Q: What is the most commonly used material for Gasket.
Ans: Compressed Asbestos Fibre.
Q: Which type of gasket is recommended for high temperature & high pressure application.
Ans: Spiral wound Metallic Gasket.
Q: What are the criteria for selection of MOC of Spiral Wound Metallic Gasket winding material.
Ans: The selection of material of construction for Gasket winding depends upon:-
A) The corrosive nature and concentration of fluid being carried.
B) The operating temeperature of the fluid.
C) The relative cost of alternative winding material.
Q: What are the most common materials used for spiral wound metallic gasket winding.
Ans: The most commonly used material for spiral wound metallic gasket winding is:-
A) Austenitic stainless steel 304 with asbetos filler.
B) Austenitic stainless steel 316 with asbetos filler.
C) Austenitic stainless steel 321 with asbetos filler.
Q: Which material is used as filler material for spiral wound gasket in case of high temperature services.
Ans: For very high temperature services, graphite filler is used.
Q: What is centering ring in connection to spiral wound gasket.
Ans: Spiral wound gaskets are provided with carbon steel external ring called centering ring.
Q: What will be the AARH finish on flange face for using spiral wound gasket.
Ans: 125-250 AARH finish.
Q: Up to what temperature the carbon steel materials shall be used.
Ans: Carbon steel materials shall be used for temperature up to 425 C.
Q: Which material is used for temperature above 426 C.
Ans: Alloy steel materials shall be used for temperature above 426 C.
Q: Which type of material is used for corrosive fluid.
Ans: Stainless steel materials shall be used for corrosive fluid.
Q: Which type of piping materials are used for drinking water, instrument air etc.
Ans: Galavanized steel materials shall be used for drinking water, instrument air and NI lines (LP).
Q: What is the difference between Pipe and Tube.
Ans: Pipe is identified by NB and thickness is defined by Schedule whereas Tube is identified by OD & its thickness as BWG (Birmingham wire gauge or 1/100 inch).
Created by: Mihir Thakur
Checked by: Sanjay Singh
Wednesday, October 20, 2010
Tuesday, October 19, 2010
How can flanges be classified based on face finish
Flanges are classified based on face finish as:-
(A): Smooth Finish
(B): Serrated Finish
Where the Smooth finish flange & Serrated finish flange finds its use.
Answer: The Smooth Finish flange is provided when metallic gasket is provided and serrated finish flange is provided when non-metallic gasket is provided.
What are the Types of serrated finish provided on flange face.
A. Concentric
B. Spiral (Phonographic)
How the Serration on flanges is specified.
Answer: The serration on flanges is specified by the number, which is the Arithmetic Average Rough Height (AARH)
(A): Smooth Finish
(B): Serrated Finish
Where the Smooth finish flange & Serrated finish flange finds its use.
Answer: The Smooth Finish flange is provided when metallic gasket is provided and serrated finish flange is provided when non-metallic gasket is provided.
What are the Types of serrated finish provided on flange face.
A. Concentric
B. Spiral (Phonographic)
How the Serration on flanges is specified.
Answer: The serration on flanges is specified by the number, which is the Arithmetic Average Rough Height (AARH)
How can flanges be classified based on facing
Flanges are classified based on facing.
Flat Face (FF)
Raised Face(R/F)
Tongue and Groove (T/G)
Male and Female (M/F)
Ring Type Joint (RTJ)
Flat Face (FF)
Raised Face(R/F)
Tongue and Groove (T/G)
Male and Female (M/F)
Ring Type Joint (RTJ)
How can flanges be classified based on Pressure Temperature Ratings
Flanges are classified based on pressure temperature ratings as:-
A. 150#
B. 300#
C. 400#
D. 600#
E. 900#
F. 1500#
G. 2500#
Pressure temperature rating carts in the standard ASME 16.5 specify the non-shock working gauge pressure to which the flange can be subjected to at a particular temperature.
A. 150#
B. 300#
C. 400#
D. 600#
E. 900#
F. 1500#
G. 2500#
Pressure temperature rating carts in the standard ASME 16.5 specify the non-shock working gauge pressure to which the flange can be subjected to at a particular temperature.
Questionaire of Pipe Fitting
Slip-on: The Slip-on flanges are attached by welding inside as well as outside. These flanges are of forged construction.
Socket Weld: The Socket weld flanges are welded on one side only. These are used for small bore lines only.
Screwed: The Screwed-on flanges are used on pipe lines where welding cannot be carried out.
Lap Joint: The Lap Joint flanges are used with slub ends. The slub ends are welded with pipes & flanges are kept loose over the same.
Welding Neck: The welding neck flanges are attached by Butt Welding to the pipe. These are used mainlyfor critical services where the weld joints need Radiographic Inspection.
Blind: The blind flanges are used to close the ends which need to be reopened.
Reducing: The Reducing flanges are used to connect between larger and smaller sizez without using a reducer. In case of reducing flanges, the thickness of flange should be that of the higher diameter.
Integral: Integral flanges are those, which are cast along with the piping component or equipment.
Socket Weld: The Socket weld flanges are welded on one side only. These are used for small bore lines only.
Screwed: The Screwed-on flanges are used on pipe lines where welding cannot be carried out.
Lap Joint: The Lap Joint flanges are used with slub ends. The slub ends are welded with pipes & flanges are kept loose over the same.
Welding Neck: The welding neck flanges are attached by Butt Welding to the pipe. These are used mainlyfor critical services where the weld joints need Radiographic Inspection.
Blind: The blind flanges are used to close the ends which need to be reopened.
Reducing: The Reducing flanges are used to connect between larger and smaller sizez without using a reducer. In case of reducing flanges, the thickness of flange should be that of the higher diameter.
Integral: Integral flanges are those, which are cast along with the piping component or equipment.
NDT , Welding , Piping Questionaire
What is the ASME code followed for design of piping systems in Process Piping ( Refineries & Chemical Industries.
B 31. 3 is the right Answer.
Which American Institute standard does piping engineer refer.
1) API
2) ASTM
3) ASME
4) ANSI
5) AWWA
6) AWS
7) AISI
What is the different ASME 31 code for pressure piping.
ASME B 31.1: Power Piping
B 31. 2: Fuel Gas Piping
B 31.3: Process Piping
B 31.4: Pipeline Transportation system for liquid hydrocarbon & other liquid.
B 31.5: Refrigeration Piping
B 31.8: Gas transmission & distribution piping system
B 31.9 Building services piping
B. 31.11 Slurry transportation piping system.
What are the different sections of ASME code. Where these sections are reffered.
ASME Section- 1: Rules for construction of Power Boiler
Section – 2: Materials:
A) Ferrous Materials
B) Non-Ferrous Materials
C) Specification for electrodes & filler wire
D) Properties
ASME Section – 4: Rules for construction of Heating Boiler
ASME Section – 5: Non- Destructive Examination
ASME Section -6: Recommended rules for care & operation of heating boiler
ASME Section-7: Recommended guidelines for care of Power Boiler
ASME Section-8: Rules for construction of pressure vessels. (Division I-II)
ASME Section -9: Welding & Brazing Qualification
B 31. 3 is the right Answer.
Which American Institute standard does piping engineer refer.
1) API
2) ASTM
3) ASME
4) ANSI
5) AWWA
6) AWS
7) AISI
What is the different ASME 31 code for pressure piping.
ASME B 31.1: Power Piping
B 31. 2: Fuel Gas Piping
B 31.3: Process Piping
B 31.4: Pipeline Transportation system for liquid hydrocarbon & other liquid.
B 31.5: Refrigeration Piping
B 31.8: Gas transmission & distribution piping system
B 31.9 Building services piping
B. 31.11 Slurry transportation piping system.
What are the different sections of ASME code. Where these sections are reffered.
ASME Section- 1: Rules for construction of Power Boiler
Section – 2: Materials:
A) Ferrous Materials
B) Non-Ferrous Materials
C) Specification for electrodes & filler wire
D) Properties
ASME Section – 4: Rules for construction of Heating Boiler
ASME Section – 5: Non- Destructive Examination
ASME Section -6: Recommended rules for care & operation of heating boiler
ASME Section-7: Recommended guidelines for care of Power Boiler
ASME Section-8: Rules for construction of pressure vessels. (Division I-II)
ASME Section -9: Welding & Brazing Qualification
What Kind of NDT techniques are used to ensure the safety of the air plane
NDT methods allow inspectors to inspect areas of the plane that would otherwise be uninspectable without disassembling structure to gain access to the internal areas. NDT methods also allow inspectors to detect damage that is too small to be detected by visual means. Eddy current and ultrasonic inspection methods are used extensively to locate tiny cracks that would otherwise be undetectable. These techniques are also used to measure the thickness of the aircraft skin from the outside and detect metal thining from corrosion on the inside surface of the skin. X-ray techniques are used to find defects buried deep within the structure and to locate areas were water has penetrated into certain structure. Obviously, this task requires trained professionals who are capable of performing a variety of different NDT Techniques to get a complete and accurate status of the airplane.
There is no question that the success of the air plane industry is dependent on NDT. Without NDT, the cost of maintaining and flying in airplanes would incresae dramatically, while the safety of flying would decrese.
When people step into an airplane they trust that it will get them to their destination with as little turbulenceas possible. NDT Plays a vital role in keeping air travel one of the safest modes of transportation.
Posted by; Adnan
There is no question that the success of the air plane industry is dependent on NDT. Without NDT, the cost of maintaining and flying in airplanes would incresae dramatically, while the safety of flying would decrese.
When people step into an airplane they trust that it will get them to their destination with as little turbulenceas possible. NDT Plays a vital role in keeping air travel one of the safest modes of transportation.
Posted by; Adnan
How essential is nondestructive testing (NDT) to Airplanes
In the aero space industry as with other transportation industries, NDT Can make the difference between life and death. Aircraft Components are inspected before they are assembled into the aircraft and then they are periodically inspected throughout their useful life. Aircraft parts are designed to be as light as possible while still performing their intended function This generally means that components carry very high loads relative to their material strength and small flaws can cause a component to fail. Since aircraft are cycled loaded and unloaded as they fly, land, taxi, and pressurize the cabin, many unfamiliar with the term "fatigue cracking" after some length of time. if you are unfamiliar with the term "fatigue cracking" think about what happends when you bend a paper clip or piece of wire back and forth, eventually it will break. Even parts that are loaded well below the level that caused them to deform can develop fatigue cracks after being cycled for a long time. This is what happends in aircraft. After they are used for a while, fatigue cracks start growing in some of their parts. Cracking can also occur due to other things like a lightning strike. Aircraft have some protection against lightning strikes but occasionally they occur and can results in cracks forming at the strike location like the one shown in the picture.
Another problem that aircraft have is that they are under the constant attack of corosion. When an aircraft lands and the door is opened, the inside of the plane often fills with warm moist air. When the plane takes flight, and reaches altitude, the skin of the air craft becomes very cold due to the temperature of the outside air. This cause the moisture held by the air inside the cabin to condense on the inside of the aircraft skin. The water will collect at low areas and serve as the electrolyte needed for corrosion to occur.
The good news is that aircraft are designed to withstand a certain amount of damage from cracking and corrosion without casue for concern, and NDT Inspectors are trained to find the damage before it becomes a major problem.
Posted by: Adnan
Another problem that aircraft have is that they are under the constant attack of corosion. When an aircraft lands and the door is opened, the inside of the plane often fills with warm moist air. When the plane takes flight, and reaches altitude, the skin of the air craft becomes very cold due to the temperature of the outside air. This cause the moisture held by the air inside the cabin to condense on the inside of the aircraft skin. The water will collect at low areas and serve as the electrolyte needed for corrosion to occur.
The good news is that aircraft are designed to withstand a certain amount of damage from cracking and corrosion without casue for concern, and NDT Inspectors are trained to find the damage before it becomes a major problem.
Posted by: Adnan
Inspection Method of Magnetic Particle Testing
INSPECTION METHOD: MAGNETIC PARTICLE TESTING
SUBJECT HOURS OF TRAINING
LEVEL 1 LEVEL 2 LEVEL 3
1. GENERAL KNOWLEDGE 4 5 1)
2. PHYSICAL PRINCIPLES AND
FUNDAMENTALS OF MAGNETIC
PARTICLES
3 3 2
3. METHODS AND TECHNIQUES 4 4 3
4. EQUIPMENT AND ACCESSORIES 2 3 3
5. CODES, STANDARDS, SPECIFICATIONS
AND PROCEDURES
1 3 8
6. PRESENTATION AND RECORDING OF
RESULTS
2 2 2
7. INTERPRETATION OF RESULTS
LIMITATIONS
- 4 2
TOTAL 16 24 201)
1) In addition to the above 20 hours a general knowledge common core course for level 3 (applicable
to all NDT methods) is recommended, which shall be successfully completed only onc e.
GENERAL KNOWLEDGE COMMON CORE COURSE FOR LEVEL 3:
SUBJECT HOURS OF TRAINING
LEVEL 3
1. NDT, MATERIALS AND PROCESSES 24
2. PROCEDURE WRITING 4
3. QUALITY ASSURANCE AND
STANDARDIZATION -
4
4. ORGANIZATION AND ADMINISTRATION OF
NDT
4
5. QUALIFICATION AND CERTIFICATION OF NDT
PERSONNEL
4
TOTAL 40
SUBJECT HOURS OF TRAINING
LEVEL 1 LEVEL 2 LEVEL 3
1. GENERAL KNOWLEDGE 4 5 1)
2. PHYSICAL PRINCIPLES AND
FUNDAMENTALS OF MAGNETIC
PARTICLES
3 3 2
3. METHODS AND TECHNIQUES 4 4 3
4. EQUIPMENT AND ACCESSORIES 2 3 3
5. CODES, STANDARDS, SPECIFICATIONS
AND PROCEDURES
1 3 8
6. PRESENTATION AND RECORDING OF
RESULTS
2 2 2
7. INTERPRETATION OF RESULTS
LIMITATIONS
- 4 2
TOTAL 16 24 201)
1) In addition to the above 20 hours a general knowledge common core course for level 3 (applicable
to all NDT methods) is recommended, which shall be successfully completed only onc e.
GENERAL KNOWLEDGE COMMON CORE COURSE FOR LEVEL 3:
SUBJECT HOURS OF TRAINING
LEVEL 3
1. NDT, MATERIALS AND PROCESSES 24
2. PROCEDURE WRITING 4
3. QUALITY ASSURANCE AND
STANDARDIZATION -
4
4. ORGANIZATION AND ADMINISTRATION OF
NDT
4
5. QUALIFICATION AND CERTIFICATION OF NDT
PERSONNEL
4
TOTAL 40
Inspection Methods of Ultrasonic Testing
INSPECTION METHOD: ULTRASONIC TESTING
SUBJECT HOURS OF TRAINING
LEVEL 1 LEVEL 2 LEVEL 3
1. GENERAL KNOWLEDGE 4 8 1)
2. TERMINOLOGY, PHYSICAL PRINCIPLES AND
FUNDAMENTALS OF ULTRASONICS
8 8 5
3. TESTING TECHNIQUES AND THEIR
LIMITATIONS
4 8 5
4. EQUIPMENT AND ACCESSORIES 4 6 6
5. CALIBRATION OF THE TESTING SYSTEM 8 12 3
6. SPECIFIC APPLICATIONS 4 12 4
7. CODES, STANDARDS, SPECIFICATIONS AND
PROCEDURES
4 10 9
8. RECORDING AND EVALUATION OF RESULTS 4 10 2
9. SPECIAL TECHNIQUES - 6 6
TOTAL 40 80 401)
1) 1 In addition to the above 40 hours a general knowledge common core course for level 3 (applicable to
all NDT methods) is recommended, which shall be successfully completed only once..
GENERAL KNOWLEDGE COMMON CORE COURSE FOR LEVEL 3:
SUBJECT HOURS OF TRAINING
LEVEL 3
1. NDT, MATERIALS AND PROCESSES 24
2. PROCEDURE STRUCTURE 4
3. QUALITY ASSURANCE AND
STANDARDIZATION -
4
4. ORGANIZATION AND ADMINISTRATION OF
NDT
4
5. QUALIFICATION AND CERTIFICATION OF NDT
PERSONNEL
4
TOTAL 40
SUBJECT HOURS OF TRAINING
LEVEL 1 LEVEL 2 LEVEL 3
1. GENERAL KNOWLEDGE 4 8 1)
2. TERMINOLOGY, PHYSICAL PRINCIPLES AND
FUNDAMENTALS OF ULTRASONICS
8 8 5
3. TESTING TECHNIQUES AND THEIR
LIMITATIONS
4 8 5
4. EQUIPMENT AND ACCESSORIES 4 6 6
5. CALIBRATION OF THE TESTING SYSTEM 8 12 3
6. SPECIFIC APPLICATIONS 4 12 4
7. CODES, STANDARDS, SPECIFICATIONS AND
PROCEDURES
4 10 9
8. RECORDING AND EVALUATION OF RESULTS 4 10 2
9. SPECIAL TECHNIQUES - 6 6
TOTAL 40 80 401)
1) 1 In addition to the above 40 hours a general knowledge common core course for level 3 (applicable to
all NDT methods) is recommended, which shall be successfully completed only once..
GENERAL KNOWLEDGE COMMON CORE COURSE FOR LEVEL 3:
SUBJECT HOURS OF TRAINING
LEVEL 3
1. NDT, MATERIALS AND PROCESSES 24
2. PROCEDURE STRUCTURE 4
3. QUALITY ASSURANCE AND
STANDARDIZATION -
4
4. ORGANIZATION AND ADMINISTRATION OF
NDT
4
5. QUALIFICATION AND CERTIFICATION OF NDT
PERSONNEL
4
TOTAL 40
Inspection Method : Radiographic Testing
INSPECTION METHOD: RADIOGRAPHIC TESTING
SUBJECT HOURS OF TRAINING
LEVEL1 LEVEL 2 LEVEL3
1. GENERAL KNOWLEDGE 4 8 1)
2. PHYSICAL PRINCIPLES OF THE TEST 3 4 3
3. EQUIPMENT- RADIATION SOURCES 3 8 3
4. PHOTOGRAPHIC AND NON-PHOTOGRAPHIC
RECORDING
4 8 4
5. WORK PARAMETERS AND CONDITIONS 4 8 3
6. DEFECTOLOGY 2 4 3
7. SELECTION OF TECHNIQUES 2 8 4
8. CODES, STANDARDS, SPECIFICATIONS AND
PROCEDURES
2 8 9
9. PERSONAL SAFETY AND RADIATION
PROTECTION
16 12 5
10. SPECIAL APPLICATIONS - 4 3
11. RECORDING AND INTERPRETATION OF
RESULTS
- 8 3
TOTAL 40 80 401)
1 In addition to the above 40 hours a general knowledge common core course for level 3 (applicable
to all NDT methods) is recommended, which shall be successfully completed only once..
GENERAL KNOWLEDGE COMMON CORE COURSE FOR LEVEL 3:
SUBJECT HOURS OF TRAINING
LEVEL 3
1. NDT, MATERIALS AND PROCESSES 24
2. PROCEDURE WRITING 4
3. QUALITY ASSURANCE AND
STANDARDIZATION
4
4. ORGANIZATION AND ADMINISTRATION OF
NDT
4
5. QUALIFICATION AND CERTIFICATION OF NDT
PERSONNEL
4
TOTAL 40
SUBJECT HOURS OF TRAINING
LEVEL1 LEVEL 2 LEVEL3
1. GENERAL KNOWLEDGE 4 8 1)
2. PHYSICAL PRINCIPLES OF THE TEST 3 4 3
3. EQUIPMENT- RADIATION SOURCES 3 8 3
4. PHOTOGRAPHIC AND NON-PHOTOGRAPHIC
RECORDING
4 8 4
5. WORK PARAMETERS AND CONDITIONS 4 8 3
6. DEFECTOLOGY 2 4 3
7. SELECTION OF TECHNIQUES 2 8 4
8. CODES, STANDARDS, SPECIFICATIONS AND
PROCEDURES
2 8 9
9. PERSONAL SAFETY AND RADIATION
PROTECTION
16 12 5
10. SPECIAL APPLICATIONS - 4 3
11. RECORDING AND INTERPRETATION OF
RESULTS
- 8 3
TOTAL 40 80 401)
1 In addition to the above 40 hours a general knowledge common core course for level 3 (applicable
to all NDT methods) is recommended, which shall be successfully completed only once..
GENERAL KNOWLEDGE COMMON CORE COURSE FOR LEVEL 3:
SUBJECT HOURS OF TRAINING
LEVEL 3
1. NDT, MATERIALS AND PROCESSES 24
2. PROCEDURE WRITING 4
3. QUALITY ASSURANCE AND
STANDARDIZATION
4
4. ORGANIZATION AND ADMINISTRATION OF
NDT
4
5. QUALIFICATION AND CERTIFICATION OF NDT
PERSONNEL
4
TOTAL 40
Radiographic & Ultra sonic Welding Tests
Radiographic and ultrasonic weld inspection are the two most common methods of non-destructive testing (NDT) used to detect discontinuities within the internal structure of welds. The obvious advantage of both these methods of testing is their ability to help establish the weld’s internal integrity without destroying the welded component. We shall briefly examine these two methods of non-destructive testing (NDT). We shall consider how they are used and what types of welding discontinuities they can be expected to find. We shall examine their advantages over other inspection methods and their limitations.
Radiographic Testing (RT) – This method of weld testing makes use of X-rays, produced by an X-ray tube, or gamma rays, produced by a radioactive isotope. The basic principle of radiographic inspection of welds is the same as that for medical radiography. Penetrating radiation is passed through a solid object, in this case a weld rather that part of the human body, onto a photographic film, resulting in an image of the object's internal structure being deposited on the film. The amount of energy absorbed by the object depends on its thickness and density. Energy not absorbed by the object will cause exposure of the radiographic film. These areas will be dark when the film is developed. Areas of the film exposed to less energy remain lighter. Therefore, areas of the object where the thickness has been changed by discontinuities, such as porosity or cracks, will appear as dark outlines on the film. Inclusions of low density, such as slag, will appear as dark areas on the film while inclusions of high density, such as tungsten, will appear as light areas. All discontinuities are detected by viewing shape and variation in density of the processed film.
Radiographic testing can provide a permanent film record of weld quality that is relatively easy to interpret by trained personnel. This testing method is usually suited to having access to both sides of the welded joint (with the exception of double wall signal image techniques used on some pipe work). Although this is a slow and expensive method of nondestructive testing, it is a positive method for detecting porosity, inclusions, cracks, and voids in the interior of welds. It is essential that qualified personnel conduct radiographic interpretation since false interpretation of radiographs can be expensive and interfere seriously with productivity. There are obvious safety considerations when conducting radiographic testing. X-ray and gamma radiation is invisible to the naked eye and can have serious heath and safety implications. Only suitably trained and qualified personnel should practice this type of testing.
Ultrasonic Testing (UT) – This method of testing makes use of mechanical vibrations similar to sound waves but of higher frequency. A beam of ultrasonic energy is directed into the object to be tested. This beam travels through the object with insignificant loss, except when it is intercepted and reflected by a discontinuity. The ultrasonic contact pulse reflection technique is used. This system uses a transducer that changes electrical energy into mechanical energy. The transducer is excited by a high-frequency voltage, which causes a crystal to vibrate mechanically. The crystal probe becomes the source of ultrasonic mechanical vibration. These vibrations are transmitted into the test piece through a coupling fluid, usually a film of oil, called a couplant. When the pulse of ultrasonic waves strikes a discontinuity in the test piece, it is reflected back to its point of origin. Thus the energy returns to the transducer. The transducer now serves as a receiver for the reflected energy. The initial signal or main bang, the returned echoes from the discontinuities, and the echo of the rear surface of the test piece are all displayed by a trace on the screen of a cathode-ray oscilloscope. The detection, location, and evaluation of discontinuities become possible because the velocity of sound through a given material is nearly constant, making distance measurement possible, and the relative amplitude of a reflected pulse is more or less proportional to the size of the reflector.
One of the most useful characteristics of ultrasonic testing is its ability to determine the exact position of a discontinuity in a weld. This testing method requires a high level of operator training and competence and is dependant on the establishment and application of suitable testing procedures. This testing method can be used on ferrous and nonferrous materials, is often suited for testing thicker sections accessible from one side only, and can often detect finer lines or plainer defects which may not be as readily detected by radiographic testing.
Published & Posted by: Adnan
Radiographic Testing (RT) – This method of weld testing makes use of X-rays, produced by an X-ray tube, or gamma rays, produced by a radioactive isotope. The basic principle of radiographic inspection of welds is the same as that for medical radiography. Penetrating radiation is passed through a solid object, in this case a weld rather that part of the human body, onto a photographic film, resulting in an image of the object's internal structure being deposited on the film. The amount of energy absorbed by the object depends on its thickness and density. Energy not absorbed by the object will cause exposure of the radiographic film. These areas will be dark when the film is developed. Areas of the film exposed to less energy remain lighter. Therefore, areas of the object where the thickness has been changed by discontinuities, such as porosity or cracks, will appear as dark outlines on the film. Inclusions of low density, such as slag, will appear as dark areas on the film while inclusions of high density, such as tungsten, will appear as light areas. All discontinuities are detected by viewing shape and variation in density of the processed film.
Radiographic testing can provide a permanent film record of weld quality that is relatively easy to interpret by trained personnel. This testing method is usually suited to having access to both sides of the welded joint (with the exception of double wall signal image techniques used on some pipe work). Although this is a slow and expensive method of nondestructive testing, it is a positive method for detecting porosity, inclusions, cracks, and voids in the interior of welds. It is essential that qualified personnel conduct radiographic interpretation since false interpretation of radiographs can be expensive and interfere seriously with productivity. There are obvious safety considerations when conducting radiographic testing. X-ray and gamma radiation is invisible to the naked eye and can have serious heath and safety implications. Only suitably trained and qualified personnel should practice this type of testing.
Ultrasonic Testing (UT) – This method of testing makes use of mechanical vibrations similar to sound waves but of higher frequency. A beam of ultrasonic energy is directed into the object to be tested. This beam travels through the object with insignificant loss, except when it is intercepted and reflected by a discontinuity. The ultrasonic contact pulse reflection technique is used. This system uses a transducer that changes electrical energy into mechanical energy. The transducer is excited by a high-frequency voltage, which causes a crystal to vibrate mechanically. The crystal probe becomes the source of ultrasonic mechanical vibration. These vibrations are transmitted into the test piece through a coupling fluid, usually a film of oil, called a couplant. When the pulse of ultrasonic waves strikes a discontinuity in the test piece, it is reflected back to its point of origin. Thus the energy returns to the transducer. The transducer now serves as a receiver for the reflected energy. The initial signal or main bang, the returned echoes from the discontinuities, and the echo of the rear surface of the test piece are all displayed by a trace on the screen of a cathode-ray oscilloscope. The detection, location, and evaluation of discontinuities become possible because the velocity of sound through a given material is nearly constant, making distance measurement possible, and the relative amplitude of a reflected pulse is more or less proportional to the size of the reflector.
One of the most useful characteristics of ultrasonic testing is its ability to determine the exact position of a discontinuity in a weld. This testing method requires a high level of operator training and competence and is dependant on the establishment and application of suitable testing procedures. This testing method can be used on ferrous and nonferrous materials, is often suited for testing thicker sections accessible from one side only, and can often detect finer lines or plainer defects which may not be as readily detected by radiographic testing.
Published & Posted by: Adnan
Inspection of Welding
Inspection of welds
The beam of radiation must be directed to the middle of the section under examination and must be normal to the material surface at that point, except in special techniques where known defects are best revealed by a different alignment of the beam. The length of weld under examination for each exposure shall be such that the thickness of the material at the diagnostic extremities, measured in the direction of the incident beam, does not exceed the actual thickness at that point by more than 6%. The specimen to be inspected is placed between the source of radiation and the detecting device, usually the film in a light tight holder or cassette, and the radiation is allowed to penetrate the part for the required length of time to be adequately recorded.
The result is a two-dimensional projection of the part onto the film, producing a latent image of varying densities according to the amount of radiation reaching each area. It is known as a radiograph, as distinct from a photograph produced by light. Because film is cumulative in its response (the exposure increasing as it absorbs more radiation), relatively weak radiation can be detected by prolonging the exposure until the film can record an image that will be visible after development. The radiograph is examined as a negative, without printing as a positive as in photography. This is because, in printing, some of the detail is always lost and no useful purpose is served.
Before commencing a radiographic examination, it is always advisable to examine the component with one's own eyes, to eliminate any possible external defects. If the surface of a weld is too irregular, it may be desirable to grind it to obtain a smooth finish, but this is likely to be limited to those cases in which the surface irregularities (which will be visible on the radiograph) may make detecting internal defects difficult.
After this visual examination, the operator will have a clear idea of the possibilities of access to the two faces of the weld, which is important both for the setting up of the equipment and for the choice of the most appropriate technique.
Defects such as delaminations and planar cracks are difficult to detect using radiography, which is why penetrants are often used to enhance the contrast in the detection of such defects. Penetrants used include silver nitrate, zinc iodide, chloroform and diiodomethane. Choice of the penetrant is determined by the ease with which it can penetrate the cracks and also with which it can be removed. Diiodomethane has the advantages of high opacity, ease of penetration, and ease of removal because it evaporates relatively quickly. However, it can cause skin burns.
SafetyIndustrial radiography appears to have one of the worst safety profiles of the radiation professions, possibly because there are many operators using strong gamma sources (> 2 Ci) in remote sites with little supervision when compared with workers within the nuclear industry or within hospitals.
Published and Posted by: Adnan
The beam of radiation must be directed to the middle of the section under examination and must be normal to the material surface at that point, except in special techniques where known defects are best revealed by a different alignment of the beam. The length of weld under examination for each exposure shall be such that the thickness of the material at the diagnostic extremities, measured in the direction of the incident beam, does not exceed the actual thickness at that point by more than 6%. The specimen to be inspected is placed between the source of radiation and the detecting device, usually the film in a light tight holder or cassette, and the radiation is allowed to penetrate the part for the required length of time to be adequately recorded.
The result is a two-dimensional projection of the part onto the film, producing a latent image of varying densities according to the amount of radiation reaching each area. It is known as a radiograph, as distinct from a photograph produced by light. Because film is cumulative in its response (the exposure increasing as it absorbs more radiation), relatively weak radiation can be detected by prolonging the exposure until the film can record an image that will be visible after development. The radiograph is examined as a negative, without printing as a positive as in photography. This is because, in printing, some of the detail is always lost and no useful purpose is served.
Before commencing a radiographic examination, it is always advisable to examine the component with one's own eyes, to eliminate any possible external defects. If the surface of a weld is too irregular, it may be desirable to grind it to obtain a smooth finish, but this is likely to be limited to those cases in which the surface irregularities (which will be visible on the radiograph) may make detecting internal defects difficult.
After this visual examination, the operator will have a clear idea of the possibilities of access to the two faces of the weld, which is important both for the setting up of the equipment and for the choice of the most appropriate technique.
Defects such as delaminations and planar cracks are difficult to detect using radiography, which is why penetrants are often used to enhance the contrast in the detection of such defects. Penetrants used include silver nitrate, zinc iodide, chloroform and diiodomethane. Choice of the penetrant is determined by the ease with which it can penetrate the cracks and also with which it can be removed. Diiodomethane has the advantages of high opacity, ease of penetration, and ease of removal because it evaporates relatively quickly. However, it can cause skin burns.
SafetyIndustrial radiography appears to have one of the worst safety profiles of the radiation professions, possibly because there are many operators using strong gamma sources (> 2 Ci) in remote sites with little supervision when compared with workers within the nuclear industry or within hospitals.
Published and Posted by: Adnan
NDT & Welding Inspection Techniques
1)Edge Face should be check and equal from every side.
2)“V” Gap or “V” degree that’s size will be in millimeter and usually is 4mm.
3)Joint cleaning should be done.
4)During Tacking should be checked “Porosity”.
5)Arc length should be set in appropriate position. It can be at 6, 5 or 4 mm. If the arc length will not be set at appropriate position it can be cause of welding defects because in the meanwhile oxygen will attack on metal and create defects. So be careful during this process.
6)If porosity find then it should be clear from DPT until correct form later on test will be done again.
7)“V” degree always checked through Gage and it will be provide by Company.
8)“V” degree Pipe design should be “37.5” according to international standards. It can be reduce if water or some thing, which have no pressure that size, can be 35 pye. But for pressure vessels it should be 37.5.
9)Plate size will be according to international standard 30 degree.
10)Welder stamp should be done on base metal and also show his job card.
11)Every thing should be done accordance to Welding Procedures Specifications. And also checked that Electrode is Heat or not.
12)Filling called film, coating called capping.
13)“V” gap size should be 25mm and after welding should be 28mm and capping size should be 3mm.
14)Edge face should be equaled otherwise joint will not be in correct form and welding electrode material will be settle on beginning place that will be cause of “Lack of Fusion”. Because where welding start that current will be 300 and continue but the plate if thin and that current will apply it can be cause of Lack of fusion.
Which type of metal will be use for Foundation?
Ans: Cast Iron will be use for this purpose. Number of quantity of carbon for making it and have no bending ability.
Mild Steel:
Have low carbon and ability to bend and use for (Non pressure pipe lines).
Carbon Steel:
Use for high-pressure lines, i.e. Boilers, Pressure vessels and steam liners.
Remember:
Always use that electrode which type of base metal.
“P” category always use for piping.
Base Metal Welding Material Wire Type
SA516G-70 E7018 ER70S3
P11 E8018 E80SG
How can you check during welding pre heat temperature?
Ans: Temperature Kit. It will be like Tester or Board marker.
What is the difference between Pipe and Tube?
Ans: When we increase the thickness of the pipe then “OD” outer dia will be increase and “ID” will be decrease but when we increase the thickness of tube that “OD” will be decrease and the “ID” will be increase.
Q: Type of Welding Positions.
Ans: 1F: shows that the welding position will be “FLAT”.
2F: Shows that the welding position will be “Horizontal”.
3F: Shows that the welding position will be “Vertical”.
4F: Shows that the welding position will be “Overhead”(only use for Plate)
5F: shows that the welding position will be “use in Pipe”
6G: Use in Plate and Pipe at 45 degree angle.
6GR: Single, Use of Square tank Only.
Q: What is HAZ?
Ans; HAZ means Heat Affected Zone. During welding when contamination attacks on the weld zone then shielding gases stopped them, because of this a line generated on both sides of welding area. Which call HAZ.
Q: What are the causes of Porosity?Ans: 1) Your hand is not stable.
2) Welding electrode using date has expired.
3) During loading and Unloading Electrode has damaged.
4) Iron has large quantity of humidity.
How can you define Electrode Number?
Ans: Example: E-7018
E: Stands European
70: Stands Tensile: 70x 1000= 70000 Tensile
1: Shows welding position
8: Electrode material specifications
What is Root?
Ans: It is base of the base metal and welding material. It always shows inside of the metal.
What is Capping?
Ans: After completing root, will do capping.
What is Excess of Penetration?
Ans: It always shows inside of the metal on welding zone.
Note: Always consider your welding level than welding position. Concentrate on your hand position.
Arc length always should be 5mm melting point and weld metal.
Causes of porosity:
Loading and unloading, Break, Cause porosity
If the base metal will be rusty, that will be cause of porosity.
As you know that rust generate because of humidity. There is large quantity of humidity consist in air, and air is cause of rust.
Q: How we can check Porosity?
Ans: If it is consist on Surface that can find through DPT and also check through RT, UT and Mechanical Test.
Q: Why we do perform Mechanical Test?
Ans: If the current Requirement was 100 Amperes and it applied during welding 90 Amperes, which will be cause of defects because weld metal and base metal will not be mixed at appropriate level. And when you apply chisel test they will break into different pieces not in one piece and will be thick.
II) If the current requirement is 100 Amperes and was apply during welding 110 Amperes, it will be cause of heat that cause of weakness.
III) Under cut reduce the using period.
Types of Tests:
Butt Joint: All tests will be applicable, RT, UT, DPT, MPT, Mechanical Test.
T Joint: Only DPT will be applicable because it always install in Wall.
Corner Joint; DPT will be applicable.
Edge Ends: DPT
Fillet Joint: Only use for Tank Bottom (Kerosene Oil will be applicable)
Lap Joint; Vacuum Test will be applicable.
Some Important Test:
Hammering Test: It is use for testing strength of welding material. Firstly, we apply chisel on the welding zone and break them suddenly, if it break straight that welding material melt in correct form.
(II) If the ripples will be in straight form and not rise in surface that will be current equaled, otherwise it will be rise on metal surface that shows current is too high.
Remember: In auto mobile industry we see Alloy Wheel Rims. You know that there is big difference between of both wheels of wait.
Front wheel always light than back wheel. It has 3 to 4 kg difference. It make through forging process. There are two different types dyes one male, second female and always use oil around wheel cap so that will not paste with dye. Then 45000 kg load apply on that specific metal and cut inside and make it in a good shape. Then, transfer to CNC machining centre and make it in a good form.
Published & Posted by: ADNAN ASHRAF
2)“V” Gap or “V” degree that’s size will be in millimeter and usually is 4mm.
3)Joint cleaning should be done.
4)During Tacking should be checked “Porosity”.
5)Arc length should be set in appropriate position. It can be at 6, 5 or 4 mm. If the arc length will not be set at appropriate position it can be cause of welding defects because in the meanwhile oxygen will attack on metal and create defects. So be careful during this process.
6)If porosity find then it should be clear from DPT until correct form later on test will be done again.
7)“V” degree always checked through Gage and it will be provide by Company.
8)“V” degree Pipe design should be “37.5” according to international standards. It can be reduce if water or some thing, which have no pressure that size, can be 35 pye. But for pressure vessels it should be 37.5.
9)Plate size will be according to international standard 30 degree.
10)Welder stamp should be done on base metal and also show his job card.
11)Every thing should be done accordance to Welding Procedures Specifications. And also checked that Electrode is Heat or not.
12)Filling called film, coating called capping.
13)“V” gap size should be 25mm and after welding should be 28mm and capping size should be 3mm.
14)Edge face should be equaled otherwise joint will not be in correct form and welding electrode material will be settle on beginning place that will be cause of “Lack of Fusion”. Because where welding start that current will be 300 and continue but the plate if thin and that current will apply it can be cause of Lack of fusion.
Which type of metal will be use for Foundation?
Ans: Cast Iron will be use for this purpose. Number of quantity of carbon for making it and have no bending ability.
Mild Steel:
Have low carbon and ability to bend and use for (Non pressure pipe lines).
Carbon Steel:
Use for high-pressure lines, i.e. Boilers, Pressure vessels and steam liners.
Remember:
Always use that electrode which type of base metal.
“P” category always use for piping.
Base Metal Welding Material Wire Type
SA516G-70 E7018 ER70S3
P11 E8018 E80SG
How can you check during welding pre heat temperature?
Ans: Temperature Kit. It will be like Tester or Board marker.
What is the difference between Pipe and Tube?
Ans: When we increase the thickness of the pipe then “OD” outer dia will be increase and “ID” will be decrease but when we increase the thickness of tube that “OD” will be decrease and the “ID” will be increase.
Q: Type of Welding Positions.
Ans: 1F: shows that the welding position will be “FLAT”.
2F: Shows that the welding position will be “Horizontal”.
3F: Shows that the welding position will be “Vertical”.
4F: Shows that the welding position will be “Overhead”(only use for Plate)
5F: shows that the welding position will be “use in Pipe”
6G: Use in Plate and Pipe at 45 degree angle.
6GR: Single, Use of Square tank Only.
Q: What is HAZ?
Ans; HAZ means Heat Affected Zone. During welding when contamination attacks on the weld zone then shielding gases stopped them, because of this a line generated on both sides of welding area. Which call HAZ.
Q: What are the causes of Porosity?Ans: 1) Your hand is not stable.
2) Welding electrode using date has expired.
3) During loading and Unloading Electrode has damaged.
4) Iron has large quantity of humidity.
How can you define Electrode Number?
Ans: Example: E-7018
E: Stands European
70: Stands Tensile: 70x 1000= 70000 Tensile
1: Shows welding position
8: Electrode material specifications
What is Root?
Ans: It is base of the base metal and welding material. It always shows inside of the metal.
What is Capping?
Ans: After completing root, will do capping.
What is Excess of Penetration?
Ans: It always shows inside of the metal on welding zone.
Note: Always consider your welding level than welding position. Concentrate on your hand position.
Arc length always should be 5mm melting point and weld metal.
Causes of porosity:
Loading and unloading, Break, Cause porosity
If the base metal will be rusty, that will be cause of porosity.
As you know that rust generate because of humidity. There is large quantity of humidity consist in air, and air is cause of rust.
Q: How we can check Porosity?
Ans: If it is consist on Surface that can find through DPT and also check through RT, UT and Mechanical Test.
Q: Why we do perform Mechanical Test?
Ans: If the current Requirement was 100 Amperes and it applied during welding 90 Amperes, which will be cause of defects because weld metal and base metal will not be mixed at appropriate level. And when you apply chisel test they will break into different pieces not in one piece and will be thick.
II) If the current requirement is 100 Amperes and was apply during welding 110 Amperes, it will be cause of heat that cause of weakness.
III) Under cut reduce the using period.
Types of Tests:
Butt Joint: All tests will be applicable, RT, UT, DPT, MPT, Mechanical Test.
T Joint: Only DPT will be applicable because it always install in Wall.
Corner Joint; DPT will be applicable.
Edge Ends: DPT
Fillet Joint: Only use for Tank Bottom (Kerosene Oil will be applicable)
Lap Joint; Vacuum Test will be applicable.
Some Important Test:
Hammering Test: It is use for testing strength of welding material. Firstly, we apply chisel on the welding zone and break them suddenly, if it break straight that welding material melt in correct form.
(II) If the ripples will be in straight form and not rise in surface that will be current equaled, otherwise it will be rise on metal surface that shows current is too high.
Remember: In auto mobile industry we see Alloy Wheel Rims. You know that there is big difference between of both wheels of wait.
Front wheel always light than back wheel. It has 3 to 4 kg difference. It make through forging process. There are two different types dyes one male, second female and always use oil around wheel cap so that will not paste with dye. Then 45000 kg load apply on that specific metal and cut inside and make it in a good shape. Then, transfer to CNC machining centre and make it in a good form.
Published & Posted by: ADNAN ASHRAF
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