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Visual Testing ( VT )
Penetrant Testing ( PT )
Magnetic Particle Testing ( MPT )
Ultrasonic Testing ( UT )
Radiography Testing ( RT )
Eddy Current Testing ( ECT )
Leak Testing ( LT )
Accoustic Emission Testing ( AET )
Thermal Infra Red ( TIR )
Neutran Radiographic Testing ( NRT )
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REQUIREMENTS OF NDT PERSONNELQUALIFICATION
SNTTC1A - Recommended Practice for Non-destructiv
Testing Personnel Qualification and Certification
ASNTCP189 - ASNT Standard for Qualification and Certificatio
Of Non-destructive Testing Personnel.
ASNT - American Society For Non-destructive Testing Personnel.
ISNT - Indian Society For Non-destructive Testing Personnel.
LEVEL OF QUALIFICATION
Level I - Operator
Level II - Inspector / Interpretor
Level III - Authorise to write a NDT procedure and Training &
Certification of NDT Personnel.
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LIQUID PENETRANT TEST ( LPT )
History - Oil & Whiting Method For Rail Road
Principle - Capillary Action of Penetrant&
Blotting Action of Developer
Application - To detect the discontinuities (e.g. Cracks,Seams, Laps, Lamination & Porosity etc.) open to thesurface in non porous materials.
Equipment
.Cleaner - Solvent or Water
. Penetrant - Oil base with Dye
. Developer - Chalk powder
Addition of the above Linen cloth, Cotton waste orabsorbent paper for cleaning purpose.
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BASIC STEPS INVOLVED IN LPT
.SURFACE PREPARATION / PRE- CLEANING
.PENETRANT APPLICATION
.EXCESS PENETRANT REMOVAL
.DEVELOPER APPLICATION
.DEVELOPING TIME
.EXAMINATION & EVALUATION
.RECORDING
.POST-CLEANING
TECHNIQUES(Visible or Fluorescent dye)
I) Water Washable
II) Post Emulsification
III) Solvent Removal
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Properties of Developer
- Blotting Action
- Contrast Background
Properties of Penetrant
-Wetting ability
-Surface Tension
-Capillary
-High fluidity
-Flash point
-Temperature stability
-Visibility
-Volatility
-Corrosive property
i) Sulfur free - for In base alloy
ii) Halogen free - for Austenitic SS and
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TESTING OF PENETRANTS
.Chrome Sensitivity Panel
.Aluminum Comparator Block
.Fluorescence Comparison Test
.Visibility
.Drying Test
LIMITATIONS OF DPT
- Can not give the indication for depth.
- Poor repeatability of test.
-Retest should be done with same type of
penetrant only.
- Not suitable for porous material.
- Not applicable for hidden defects.
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LIQUID PENETRANT STANDARDS
ASME SEC-V (ARTICLE - 22)
SE-165-91
Standard Practice for Liquid Penetrant InspectionMetho
SE-1209-91
Fluorescent Penetrant Examination using water washablprocess.
SE-1219-91
Standard Testing Method for Fluorescent PenetraExamination using Solvent removable Process
SE-1220-91
Standard Test Method for visible PenetrantExamination usingsolvent removable
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PRINCIPLE
Uses Electro-Magnetic Waves of very short wavelengths (X - rays and Gamma Rays) to penetratematerial and the transmitted energy records theimage of discontinuity of the material on the film.
APPLICATIONS
Used on any material, metal & weld to detectsurface of internal detects. Film provides apermanent record.
LIMITATIONS
High Initial cost and potential safety hazard topersonnel.
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SOURCE OF RADIATION
i. Electrically energised equipment. The rays
are called x-rays.ii. Radioactive material. The emitted rays arecalled Gamma Rays.
In x-ray machine the energy level and output can bevaried.
In GammaEquipment the energy level is constant for aparticular type of source and output is constant for andindividual source.
Higher the energy level, greater is the penetratingpower.
HALF LIFE - Strength of source reduces with the timeand when it becomes half of the actual
strength, its known as half life.
Isotopes Half life
Iridium 192 74 days
Thulium 170 128 days
Cobalt 60 5.3 yrs.
Cesium 137 33 yrs
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SENSITIVITY
It is a measure of the ability to detect thesmallest dimension of discontinuity in theradiograph.
Sensitivity is a function of "Definition" and"Contrast".
DEFINITION DEPENDS ON
i. Geometric Un-Sharpness(Penumbra Effect)
ii. Film Grain Size
CONTRAST DEPENDS ON
i. Energy Levelii. Inherent Contrast of Filmiii. Fog Level of Film
iv. Scatter Radiation.
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DENSITY
It is a measure of degree of darkness of film. It is
expressed in 10 Base Log Scale.
DENSITY LIMITS
x-rays - 1.8 to 4.0Gamma Rays - 2.0 to 4.0
ROENTGEN
It is the amount of ionising radiation whichwould produce one Electro static unit of charge ina cubic centimetre of air at standardtemperature (00c) and pressure (760mm Hg)
CURIE
It is a measure of radioactivity or strength osource. It is defined as 3.7 x 1010 Dis-integrations
per second.
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RADIOGRAPHIC TECHNIQUE
1. SINGLE WALL TECHNIQUE
i. Single Shot Technique.ii. Panoramic Technique.
2. DOUBLE WALL TECHNIQUE
i. Double Wall Single Imageii. Double Wall Double Imageiii. Double Wall Superimposed
GEOMETRIC UNSHARPNESS (Ug)
Ug = f x td
where,f = Focal spot size of source of radiation
t = Thickness of object.D = Distance between source of radiation
and the object.
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Ug Limits as per ASME Section V, Article 2
Thickness Range Maximum Ug
Upto2" Thickness 0.020"2" to 3 0.030"3" to 4" 0.040"4" and above" 0.070"
PENETRAMETER
1. WIRE TYPE
I) ASTM STANDARD
II) DIN STANDARD
2. HOLE TYPE
INDUSTRIAL FILMS
I) SLOW SPEED
II) MEDIUM SPEED
III) HIGH SPEED
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RADIOGRAPHIC STANDARDS
ASME - SECTION - V (ARTICLE - 22)
SE94Standard Practice for Radiographic Testing.
SE186Standard Reference Radiographs for Heavy Walled(2" to 4 1/2") Steel Castings.
SE280Standard Reference Radiographs for Heavy Walled(4 1/2" to 12") Steel Castings.
SE - 446Standard Reference Radiographs for Steel Castingsup to 2" Thickness
SE747Standard Method of Controlling Quality ofRadiographic Testing using wire penetrameter.
SE - 1025
Standard Practice for Hole Type image qualityindicators used for Radiography.
SE1079Standard Practice for calibration for Transmission
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Magnetism - A part is magnetized when some or allof the molecules within the parts are aligned.
N S
Random orientation Aligned moleculesof molecules ( Magnetized)n- Magnetized )
CLASSIFICATION OF MATERIAL
.Diamagnetic - Very difficult to magnetized e.g.Hg, Au, Zn, Bi
.Paramagnetic - Accept only slight magnetism
e.g. Al, Cu, wood, Pt , Sullphate
.FerromagnetismCan be magnetized stronglye.g. Fe, Co, Ni,
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MAGNETIC PARTICLEINSPECTION
PRINCIPLE
Uses electrical current or permanent magnetto create a magnetic field in a specimen,andflux leakage occurred at discontinuity.
Magnetic particles cumulate on flux leakageand indicate the discontinuity.
APPLICATIONS
Used on metal which can be magnetised
(Ferromagnetic) to detect surface or sub-surface discontinuities. Simple to use andportable for field testing.
LIMITATIONS
Cannot be used on metals, which cannot bemagnetised.
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CLASSIFICATION OF M.P. TEST METHODS
A. CIRCULAR MAGNETIZATION
1. DIRECT INDUCTION
i. HEAD SHOT METHODBy passing current through the material.
ii. PROD MAGNETIZATION
Where size and location does not permit tuse Head Shot or Central Conductor method
2. INDIRECT INDUCTION
By placing a current carrying conductor into thspecimen.
B. LONGITUDINAL MAGNETIZATION
1. COIL OR SOLENOID METHOD
When the length of specimen is several time
its diameter or cross section - this method used by placing it length wise in the field.
2. YOKE TYPE
It is a horse shoe magnet made byelectrically energising it or by the use of a
permanent magnet.
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YOKE TECHNIQUE
i. Direct Current Yoke
ii. Alternate Current Yokeiii. Permanent Magnet Yoke
MPT METHODS
1. Based on Magnetic Particle type
a) Visibleb) Fluorescent
2. Based on Magnetic Particle Application
a) Dry
b) Wet
CHECKING OF YOKE
LIFTING POWER
i. DC Type & Permanent Min.Weight - 40 Lbs.
( At Max. Pole Spacing )
ii. AC type Min.Weight - 10 Lbs.(At Max. Pole Spacing )
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Eight low carbon steel pie sections, Furnace brazed together
1 in. Non Ferrous handle
of any convenient length
Artificial flaw (All segment interfaces) 1/32 in. max.
Brazed weld or mechanically attach Non-ferrous trunnions
Copper Plate 0.010 in. 0.010 in. thick
1/8 in.
ASTM Magnetic Particle Field Indicator
MAGNET PARTICLE STANDARDS ASME SECTION V (ARTICLE 25)
SE-709Standard practice for Magnetic Particle
Examination
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PRINCIPLE
Uses ultrasound wave to penetrate material, indicating
discontinuities on Oscilloscope Screen.
APPLICATIONS
Used on metals, ceramics, plastics, etc. to detectsurface and internal discontinuities. When automated,
indications are recorded on paper, it provides apermanent record. Also used for measuring thickness.
LIMITATIONS
Moderately high initial cost. Interpretation of test
results requires highly trained personnel.
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TYPE OF ULTRASONIC WAVES
1. LONGITUDINAL (OR COMPRESSION) WAVES
2. TRANSVERSE (OR SHEAR) WAVES
3. SURFACE WAVE
4. PLATE ( LAM B ) WAVES
PROPERTIES OF ULTRASONIC BEAM
1. Travel in a straight line.
2. Reflect and refract from the boundary of different
acoustic media.
3. .Attenuate while passing through a media.
4. The extent of attenuation depends on
- Absorption ( dependent on grain size )
- Diffraction or spreading (dependent on wavelength and probe diameter )
5. Velocity in a media depends on the density &elastic constants. The values for differentmedia's are given in the following chart.
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TECHNIQUES
1. Contact Testing2. Immersion testing
DATA PRESENTATION
1. `A' SCAN METHOD
This method is commonly known as Pulse EchMethod. Time versus Amplitude display showon Cathode Ray Tube.
2. `B' SCAN METHOD
This method displays cross sectionalview.
3. `C' SCAN METHOD
This method displaysplanview and comparablto radiographic image.
NOTE:-More than 90 % of total Ultrasonic Examinations arcarried out by "A" Scan Method.
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METHODS
.PULSE-ECHO
.THROUGH TRANSMISSION
.RESONANCE
TYPES OF PROBES
I. SINGLE CRYSTAL NORMAL BEAM PROBE.
II. SINGLE CRYSTAL ANGLE BEAM PROBE.
III. TWIN CRYSTAL PROBES.
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"DAC" CURVE
Same size of defect or reference reflector atdifferent distance/depth give's different signalamplitude because of attenuation of ultrasonicbeam in medium. As such defect Amplitudecorrection Curve has to be drawn as shown in fig.
T/2
T/2
SDH 2.4 mm
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ULTRASONIC STANDARD
SA - 388Recommended practice for Ultrasonic testing aninspection of heavy steel forging.
SA - 435Standard specification for straight beam ultrasonexamination of steel plates.
SA - 577Standard specification of ultrasonic angle bea
examination of steel plates.
SA - 578Standards specification for straight beam ultrasonexamination of plain and clad steel plates of speciapplication.
SA - 609Standard specification for longitudinal ultrasoninspection of carbon and low alloy steel casting.
SA - 745Standard practice for Ultrasonic examination of austenitsteel forging.
SE - 213Standard practice for ultrasonic inspection of metal pipand tubes.
SE - 797Standard practice for thickness measurement by manu
contact ultrasonic method.
Recommended