Testing in Section.
Procedure for Sensitivity Setting for Rail Testing

Sensitivity Setting for 700 Central ProbePara 4.1.2 (b)

• Move the Machine on Standard test piece of rail directing towards the 12
mm dia. through hole
• Maximize the Moving peak and set the height to 60 % by adjusting the
Gain.
• Repeat this Procedure for Backward Probe and Save these gains
Procedure for Sensitivity Setting for Rail Testing

Sensitivity Setting for 700 GF/NGF ProbePara 4.1.2 (c)

• Move the Machine on Standard Test Piece directing towards the 5 mm
dia. Flat Bottom Hole
• Two Moving peaks will appear on screen 1st of Flat Bottom Hole and 2nd
of inclined face.
• Maximize this 1st Moving peak of Flat Bottom hole and set the height to
60 %
• Repeat this Procedure for Backward Probe and Save gains.
• Repeat the Same Procedure for Non Gauge Face Forward & Backward
Probe.
 Procedure for Rail Testing Para 4.1.1(c)(iv) & 4.1.2(b)

700 Central Probe-

 On Single line and ‘D’ marked rails, additional gain of 10 dB is to be used

while Rail Testing.

 Rail Defects (IMR/OBS) on single line and ‘D’ marked rails to be

classified on the basis of this 10 dB increased Gain.

 However, for Weld Defects during Rail Testing (IMRW/OBSW),

classification to be done by reducing the gain by 10 dB.
Sensitivity Setting for Rail Testing by 370 Probe
Standard Test Piece with Artificial Flaw
Procedure for Sensitivity Setting for 370 Probe

Sensitivity Setting for 370 ProbePara 4.1.2 (e)

• Move the Machine on Standard test piece of rail directing towards the 5
mm Saw cut on 32 mm dia. hole
• Two peaks will appear, one from hole (3.6/4.6 Div for 52 kg) and other from
5mm saw Cut (4/5 Div for 52 kg) .
• Set the height from 5mm Saw Cut to 60 % by adjusting the Gain.
• Repeat this Procedure for Backward Probe
• Save these gain settings for testing.
Procedure for Sensitivity Setting for Test Rig

Sensitivity Setting for 450 Probe in Test Rig

• Place Test Rig at 20 mm below rail table on the side of rail head

• Peak obtained in receiver probe should be set to the 100% of Full Screen
Height by adjusting the Gain
Test Rig
 Sensitivity Setting of Probes – Gain Setting

Probe Gain Setting Defect Classification

for % Peak
Rail Testing - 00 As per Annexure IIA & IIB
100 %
450 Probe in Test Rig

700 & 370 60 %

Classification of
defects
in
rail testing
(Annexure IIA & IIB)
 Testing by 00 Normal Probe

Location Signal Defect

Classification

1. Within FP Area IMR

No Back Echo or Drop in Back
2. Outside FP area at Echo with or without Flaw Echo
Vulnerable locations
3. Outside FP area at other No Back echo and Flaw Echo ≥ 20 IMR
locations mm length

No Back echo and Flaw Echo < 20 OBS

mm length
4. In FB/AT Weld at IMRW
Vulnerable locations No Back echo and Flaw Echo
moving or without moving OBSW
5. At other locations
 Testing by 450 Test Rig

Location Signal Defect

Classification

1. At other locations Loss of Signal Height ≥ 20 % OBS

Loss of Signal Height ≥ 80 % IMR

2. At Vulnerable Loss of Signal Height ≥ 20 % IMR
locations
Vulnerable i. In tunnel & on tunnel approaches (100 m either side)
Locations- ii. On major bridges & bridge Approaches (100m either side)
iii. In the vicinity of holes near the weld (50 mm for old AT weld
and 75mm for new AT weld from the center of weld on
either side of weld)
 Testing by 700 Central Probe
1. Any transverse defect in the rail head at track locations other than
Vulnerable locations
100 100
90
H ≥ 30; < 50 & V ≥ 20 H ≥ 50 & V ≥ 60) 90
80
80
Flaw Peak Height (V) in %

IMR
70
70% 70
OBS
60
Non Reportable

60
50
H ≥ 50 & V ≥ 20; < 60 50
40
OBS 40
30
(H < 30)

30
20
(V < 20) 20
10
Non Reportable*# 10
0 10 20 30 40 50 60 70 80 90 100 0 1 2 3 4 5 6 7 8 9 10
Extent of movement of flaw echo on horiz. scale (H) in %

2. Vulnerable Locations – OBS zone is also marked as IMR

 Testing by 700 Central Probe
For all single line sections & ‘D’ marked rails on Double/ Multiple line
sections

1. Any transverse defect in the rail 100

90
head at track locations other than

Flaw Peak Height (V) in %

80
Vulnerable locations 70
H < 50 & V ≥ 20
IMR
OBS H ≥ (50≤H
50 & V ≥≤20)
60 100;
20IMR
≤ V ≤100)
50
1. Vulnerable Locations – OBS zone is 40
also marked as IMR 30
20
10 V < 20 ; Non Reportable
0 10 20 30 40 50 60 70 80 90 100

Extent of movement of flaw echo on horiz. scale (H) in %

 Testing by 700 GF/NGF Probe
1. Any transverse defect in the rail head at track
locations other than Vulnerable locations
100 100
90
H ≥ 15; < 30 & V ≥ 20

H ≥ 30 & V ≥ 60) 90
80
80
Flaw Peak Height (V) in %

IMR
Non Reportable

70
70
OBS

60
(H < 15 )

60
50 55%
H ≥ 30 & V ≥ 20; < 60 50
40
40
30 OBS
30
20
(V < 20) 20
10
Non Reportable 10
0 10 20 30 40 50 60 70 80 90 100 0 1 2 3 4 5 6 7 8 9 10
Extent of movement of flaw echo on horiz. scale (H) in %

2. Vulnerable Locations – OBS zone is also marked as IMR

 Rail & Weld : Gain Setting & Defect Classification
Probe Gain Setting for % Defect Classification
Peak
Rail Testing - 00 100 % As per Annexure IIA & IIB
700 60 %
370 60 %
450 Probe in Test Rig 100 %
Weld Testing - 00 60 % Head 40-60 % DFWO, > 60% DFWR, ≥ 30% DFWN
Web & Foot 20-40 % DFWO, > 40% DFWR, ≥ 20% DFWN
700 60 % Head 40-60 % DFWO, > 60% DFWR, ≥ 30% DFWN
Flange 40-60 % DFWO, > 60% DFWR, ≥ 30% DFWN
450 60 % ≥ 20% DFWR, ≥ 20% DFWN
700 SL Probe 60 % ≥ 20% DFWR
450 Probe in Tandem 100 % ≥ 40% DFWR; ≥ 30% DFWN
Rig (Testing with 10db additional gain)