Non destructive testing Introduction

Introduction to Nondestructive Testing

INTRODUCTION TO NDT TRAINING

• SNT –TC-1A – CURRENT EDITION

• ( REF TRAINING STANDARD)

• ASNT – AMERICAN SOCIETY FOR NON DESTRUCTIVE TESTING

• TC – TECHNICAL COUNCIL

• 1A – VERSION OF DOCUMENT

• CURRENT EDITION ( 2001 ) TILL NOW

NDT METHODS W.R.T CERTIFICATION

12 NDT METHODS

• RADIOGRAPHY TESTING

• ULTRASONIC TESTING

• MAGNETIC PARTICLE TESTING

• PENETRANT TESTING

• VISUAL TESTING

• ELECTROMAGNETIC TESTING

NDT METHODS W.R.T CERTIFICATION

12 NDT METHODS

• ACOUSTIC EMISSIONS

• VIBRATION MONITOR ANALYSIS

• THERMAL INFRARED TESTING

• LEAK TESTING

• LASER TESTING

• NEUTRON RADIOGRAPHY

LIMITED CERTIFICATION

RADIOGRAPHY TESTING

• FILM RADIOGRAPHY

• XEROX RADIOGRAPHY

• MICROFOCUS RADIOGRAPHY

• STEREO RADIOGRAPHY

• X-RAY CRAWLER

• REAL TIME RADIOGRAPHY


ULTRASONIC TESTING

• PULSE ECHO TECHNIQUE

• IMMERSION TECHNIQUE

• THROUGH TRANSMISSION TECHNIQUE


MAGNETIC PARTICLE TESTING

CIRCULAR MAGNETIZATION

• HEAD SHOT TECHNIQUE

• PROD TECHNIQUE

• CENTRAL CONDUCTOR TECHNIQUE

LONGITUDINAL MAGNETIZATION

• YOKE TECHNIQUE

• COIL TECHNIQUE


PENETRANT TESTING

• WATER WASHABLE

• SOLVENT REMOVABLE

• POST EMULSIFICATION

Note : classified based on removal of excess penetrant


VISUAL TESTING

• BOROSCOPE

• FIBEROSCOPE

• TEM/SEM

• HOLOGRAPHY


EDDY CURRENT TESTING

• IMPEDANCE ANALYSIS – METER DISPLAY

• PHASE ANALYSIS – CRT DISPLAY

• MODULATION ANALYSIS – STRIP CHART RECORDER

FUNCTIONS & LEVELS OF QUALIFICATION

• LEVEL- I

1. FUNCTION AS A NDT OPERATOR/TECHNICIAN

2. PERFORM SPECIFIC CALIBRATIONS

3. CARRY OUT TESTING IN PRESENCE OF LEVEL-II/III

4. NOT AUTHORIZED TO SIGN THE INTERPRETATION SHEET

FUNCTIONS & LEVELS OF QUALIFICATIONS

• LEVEL-II

1. PREPARED WRITTEN PROCEDURES

2. FUNCTION AS NDT INSPECTOR

3. PERFORM SPECIFIC CALIBRATIONS & VERIFY THE RESULTS

4. AUTHORIZED TO SIGN THE INTERPRETATION SHEET

FUNCTIONS & LEVELS OF QUALIFICATIONS

• LEVEL-III

1. APPROVE THE WRITTEN PROCEDURES

2. ESTABLISH THE TECHNIQUES

3. TRAIN LEVEL –I /II

4. OVER ALL INCHARGE OF NDT JOBS

MODE OF EXAMINATION

LEVEL-I/IIGENERAL – 40 QUESTIONS – 1 HR – 100 MARKS

( CLOSED BOOK ) – PASSING PERCENTAGE -70%

SPECIFIC – 20 QUESTIONS – 1 HR – 100 MARKS

( OPEN BOOK ) – PASSING PERCENTAGE – 70%

PRACTICAL – 10 QUESTIONS – 2 HRS – 100 MARKS

( 10 SAMPLES ) – PASSING PERCENTAGE – 70%

MODE OF EXAMINATION

LEVEL-III

BASIC ( MANDATORY PAPER ) -135 QUE- 4 HRS

METHOD ( ANY OF 12 METHODS )

ALL 135 QUE – 4 HRS

ALL 80 QUE – 2 HRS

TIME PERIOD OF ISSUING CERTIFICATION

• MAXIMUM TIME PERIOD : SIX MONTHS FROM DATE OF PASSING EXAM

( LEVEL-I/II) – FOUR MONTHS – SIX MONTHS

NOTE : RE-EXAM SHALL BE CONDUCTED AFTER 60 DAYS IF CANDIDATE FAILED TO MEET PASSING REQUIREMENTS

ASME SECTIONS

• SECTION-1 – RULES FOR CONSTRUCTION OF POWER BOILERS

• SECTION-2 – MATERIALS

• PART A – FERROUS MATERIAL

• PART B – NON-FERROUS MATERIAL

• PART C – SPECIFICATION OF WELDING RODS , ELECTRODES & FILLER METALS

• PART D – PROPERTIES

• SECTION-3 – RULES FOR CONSTRUCTION OF NUCLEAR POWER PLANT COMPONENTS

• SECTION-4 – RULES FOR CONSTRUCTION OF HEATING BOILERS

ASME SECTIONS

• SECTION -5 – NON-DESTRUCTIVE EVALUATION

• ARTICLE-2 – RADIOGRAPHY TESTING

• ARTICLE-5- ULTRASONIC TESTING

• ARTICLE-6- PENETRANT TESTING

• ARTICLE-7- MAGNETIC PARTICLE TESTING

• ARTICLE-8- EDDY CURRENT TESTING

• ARTICLE-9-VISUAL TESTING

• ARTICLE-10 – LEAK TESTING

ASME SECTIONS

• SECTION-6 – CARE & OPERATION OF POWER BOILERS

• SECTION-7- CARE & OPERATION OF HEATING BOILERS

• SECTION-8 – BOILERS & PRESSURE VESSEL CODE

• SECTION-9 – WELDING & BRAZING QUALIFICATION

• SECTION-10- RULES FOR CONSTRUCTION OF FRP VESSELS

• SECTION-11 – RULES FOR INSERVICE INSPECTION OF NUCLEAR POWER PLANT COMPONENTS

• SECTION-12- RULES FOR TRANSPORT OF STORAGE TANKS

CODES & PURPOSE

• API-1104 – CROSS COUNTRY WELDING PIPELINE

• API-650- ABOVE GROUND WELDED STORAGE TANKS

• ASMEB31.3- PROCESS PIPING

• AWS D1.1 – STRUCTURAL WELDING OF STEEL

CODES & PURPOSE• ASME-SEC-VIII- BOILERS & PRESSURE VESSELS CODE

• ASME SEC-IX – WELDING & BRAZING QUALIFICATIONS

• ASME SEC-III – RULES FOR CONSTRUCTION OF NUCLEAR POWER PLANT COMPONENTS

• ASME SEC-II (PART-C ) – SPECIFICATION OF WELDING RODS , ELECTRODES & FILLER METALS

Selection of NDT METHODS

• TYPE OF MATERIAL

( Whether it is ferrous/non-ferrous/ conductivity material )

• TYPE OF MANUFACTURING PROCESS

( Whether it is casting, forging, welding , rolling etc )

• TYPE & ORIENTATION OF DISCONTINUITY

( Whether it is surface / near surface/ sub surface)

• Cost

VISUAL TESTING

• ONLY FOR SURFACE DISCONTINUTIES

• FOR ANY TYPE OF MATERIALS

• FOR ANY TYPE OF MANUFACTURING PROCESS

• TEMPERATURE IS NOT A CONSTRAINT

• BASIC TESTING

• ADVANCE EQUIPMENTS ARE MORE EXPENSIVE.

PENETRANT TESTING

• ONLY FOR DISCONTINUTIES WHICH ARE OPEN TO SURFACE

• FOR NON-POROUS MATERIALS• TEMPERATURE ( 10 DEG CENTIGRADE TO

50 DEG CENTIGRADE ) . • HIGH TEMPERATURE PENETRANTS ( 200

DEG CENTIGRADE) SPECIAL TYPE OF MATERIALS AVAILIABLE.

• LESS EXPENSIVE & BETTER FOR FIELD USE• PORTABLE CANS ARE AVAILIABLE• TIME CONSUMING

MAGNETIC PARTICLE TESTING

• ONLY FOR FERROMAGNETIC MATERIALS

• FOR SURFACE & NEAR SURFACE DISCONTINUITIES

• IMMEDIATE INDICATION

• TEMPERATURE UPTO 300 DEG CENTIGRADE BY USING DRY POWDERS.

• LESS EXPENSIVE & TIME SAVING

• TESTING POSSIBLE EVEN FOREIGN MATERIAL EMBEDDED OVER THE SURFACE.

RADIOGRAPHY TESTING

• FOR SURFACE/NEAR SURFACE/ SUBSURFACE

• FOR ANY TYPE OF MATERIAL

• SAFETY RULES & REGULATIONS SHALL BE FOLLOWED

• MORE EXPENSIVE & TIME CONSUMING

• RADIATION IS DANGEROUS IF SAFETY IS NOT FOLLOWED

• LOCATION OF DISCONTINUITY

• DIRECT INDICATION

ULTRASONIC TESTING

• FOR ANY TYPE OF DISCONTINUITY

• FOR ANY TYPE OF MATERIAL EXCEPT COARSE GRAINED MATERIAL ( EX:SS, CU)

• DEPTH OF DISCONTINUITY

• IMMEDIATE SIGNAL

• TESTING UNDER NORMAL TEMPERATURE

• SKILL IS REQUIRED

• INDIRECT INDICATION

Outline

• Introduction to NDT• Overview of Six Most

Common NDT Methods

• Selected Applications

The use of noninvasive techniques to determine the integrity of a material, component or structure

or quantitatively measuresome characteristic ofan object.

i.e. Inspect or measure without doing harm.

Definition of NDT

Methods of NDT

Visual

Liquid Penetrant

Magnetic Particle

Eddy Current

Ultrasonic

Radiography

Microwave

Acoustic Emission

Thermography

Laser Interferometry

Replication

Flux Leakage

Acoustic Microscopy

Magnetic Measurements

Tap Testing

What are Some Uses of NDE Methods?

• Flaw Detection and Evaluation

• Leak Detection

• Location Determination

• Dimensional Measurements

• Structure and Microstructure Characterization

• Estimation of Mechanical and Physical Properties

• Stress (Strain) and Dynamic Response Measurements

• Material Sorting and Chemical Composition Determination

Fluorescent penetrant indication

When are NDE Methods Used?

– To assist in product development

– To screen or sort incoming materials

– To monitor, improve or control manufacturing processes

– To verify proper processing such as heat treating

– To verify proper assembly

– To inspect for in-service damage

There are NDE application at almost any stage in the production or life cycle of a component.

There are NDE application at almost any stage in the production or life cycle of a component.

Six Most Common NDT Methods

• Visual• Liquid Penetrant • Magnetic • Ultrasonic• Eddy Current• Radiography

Most basic and common inspection method.

Tools include fiberscopes, borescopes, magnifying glasses and mirrors.

Robotic crawlers permit observation in hazardous or tight areas, such as air ducts, reactors, pipelines.

Portable video inspection unit with zoom allows

inspection of large tanks and vessels, railroad tank

cars, sewer lines.

Visual Inspection

• A liquid with high surface wetting characteristics is applied to the surface of the part and allowed time to seep into surface breaking defects.

• The excess liquid is removed from the surface of the part.

• A developer (powder) is applied to pull the trapped penetrant out the defect and spread it on the surface where it can be seen.

• Visual inspection is the final step in the process. The penetrant used is often loaded with a fluorescent dye and the inspection is done under UV light to increase test sensitivity.

Liquid Penetrant Inspection

Magnetic Particle Inspection

The part is magnetized. Finely milled iron particles coated with a dye pigment are then applied to the specimen. These particles are attracted to magnetic flux leakage fields and will cluster to form an indication directly over the discontinuity. This indication can be visually detected under proper lighting conditions.

Magnetic Particle Crack Indications

RadiographyThe radiation used in radiography testing is a higher energy (shorter wavelength) version of the electromagnetic waves that we see as visible light. The radiation can come from an X-ray generator or a radioactive source.

High Electrical Potential

Electrons

-+

X-ray Generator or Radioactive Source Creates

Radiation

Exposure Recording Device

Radiation Penetrate the Sample

Film Radiography

Top view of developed film

X-ray film

The part is placed between the radiation source and a piece of film. The part will stop some of the radiation. Thicker and more dense area will stop more of the radiation.

= more exposure

= less exposure

The film darkness (density) will vary with the amount of radiation reaching the film through the test object.

Radiographic Images

Conductive material

CoilCoil's magnetic field

Eddy currents

Eddy current's magnetic field

Eddy Current Testing

Eddy Current TestingEddy current testing is particularly well suited for detecting surface cracks but can also be used to make electrical conductivity and coating thickness measurements. Here a small surface probe is scanned over the part surface in an attempt to detect a crack.

Eddy current testing is particularly well suited for detecting surface cracks but can also be used to make electrical conductivity and coating thickness measurements. Here a small surface probe is scanned over the part surface in an attempt to detect a crack.

High frequency sound waves are introduced into a material and they are reflected back from surfaces or flaws.

Reflected sound energy is displayed versus time, and inspector can visualize a cross section of the specimen showing the depth of features that reflect sound.

f

plate

crack

0 2 4 6 8 10

initial pulse

crack echo

back surface echo

Oscilloscope, or flaw detector screen

Ultrasonic Inspection (Pulse-Echo)

Ultrasonic Imaging

Gray scale image produced using the sound reflected from the front surface of the coin

Gray scale image produced using the sound reflected from the back surface of the coin (inspected from “heads” side)

High resolution images can be produced by plotting signal strength or time-of-flight using a computer-controlled scanning system.

Common Application of NDT

• Inspection of Raw Products

• Inspection Following Secondary Processing

• In-Services Damage Inspection

Inspection of Raw Products

• Forgings,• Castings,• Extrusions,• etc.

• Machining• Welding• Grinding• Heat treating• Plating• etc.

Inspection Following Secondary Processing

• Cracking

• Corrosion

• Erosion/Wear

• Heat Damage

• etc.

Inspection For In-Service Damage

Power Plant Inspection

Probe

Signals produced by

various amounts of corrosion

thinning.

Periodically, power plants are shutdown for inspection. Inspectors feed eddy current probes into heat exchanger tubes to check for corrosion damage.

Pipe with damage

Wire Rope InspectionElectromagnetic devices and visual inspections are used to find broken wires and other damage to the wire rope that is used in chairlifts, cranes and other lifting devices.

Storage Tank Inspection

Robotic crawlers use ultrasound to inspect the walls of large above ground tanks for signs of thinning due to corrosion.

Cameras on long articulating arms are used to inspect underground storage tanks for damage.

Aircraft Inspection• Nondestructive testing is used

extensively during the manufacturing of aircraft.

• NDT is also used to find cracks and corrosion damage during operation of the aircraft.

• A fatigue crack that started at the site of a lightning strike is shown below.

Jet Engine Inspection• Aircraft engines are overhauled

after being in service for a period of time.

• They are completely disassembled, cleaned, inspected and then reassembled.

• Fluorescent penetrant inspection is used to check many of the parts for cracking.

Sioux City, Iowa, July 19, 1989A defect that went undetected in an engine disk was responsible for the crash of United Flight 232.

Crash of United Flight 232

Pressure Vessel InspectionThe failure of a pressure vessel can result in the rapid release of a large amount of energy. To protect against this dangerous event, the tanks are inspected using radiography and ultrasonic testing.

Rail Inspection

Special cars are used to inspect thousands of miles of rail to find cracks that could lead to a derailment.

Bridge Inspection• The US has 578,000

highway bridges.

• Corrosion, cracking and other damage can all affect a bridge’s performance.

• The collapse of the Silver Bridge in 1967 resulted in loss of 47 lives.

• Bridges get a visual inspection about every 2 years.

• Some bridges are fitted with acoustic emission sensors that “listen” for sounds of cracks growing.

NDT is used to inspect pipelines to prevent leaks that could damage the environment. Visual inspection, radiography and electromagnetic testing are some of the NDT methods used.

Remote visual inspection using a robotic crawler.

Radiography of weld joints.

Magnetic flux leakage inspection. This device, known as a pig, is placed in the pipeline and collects data on the condition of the pipe as it is pushed along by whatever is being transported.

Pipeline Inspection

Special MeasurementsBoeing employees in Philadelphia were given the privilege of evaluating the Liberty Bell for damage using NDT techniques. Eddy current methods were used to measure the electrical conductivity of the Bell's bronze casing at a various points to evaluate its uniformity.

For More Information on NDT

The Collaboration for NDT Education

www.ndt-ed.org

The American Society for Nondestructive

Testing

www.asnt.org

Non destructive testing Introduction

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