Presented by:

Name: YOUNES Last name: SALARI LEVEL II ASNT : VT & PT & MT & RTI Education: Mechanical (welding Engineering) university mashhad –Iran & Cell phone:

TESTING Destructive Testing  Bend Test  Tensile Test  Impact Test  Hardness Test  Chemical Analysis  Fatigue Test  Macro Test Nondestructive Testing  Radiographic Testing  Ultrasonic Testing  Magnetic Particle Testing  Liquid Penetrant Testing  Visual Testing  Acoustic Emission  Leak Testing  Eddy current Testing  Neutron Radiography  Thermal Emission  Laser Testing  Vibrating Analysis

APPROACH NDT applicable methods for Engineering Industry  Principle  Application  Selection

Inspection Standards & Acceptance Limits  Codes / Standards in NDT  Design Code governing Requirements (e.g. ASME Sec. VIII Div 1 & 2, Sec. III)  Procedure Codes giving Techniques Details (e.g. ASME Sec V)  Discontinuity / Defect / Acceptance Standards  Interpretation X Evaluation

Importance of Training Success of NDT depends on  Operator’s skill  Operator’s knowledge  Operator’s training  Selection of proper technique / machine  Employment of Qualified manpower Article 1 : certified personal * calibrated equipment * approved procedure Hence Qualification & Certification is a MUST!

Importance of Personnel Qualification & Certification in NDT  Why personal qualification?  What are the standards?  SNT-TC-1A scheme  ASNT Certification  Responsibilities of Level I / Level II / Level III

NDT METHODS ( surface discontinuities)  Visual Testing (VT)  Liquid Penetrant Testing (PT)  Magnetic Particle Testing (MT)  Eddy Current Testing (ET)  Leak Testing (LT)

Visual Testing Principle: Use of eye & instruments Equipments Need: Magnifiers, color enhancement, projectors, other measurable instruments i.e. rulers, micrometers, optical comparators, light source Application: Welds which have discontinuities on surface Advantages: Economical, expedient, requires relatively little training & relatively little equipment for many applications Limitations: Limited to external or surface conditions only. Limited to visual acuity of inspector Use: Quantity, size, shape surface finish, reflectivity, colors, fit, functional characteristics, presence of surface discontinuities

Fundamental of VT Vision Light Material Environmental Factors Visual Perception Direct and indirect Methods

Liquid Penetrant Principles: Capillary Action-detects surface discontinuities only

Liquid Penetrant

Equipment need : Fluorescent or visible dye penetrant developers cleaners (solvents, emulsifiers, etc) Suitable cleaning agent, Ultraviolet light source if fluorescent if dye is used. Application : Weld discontinuities open to surface, i.e. cracks, porosity.

Liquid Penetrant Advantages: Portable, relatively inexpensive equipment. Expedient inspection result. Result are easy interpreted requires no electrical energy except for light source. Limitation: Surface films such as coating, scale smeared metal mask or hide rejectable defects. Seepage from weld porosity at the surface can also mask indications. Part must be cleaned before and after inspection.

Liquid Penetrant

Magnetic Particle Principle: Magnetic flux leakage detect discontinuities.

Magnetic Particle Equipment: Prods, yokes, coils suitable for inducing magnetism tnto the weld. Power source (electrical) Magnetic powders Some application require specal facilities and ultraviolet light.

Magnetic Particle

Application: Most weld discontinuities to the surface, some large voids slightly subsurface. Most suitable for cracks.

Magnetic Particle Advantages: Relatively economical and expedient, Inspection equipment is considered portable. Unlike dye penetrants, magnetic Particle can detect some discontinuities slightly below the surface can be used for higher temperatures. Limitations: Applicable only to ferromagnetic material. Parts must be cleaned before and after inspection. Thick coatings may mask rejectable discontinuities. Some applications require parts to be demagnetized after inspection. Magnetic particle inspection requires use of electrical energy for most applications.

MT For Magnetic Materials For surface and sub-surface detect detection Quick & Fast Can detect inclusions & foreign material entrapment Based on principle of attraction of magnetic particles to flux leakage Easy post cleaning Best method for detecting stress corrosion cracks & fatigue cracks PT For all materials Only for surface detection Slower process Cannot detect such defects Based on principles of capilary action Subsequent cleaning (Post cleaning) trouble

Conductive material Coil Coil's magnetic field Eddy currents Eddy current's magnetic field Eddy Current Testing Principle: Electromagnetic Induction

Eddy Current Testing Equipment needs: An instrument capable of inducing electromagnetic fields within a weld and sensing the resulting electrical currents (eddy) so induced with a suitable probe or detector, calibration standards. Applications: Weld discontinuities open to the surface (i.e. cracks, porosity, and incomplete fusion) as well as some subsurface discontinuities. Alloy content, heat treatment variations. Advantages: Equipment used with surface probes is generally light weight and portable. Painted or coated welds can be inspected. Can be partially or completely automated for high speed relatively inexpensive test. Limitations: Relatively shallow depth of inspection. Many material and test variables can affect the test signal.

Leak Testing Principle: Leakage of fluid detected by different detectors. Equipment needs: Bubble test, Pressure change measurement test Halogen Diode leak detection, Mass Spectrometer Leak detection (MSLDT) Applications: Leakage of storage tanks, Leak tightness of systems, very fine leak testing by Helium leak detector for electronic components and nuclear components. Advantages: Very sensitive, Used for checking vacuum tightness. Limitations: Limited to thro and thro leak only. Cleaning and drying is mandatory. Expensive in case of MSLDT.

 Radiographic Testing  Gamma  X-rays  Ultrasonic Testing

RADIOGRAPHY (GAMMA) Principle: Differential absorption of radiation by the object gives density variation in the film Equipment needs: Gamma ray sources, gamma ray camera projectors, film holders, film, lead screens, film processing equipment, film viewers, exposure facilities, radiation monitoring equipment

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.

Principles of RT Sensitivity: The measure of the capability to detect small defects. Sensitivity in a radiograph is a function of the “Contrast” and the “Definition” of the radiograph. Density: Degree of film blackening.

Definition Definition is the line of demarcation between areas of different densities. If the image is clear and sharp the radiograph is said to have good definition as shown below. Film “ B ” shows better definition than film “ A ”. AB Principles of RT

RADIOGRAPHY (GAMMA) Application: welds which have voluminous discontinuities such as Porosity, incomplete joint penetration, corrosion,etc,Lamellar type discontinuities such as cracks and incomplete fusion can be detected with a lesser degree of reliability. May also be used in certain applications to evaluate dimensional requirement such as fit-up, root Conditions, and wall thickness.

RADIOGRAPHY (GAMMA) Advantages: Generally not restricted by type of material or grain structure. Surface and subsurface inspection capability. Radiographic images aid in characterizing discontinuities Provides a permanent record for future review. Limitations: planar discontinuities must be favorably aligned with radiation beam to be reliably detected; radiation poses a potential hazard to personnel. Cost radiographic equipment, facilities, safety programs, and related licensing is relatively high. A relatively long time between exposure process and availability of results. Accessibility to both sides of the weld required.

RADIOGRAPHY (X-RAYS) Principle: Differential absorption of radiation by the object gives density variation in the Film High Electrical Potential Electrons - + X-ray Generator or Radioactive Source Creates Radiation Exposure Recording Device Radiation Penetrate the Sample

RADIOGRAPHY (X-RAYS) Equipments needs: X-ray sources (machines), electrical power source, same general equipment as used with gamma sources (above (

RADIOGRAPHY (X-RAYS) Advantages: Adjustable energy levels. Generally produces higher quality radiographs than gamma sources. Also same advantages as above. Limitations: High initial cost of X-ray equipment. Not generally considered portable. Also, same limitations as above.

Principle: Reflection of sound beam by a flaw gives signal on the oscilloscope. 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 initial pulse crack echo back surface echo Oscilloscope, or flaw detector screen Ultrasonic Inspection (Pulse-Echo)

Ultrasonic Testing Equipment needs: Pulse-echo Instrument capable of exciting a piezoelectric material and generating ultrasonic energy within a weld, and a suitable cathode ray tube scope capable of displaying the magnitudes of received sound energy. Calibration standards, liquid couplant. Application: Most weld discontinuities including cracks, slag and incomplete fusion. Can also De used to verify weld thickness. Advantages: Most sensitive to planar type discontinuities. Test results known immediately. Portable. Most ultrasonic flaw detectors do not require an electrical power outlet. High penetration capability. Limitations: Surface condition must be suitable for coupling of transducer. Couplant )liquid) required. Small thin welds may be difficult inspect. Reference standards are required. Requires a relatively skilled operator or inspector.

UT Techniques Two basic techniques are used in locating and evaluating angular flaws 1. Contact testing utilizes an ''angle beam'' transducer with plastic wedge to change the direction of wave propagation. 2. Immersion testing uses water as a couplant, tilting the transducer to achieve the necessary directionality. The shape or surface condition of a discontinuity influences the indication on the CRT. A discontinuity having a rough surface will tend to scatter the reflection as compared to a smooth flaw. Nonmetallic inclusions are typically rough and would scatter the sound more than a crack-like discontinuity.

Angle Beam Probes

UT For internal & surface defects More suitable for planer (two dimensional defects Accessibility from one side is sufficient Size and location of the defect can be judged quite accurately Better sensitivity & resolution Possible to test higher thickness upto 5 meters Operator skill is important No safety problem Faster results RT Only for internal defects Possible to detect only voluminous (3D) defects Accessibility from both sides is must. It is difficult to judge the size & location of defects Poor sensitivity ~ 2% for gamma rays ~ 1% for X rays Thickness limitations --- Safety precautions are mandatory Slower results in film radiography. On line radiography very costly

Selection of a particular NDT method Advantages/Limitations of methods Acceptance standard Cost Manufacturing technology Type of discontinuities Physical Condition of the job Need of qualified engineer/technician

NDT Symbols Standard Location of Elements

NDT Symbols Arrow Side Other Side

NDT Symbols Both Side No Side Significance

NDT Symbols Length of Weld to be Tested Location of Weld to be Tested

NDT Symbols Percentage of Weld Length to be Tested Number of Tests to be Performed on a Joint or at Random Location on the Welds

NDT Symbols Test All Around

NDT Symbols Orientation of Radiation Source

NDT Symbols Combination of Welding and Testing Symbols