كل شيء عن الــ NDT & Inspection

م.مجدي عليان · 02-11-2006, 09:52 PM

كشف العيوب الداخلية للمعادن باستخدام الموجات الفوق صوتية

http://www.geinspectiontechnologies.com

م.مجدي عليان · 02-11-2006, 09:53 PM

التقنيات التي تسمى الاختبارات الغير إتلافية NDT :

1- الموجات فوق الصوتية Ultrasonic Test - UT
2- التصوير الاشعاعى RadiographicTest - RT
3- السائل المتغلغل Liquid Penetrant Test - PT
4- الحبيبات الممغنطة Magnitic Particles Test - MT
5- الفحص البصري Visual Test - VT

موقع الجمعية الامريكية للإختبارات اللاإتلافية
American Society for Non-destructive Testing
ASNT
http://www.asnt.org

NDT Applications and Theory

http://www.panametrics-ndt.com/ndt/ndt_technology

م.مجدي عليان · 02-11-2006, 09:54 PM

مرفق عرض تقديمى لذلك

وهذة الطرق هى

1- الموجات فوق الصوتية
2- التصوير الاشعاعى
3- الحبيبات الممغنطة
4- الصبغة المتغلغلة
5- التيارات الاعصارية
http://www.ndt-ed.org/GeneralResourc...tro_to_NDT.ppt

م.مجدي عليان · 02-11-2006, 10:08 PM

[

B]NDT Methods
1-Ultrasonic test (UT).
2- Radiography test (RT).
2-Magnetic Particle test (MT)
4- Liquid Penetrant test (PT).
5- Eddy Current test (ET).
6- Neutron Radiography test (NRT)
7- Leak test (LT).
8- Acoustic Emission test (ET).
9- Infra-Red Thermography

10- Visual Inspection (Endoscopy)

NDT methods principles and general applications
Ultrasonic Test
Ultrasonic test is a nondestructive method in which beams of high frequency sound waves that are transmitted into the material being tested are used to detect surface and subsurface flaws. The sound waves travel through the material with some attended loss of energy ( attenuation) and are reflected at interfaces.
The reflected beam is detected and analyzed to define the presence and location of flaws.
•The degree of reflection depends mainly on the physical state of matter on the opposite side of the interface, and to a lesser extent on specific physical properties of that matter. Sound waves almost completely reflected at metal-gas interfaces. Partial reflections occurs at metal-liquid or metal-solid interfaces, with the specific percentage of reflected energy depending mainly on the ratios of certain properties of the matter on opposing side of the interface.
• Cracks, laminations, shrinkage cavities, bursts, pores, bonding faults and other discontinuities that acts as metal gas interfaces can easily be detected.
•Inclusions and other inhomogeneities in the metal being tested can also be detected (even though they may not act as metal-gas interfaces) by causing partial reflection or scattering of the ultrasonic waves or by producing some other detectable affect on the ultrasonic waves.
• Most ultrasonic test is done at frequencies between 1- 25 MHz, which are above the range of the human hearing ( 20 Hz - 20 KHz) .
•Ultrasonic waves are mechanical vibrations , the amplitude of vibrations in metal parts being ultrasonically tested impose stresses well below the elastic limit, thus preventing permanent effects on the parts.
•Ultrasonic test is one of the most widely used methods of nondestructive testing. It is primary application in the testing of metal is the detection and characterisation of internal flaws, it is also used to detect surface flaws, define bonding characteristics, thickness measurements, corrosion detection, determine physical properties, structure, grain size and elastic constants.[/B]

م.مجدي عليان · 02-11-2006, 10:09 PM

PURPOSE OF INSPECTION

The purpose of any Inspection organization is to mandate the safe and cost efficient operation of the facility. It does this by highlighting any deviations from recognized "Corporate or International Standards and Practices" by Operations, Maintenance or Engineering.

Examples of Inspection’s mandates include:

1. Operations

Insuring adherence to established shutdown intervals, scheduling Relieve Valves inspections, recommending equipment repairs, recommending certain corrosion control methods, etc.

2. Maintenance

Insuring adherence to correct welding practices and techniques, performing Relieve Valves test shop audits, providing assistance in repair practices, etc.

3. Engineering

Insuring adherence to required programs, review of project proposals, assistance in developing corrosion inhibition methods and corrosion control programs, etc.

Inspection also provides services in many disciplines to all Divisions, They include:

a) NDT Nondestructive testing

b) Plant & Equipment Inspection

c) Relieve Valves Coordination

d) In-service Inspection Programs and techniques

e) Vents & Drains monitoring

f) Deadleg monitoring

g) corrosion monitoring and control

i) welding practices and control and

j) etc.

Inspection also provides assistance to all divisions in many ways to either maintain or enhance plant reliability. These include:

a) Taking skin temperature readings on heaters

b) Performing routine monitoring of heater firing patterns

c) Performing Positive Material Identification (PMI) for various groups,

d) etc.

م.مجدي عليان · 02-11-2006, 10:12 PM

Ultrasonic Probes and their primary applications

1- Straight beam direct contact Probes
a- Manufacturing induced flaws:
Billets: Inclusions, stringer, pipe
Forging : Inclusions, cracks, segregation’s, seams, flakes, pipe.
Rolled products : Laminations, inclusions, tears, seams, cracks.
Castings: Slag, porosity, cold shuts, tears, shrinkage cracks, inclusions.
b- Service induced flaws :
Fatigue cracks, corrosion, erosion, stress-corrosion cracks.

2- Angle-beam direct contact Probes
a- Manufacturing induced flaws:
Forging : Cracks, seams, laps
Rolled products: Tears, seams, cracks, cupping.
Welds: Slag inclusions, porosity, incomplete fusion, incomplete penetration, Tubing and pipe: Circumferential and longitudinal cracks.
b- Service induced flaws: Fatigue cracks, stress-corrosion cracks.
3-Twin crystal (dual element) direct contact Probes
a- Manufacturing induced flaws:
Plate and sheet: Thickness measurement, lamination detection .
Tubing and pipe: Thickness measurement.
b- Service induced flaws: Wall thinning, corrosion, erosion, stress-corrosion cracks.
4- Immersion Probes
a- Manufacturing induced flaws:
Billets: Inclusions, stringers, pipe.
Forging: Inclusions, cracks, segregation, seams, flakes, pipe.
Rolled products: Laminations, inclusions, tears,seams, cracks.
Welds: Inclusions, porosity, incomplete fusion, complete penetration, drop through, cracks, base metal laminations.
Adhesive-bonded, soldered or brazed products:Lack of bonding.
Composites: Voids, resin rich, resin poor, lack of filaments.
Tubing and pipe: Cicumferential and longitudinal cracks
b- Service induced flaws: Corrosion, fatigue cracks.

Ultrasonic test applications
1- Power equipment- turbine forging, generator rotors, pressure piping, eldments, pressure vessels.
2- Mill components- rolls, shafts drives, etc.
4- Aircraft components- forging stock, frame sections and honeycomb sandwich assemblies.
3- Jet engine parts- turbine, compressor forging and gear blanks.
5- Machinery materials- die blocks, tool steels and drill pipe.
6- Railroad parts- axles, wheels, track and welded rail.
7- Automotive parts- forging, ductile castings and brazed or welded components.

م.مجدي عليان · 02-11-2006, 10:15 PM

Radiographic test

•Radiography is a method used for nondestructive test of components and assemblies that is based on differential absorption of penetrating radiation (either electromagnetic radiation of very short wave length or Particulate radiation) by the part or test piece (object) being inspected. Because of difference in density and variations in thickness of the part or differences in absorption characteristics caused by
variation in composition, different portions of a test piece absorb different amounts of penetrating radiation. Unabsorbed radiation passing through the part can be recorded on film or photosensitive paper, viewed on a fluorescent screen or monitored by various electronic radiation detectors.
Radiography is used to detect features of a component or assembly that exhibit a difference in thickness or physical density as compared to surrounding material.
Large differences are easily detected than small ones.
In general radiography can detect only those feature that have an appreciable thickness in a direction parallel to the radiation beam. This means that the ability of the process to detect planner discontinuities such as cracks depends on proper orientation of the test piece during test.
Discontinuities such as voids and inclusions which have measurable thickness in all directions, can be detected as long as they are not too small in relation to the section thickness. In general, features that exhibit a 2% or more difference in absorption compared to the surrounding material can be detected.

م.مجدي عليان · 02-11-2006, 10:16 PM

Magnetic Particle Test

•Magnetic Particle Test is a method for detecting surface and subsurface discontinuities in ferromagnetic materials. Operation of method depends on the fact that when the material or part under test in magnetized, discontinuities that lie in a direction transverse to the magnetic field will cause a leakage field to be formed at and above the surface of the part. The presence of this leakage fields, and therefore the presence of the discontinuity, is detected by the use if finely divided ferromagnetic particles applied over the surface, some of the particles being gathered and held by the leakage field. This magnetically held collection of particles forms an outlines of the discontinuity, indicates its location, size, shape and extent.
•Magnetic particles are applied over a surface as dry particles or as wet particles on a liquid carrier such as water or oil.
•Ferromagnetic materials include most of the iron, nickel and cobalt alloys.
•Many of the precipitation-hardening steels such as 17-4 PH, 17-7 PH and 15-4 PH stainless steels are magnetic after aging. These materials lose their ferromagnetic properties above a characteristic temperature called the Curie point Although this temperature varies for different materials, the Curie point of most ferromagnetic materials is approximate-ly 760 C ( 1400 F ).
Nonferromagnetic materials can not be tested by this method. Such materials include aluminum alloys, magnis-ium alloys, copper and copper alloys and austenitic stainless steels.
Applications of Magnetic Particle Test
a. Welds.
b. Castings.
c. Wrought metals.
e. Machined parts.
f.Field inspections.
1- Tanks.
2- Vessels.
3-Reactors.
4- Piping.

م.مجدي عليان · 02-11-2006, 10:17 PM

Liquid Penetrant Testing

• Liquid Penetrant Test is a nondestructive method for detection of discontinuities that are open to the surface of solids and essentially nonporous materials, indications of flaws can be found regardless of the size, configuration, internal structure or chemical composition of the work piece being tested and regardless of flaw orientation.
• Liquid penetrants can seep into (and drawn into) various types of minute surface openings (as fine as 4 micro-inch in width) by capillary action. Because of this, the process is well suited for the detection of all types of surface cracks, laps, porosity, shrinkage areas, laminations and similar discontinuities.

• It is used extensively for the inspection of wrought and cast products of both ferrous and nonferrous metals, powder metallurgy parts, ceramics, plastics and glass objects.
• In practice the liquid penetrant process is relatively simple (no electronic systems are involved).
• Equipment generally is simpler and costly than that for most other nondestructive testing methods.
• Establishment of procedures and standards for testing of specific parts or products is usually less difficult than other highly sophisticated testing methods. The liquid penetrant method does not depend on ferromagnetism and the arrangement of the discontinuities is not a factor.
• The penetrant method is good not only for detection of surface flaws in nonmagnetic metals, but also for revealing surface flaws in variety of other nonmagnetic materials

• Liquid penetrant is also used for testing items made from ferromagnetic steels, in some instances, its sensitivity is greater than that of magnetic particle test.

Applications of Liquid Penetrant Test

a. Inspection of tools and dies.
b. Inspection of tanks, vessels, reactors, piping, dryers and
pumps in the chemical, petrochemical, food, paper and
processing industries.
c. Inspection of diesel locomotive, truck and bus parts,
particularly axles, wheels, gears, crankshafts, cylinder
blocks, connecting rods, cylinders, transmission and
frame.
d. Inspection of oil field drilling rigs, drill pipe, casings
and drilling equipment.
e. Leaks.
f. Inspection of aircraft engine parts, propellers, wing
fittings and castings.

م.مجدي عليان · 02-11-2006, 10:18 PM

Eddy Current test

• The Eddy-current method of testing and induction-heating technique used for metal heating, induction hardening and tempering have several similarities. Both are depending on the principles of electromagnetic induction for inducing eddy currents within placed within or adjacent to on or more induction coils. The heating is a result of I R losses caused by the flow of eddy currents in the part. Changes in coupling between the induction coil and the part being tested and changes in the electrical characteristics of the part cause variation in the loading and tuning of the generator .
• The induction heating system is operated at high power level to produce the desired heating rate.

• The system used in eddy current test is usually operated at very low power level to minimize the heating losses and temperature changes. Also, in the eddy current system electrical-loading changes caused variation in the part being tested, such as those caused by presence of flaws or dimensional changes are monitored by electronic circuits.
• In both eddy current testing and induction heating the selection of the operating frequency is governed largely by “Skin effect”. This effect causes the eddy currents to be concentrated toward the surface adjacent to the coils carrying currents that induce them. Skin effect becomes more pronounced with increase in frequency.
• The coils used in eddy current test differ in design from those used in induction heating because of the differences in power level and resolution requirements which necessitate special test coil arrangements to facilitate the monitoring of the electromagnetic field in the vicinity of the part being tested.

• The coils used in eddy current test differ in design from those used in induction heating because of the differences in power level and resolution requirements which necessitate special test coil arrangements to facilitate the monitoring of the electromagnetic field in the vicinity of the part being tested.
• Function of a basic system.
The part to be tested is placed within or adjacent to an electric coil in which an alternating current is flowing. As shown in fig.1 . This alternating current is called the exciting current, causes eddy currents to flow in the part as a result of electromagnetic induction. These currents flow within closed loops in the part and their magnitude and timing (or phase) depend on a) the original or primary field established by the exciting currents. b) the electrical properties of the part.
c) the electromagnetic fields established by currents flowing
within the part.

• The electromagnetic field in the region in the part and surrounding the part depends on both the exciting current from the coil and the eddy currents flowing in the part. The flow of eddy currents in the part depends on the electrical characteristics of the part, the presence or absence of flaws or other discontinuities in the part, and the total electromagnetic field within the part.
• The change in flow of eddy currents caused by the presence of a crack in a pipe is shown in fig.2 the pipe travels along the length of the test coil as shown in fig.2 In sec. AA in fig.2, no crack is present and the eddy current flow is symmetrical. In sec. B-B in fig.2, where crack is present, the eddy-current flow is impeded and changed in direction, causing significant change in the associated electromagnetic field. From fig.2 it is seen that the electromagnetic field surrounding a part depends partly on the properties and characteristics of the part.

• Finally, the condition of the part can be monitored by observing the effect of the resulting field on the electrical characteristics of the exciting coil, such as is its electrical impedance, induced voltage or induced current.
• Alternatively, the effect of the electromagnetic field can be monitored by observing the induced voltage in one or more other coils placed within the field near the part being monitored. Each and all of these changes can have an effect on the exciting coil or other coil or coils placed within the field near the part. The effects most often used to monitor the condition of the part being tested are the electrical impedance of the coil or the induced voltage of either the exciting coil or other adjacent coil or coils.
Application of Eddy Current Testing

a. Flaw detection.
b. Conductivity and permeability sorting.
c. Thickness gauging.
d. Process control.

02-11-2006, 09:52 PM	رقم المشاركة : [11 (permalink)]
م.مجدي عليان عضو تحرير المجلة	كل شيء عن الــ NDT & Inspection كشف العيوب الداخلية للمعادن باستخدام الموجات الفوق صوتية http://www.geinspectiontechnologies.com
م.مجدي عليان عضو تحرير المجلة	التوقيع: تحياتي مجدي عليان =================== سبحان الله و بحمده سبحان الله العظيــــم ===================

02-11-2006, 09:53 PM	رقم المشاركة : [12 (permalink)]
م.مجدي عليان عضو تحرير المجلة	التقنيات التي تسمى الاختبارات الغير إتلافية NDT : 1- الموجات فوق الصوتية Ultrasonic Test - UT 2- التصوير الاشعاعى RadiographicTest - RT 3- السائل المتغلغل Liquid Penetrant Test - PT 4- الحبيبات الممغنطة Magnitic Particles Test - MT 5- الفحص البصري Visual Test - VT موقع الجمعية الامريكية للإختبارات اللاإتلافية American Society for Non-destructive Testing ASNT http://www.asnt.org NDT Applications and Theory http://www.panametrics-ndt.com/ndt/ndt_technology التعديل الأخير تم بواسطة محمد حمزه ; 11-11-2008 الساعة 12:27 AM. سبب آخر: للتوضيح بصورة أكبر
م.مجدي عليان عضو تحرير المجلة	التوقيع: تحياتي مجدي عليان =================== سبحان الله و بحمده سبحان الله العظيــــم ===================

02-11-2006, 09:54 PM	رقم المشاركة : [13 (permalink)]
م.مجدي عليان عضو تحرير المجلة	مرفق عرض تقديمى لذلك وهذة الطرق هى 1- الموجات فوق الصوتية 2- التصوير الاشعاعى 3- الحبيبات الممغنطة 4- الصبغة المتغلغلة 5- التيارات الاعصارية http://www.ndt-ed.org/GeneralResourc...tro_to_NDT.ppt
م.مجدي عليان عضو تحرير المجلة	التوقيع: تحياتي مجدي عليان =================== سبحان الله و بحمده سبحان الله العظيــــم ===================

02-11-2006, 10:08 PM	رقم المشاركة : [14 (permalink)]
م.مجدي عليان عضو تحرير المجلة	NDT Methods [ B]NDT Methods 1-Ultrasonic test (UT). 2- Radiography test (RT). 2-Magnetic Particle test (MT) 4- Liquid Penetrant test (PT). 5- Eddy Current test (ET). 6- Neutron Radiography test (NRT) 7- Leak test (LT). 8- Acoustic Emission test (ET). 9- Infra-Red Thermography 10- Visual Inspection (Endoscopy) NDT methods principles and general applications Ultrasonic Test Ultrasonic test is a nondestructive method in which beams of high frequency sound waves that are transmitted into the material being tested are used to detect surface and subsurface flaws. The sound waves travel through the material with some attended loss of energy ( attenuation) and are reflected at interfaces. The reflected beam is detected and analyzed to define the presence and location of flaws. •The degree of reflection depends mainly on the physical state of matter on the opposite side of the interface, and to a lesser extent on specific physical properties of that matter. Sound waves almost completely reflected at metal-gas interfaces. Partial reflections occurs at metal-liquid or metal-solid interfaces, with the specific percentage of reflected energy depending mainly on the ratios of certain properties of the matter on opposing side of the interface. • Cracks, laminations, shrinkage cavities, bursts, pores, bonding faults and other discontinuities that acts as metal gas interfaces can easily be detected. •Inclusions and other inhomogeneities in the metal being tested can also be detected (even though they may not act as metal-gas interfaces) by causing partial reflection or scattering of the ultrasonic waves or by producing some other detectable affect on the ultrasonic waves. • Most ultrasonic test is done at frequencies between 1- 25 MHz, which are above the range of the human hearing ( 20 Hz - 20 KHz) . •Ultrasonic waves are mechanical vibrations , the amplitude of vibrations in metal parts being ultrasonically tested impose stresses well below the elastic limit, thus preventing permanent effects on the parts. •Ultrasonic test is one of the most widely used methods of nondestructive testing. It is primary application in the testing of metal is the detection and characterisation of internal flaws, it is also used to detect surface flaws, define bonding characteristics, thickness measurements, corrosion detection, determine physical properties, structure, grain size and elastic constants.[/B] التعديل الأخير تم بواسطة م.مجدي عليان ; 02-11-2006 الساعة 10:10 PM.
م.مجدي عليان عضو تحرير المجلة	التوقيع: تحياتي مجدي عليان =================== سبحان الله و بحمده سبحان الله العظيــــم ===================

02-11-2006, 10:09 PM	رقم المشاركة : [15 (permalink)]
م.مجدي عليان عضو تحرير المجلة	Purpose Of Inspection PURPOSE OF INSPECTION The purpose of any Inspection organization is to mandate the safe and cost efficient operation of the facility. It does this by highlighting any deviations from recognized "Corporate or International Standards and Practices" by Operations, Maintenance or Engineering. Examples of Inspection’s mandates include: 1. Operations Insuring adherence to established shutdown intervals, scheduling Relieve Valves inspections, recommending equipment repairs, recommending certain corrosion control methods, etc. 2. Maintenance Insuring adherence to correct welding practices and techniques, performing Relieve Valves test shop audits, providing assistance in repair practices, etc. 3. Engineering Insuring adherence to required programs, review of project proposals, assistance in developing corrosion inhibition methods and corrosion control programs, etc. Inspection also provides services in many disciplines to all Divisions, They include: a) NDT Nondestructive testing b) Plant & Equipment Inspection c) Relieve Valves Coordination d) In-service Inspection Programs and techniques e) Vents & Drains monitoring f) Deadleg monitoring g) corrosion monitoring and control i) welding practices and control and j) etc. Inspection also provides assistance to all divisions in many ways to either maintain or enhance plant reliability. These include: a) Taking skin temperature readings on heaters b) Performing routine monitoring of heater firing patterns c) Performing Positive Material Identification (PMI) for various groups, d) etc.
م.مجدي عليان عضو تحرير المجلة	التوقيع: تحياتي مجدي عليان =================== سبحان الله و بحمده سبحان الله العظيــــم ===================

02-11-2006, 10:12 PM	رقم المشاركة : [16 (permalink)]
م.مجدي عليان عضو تحرير المجلة	Ultrasonic Probes and their primary applications Ultrasonic Probes and their primary applications 1- Straight beam direct contact Probes a- Manufacturing induced flaws: Billets: Inclusions, stringer, pipe Forging : Inclusions, cracks, segregation’s, seams, flakes, pipe. Rolled products : Laminations, inclusions, tears, seams, cracks. Castings: Slag, porosity, cold shuts, tears, shrinkage cracks, inclusions. b- Service induced flaws : Fatigue cracks, corrosion, erosion, stress-corrosion cracks. 2- Angle-beam direct contact Probes a- Manufacturing induced flaws: Forging : Cracks, seams, laps Rolled products: Tears, seams, cracks, cupping. Welds: Slag inclusions, porosity, incomplete fusion, incomplete penetration, Tubing and pipe: Circumferential and longitudinal cracks. b- Service induced flaws: Fatigue cracks, stress-corrosion cracks. 3-Twin crystal (dual element) direct contact Probes a- Manufacturing induced flaws: Plate and sheet: Thickness measurement, lamination detection . Tubing and pipe: Thickness measurement. b- Service induced flaws: Wall thinning, corrosion, erosion, stress-corrosion cracks. 4- Immersion Probes a- Manufacturing induced flaws: Billets: Inclusions, stringers, pipe. Forging: Inclusions, cracks, segregation, seams, flakes, pipe. Rolled products: Laminations, inclusions, tears,seams, cracks. Welds: Inclusions, porosity, incomplete fusion, complete penetration, drop through, cracks, base metal laminations. Adhesive-bonded, soldered or brazed products:Lack of bonding. Composites: Voids, resin rich, resin poor, lack of filaments. Tubing and pipe: Cicumferential and longitudinal cracks b- Service induced flaws: Corrosion, fatigue cracks. Ultrasonic test applications 1- Power equipment- turbine forging, generator rotors, pressure piping, eldments, pressure vessels. 2- Mill components- rolls, shafts drives, etc. 4- Aircraft components- forging stock, frame sections and honeycomb sandwich assemblies. 3- Jet engine parts- turbine, compressor forging and gear blanks. 5- Machinery materials- die blocks, tool steels and drill pipe. 6- Railroad parts- axles, wheels, track and welded rail. 7- Automotive parts- forging, ductile castings and brazed or welded components.
م.مجدي عليان عضو تحرير المجلة	التوقيع: تحياتي مجدي عليان =================== سبحان الله و بحمده سبحان الله العظيــــم ===================

02-11-2006, 10:15 PM	رقم المشاركة : [17 (permalink)]
م.مجدي عليان عضو تحرير المجلة	Radiographic test Radiographic test •Radiography is a method used for nondestructive test of components and assemblies that is based on differential absorption of penetrating radiation (either electromagnetic radiation of very short wave length or Particulate radiation) by the part or test piece (object) being inspected. Because of difference in density and variations in thickness of the part or differences in absorption characteristics caused by variation in composition, different portions of a test piece absorb different amounts of penetrating radiation. Unabsorbed radiation passing through the part can be recorded on film or photosensitive paper, viewed on a fluorescent screen or monitored by various electronic radiation detectors. Radiography is used to detect features of a component or assembly that exhibit a difference in thickness or physical density as compared to surrounding material. Large differences are easily detected than small ones. In general radiography can detect only those feature that have an appreciable thickness in a direction parallel to the radiation beam. This means that the ability of the process to detect planner discontinuities such as cracks depends on proper orientation of the test piece during test. Discontinuities such as voids and inclusions which have measurable thickness in all directions, can be detected as long as they are not too small in relation to the section thickness. In general, features that exhibit a 2% or more difference in absorption compared to the surrounding material can be detected.
م.مجدي عليان عضو تحرير المجلة	التوقيع: تحياتي مجدي عليان =================== سبحان الله و بحمده سبحان الله العظيــــم ===================

02-11-2006, 10:16 PM	رقم المشاركة : [18 (permalink)]
م.مجدي عليان عضو تحرير المجلة	Magnetic Particle Test Magnetic Particle Test •Magnetic Particle Test is a method for detecting surface and subsurface discontinuities in ferromagnetic materials. Operation of method depends on the fact that when the material or part under test in magnetized, discontinuities that lie in a direction transverse to the magnetic field will cause a leakage field to be formed at and above the surface of the part. The presence of this leakage fields, and therefore the presence of the discontinuity, is detected by the use if finely divided ferromagnetic particles applied over the surface, some of the particles being gathered and held by the leakage field. This magnetically held collection of particles forms an outlines of the discontinuity, indicates its location, size, shape and extent. •Magnetic particles are applied over a surface as dry particles or as wet particles on a liquid carrier such as water or oil. •Ferromagnetic materials include most of the iron, nickel and cobalt alloys. •Many of the precipitation-hardening steels such as 17-4 PH, 17-7 PH and 15-4 PH stainless steels are magnetic after aging. These materials lose their ferromagnetic properties above a characteristic temperature called the Curie point Although this temperature varies for different materials, the Curie point of most ferromagnetic materials is approximate-ly 760 C ( 1400 F ). Nonferromagnetic materials can not be tested by this method. Such materials include aluminum alloys, magnis-ium alloys, copper and copper alloys and austenitic stainless steels. Applications of Magnetic Particle Test a. Welds. b. Castings. c. Wrought metals. e. Machined parts. f.Field inspections. 1- Tanks. 2- Vessels. 3-Reactors. 4- Piping.
م.مجدي عليان عضو تحرير المجلة	التوقيع: تحياتي مجدي عليان =================== سبحان الله و بحمده سبحان الله العظيــــم ===================

02-11-2006, 10:17 PM	رقم المشاركة : [19 (permalink)]
م.مجدي عليان عضو تحرير المجلة	Liquid Penetrant Testing Liquid Penetrant Testing • Liquid Penetrant Test is a nondestructive method for detection of discontinuities that are open to the surface of solids and essentially nonporous materials, indications of flaws can be found regardless of the size, configuration, internal structure or chemical composition of the work piece being tested and regardless of flaw orientation. • Liquid penetrants can seep into (and drawn into) various types of minute surface openings (as fine as 4 micro-inch in width) by capillary action. Because of this, the process is well suited for the detection of all types of surface cracks, laps, porosity, shrinkage areas, laminations and similar discontinuities. • It is used extensively for the inspection of wrought and cast products of both ferrous and nonferrous metals, powder metallurgy parts, ceramics, plastics and glass objects. • In practice the liquid penetrant process is relatively simple (no electronic systems are involved). • Equipment generally is simpler and costly than that for most other nondestructive testing methods. • Establishment of procedures and standards for testing of specific parts or products is usually less difficult than other highly sophisticated testing methods. The liquid penetrant method does not depend on ferromagnetism and the arrangement of the discontinuities is not a factor. • The penetrant method is good not only for detection of surface flaws in nonmagnetic metals, but also for revealing surface flaws in variety of other nonmagnetic materials • Liquid penetrant is also used for testing items made from ferromagnetic steels, in some instances, its sensitivity is greater than that of magnetic particle test. Applications of Liquid Penetrant Test a. Inspection of tools and dies. b. Inspection of tanks, vessels, reactors, piping, dryers and pumps in the chemical, petrochemical, food, paper and processing industries. c. Inspection of diesel locomotive, truck and bus parts, particularly axles, wheels, gears, crankshafts, cylinder blocks, connecting rods, cylinders, transmission and frame. d. Inspection of oil field drilling rigs, drill pipe, casings and drilling equipment. e. Leaks. f. Inspection of aircraft engine parts, propellers, wing fittings and castings.
م.مجدي عليان عضو تحرير المجلة	التوقيع: تحياتي مجدي عليان =================== سبحان الله و بحمده سبحان الله العظيــــم ===================

02-11-2006, 10:18 PM	رقم المشاركة : [20 (permalink)]
م.مجدي عليان عضو تحرير المجلة	Eddy Current test Eddy Current test • The Eddy-current method of testing and induction-heating technique used for metal heating, induction hardening and tempering have several similarities. Both are depending on the principles of electromagnetic induction for inducing eddy currents within placed within or adjacent to on or more induction coils. The heating is a result of I R losses caused by the flow of eddy currents in the part. Changes in coupling between the induction coil and the part being tested and changes in the electrical characteristics of the part cause variation in the loading and tuning of the generator . • The induction heating system is operated at high power level to produce the desired heating rate. • The system used in eddy current test is usually operated at very low power level to minimize the heating losses and temperature changes. Also, in the eddy current system electrical-loading changes caused variation in the part being tested, such as those caused by presence of flaws or dimensional changes are monitored by electronic circuits. • In both eddy current testing and induction heating the selection of the operating frequency is governed largely by “Skin effect”. This effect causes the eddy currents to be concentrated toward the surface adjacent to the coils carrying currents that induce them. Skin effect becomes more pronounced with increase in frequency. • The coils used in eddy current test differ in design from those used in induction heating because of the differences in power level and resolution requirements which necessitate special test coil arrangements to facilitate the monitoring of the electromagnetic field in the vicinity of the part being tested. • The coils used in eddy current test differ in design from those used in induction heating because of the differences in power level and resolution requirements which necessitate special test coil arrangements to facilitate the monitoring of the electromagnetic field in the vicinity of the part being tested. • Function of a basic system. The part to be tested is placed within or adjacent to an electric coil in which an alternating current is flowing. As shown in fig.1 . This alternating current is called the exciting current, causes eddy currents to flow in the part as a result of electromagnetic induction. These currents flow within closed loops in the part and their magnitude and timing (or phase) depend on a) the original or primary field established by the exciting currents. b) the electrical properties of the part. c) the electromagnetic fields established by currents flowing within the part. • The electromagnetic field in the region in the part and surrounding the part depends on both the exciting current from the coil and the eddy currents flowing in the part. The flow of eddy currents in the part depends on the electrical characteristics of the part, the presence or absence of flaws or other discontinuities in the part, and the total electromagnetic field within the part. • The change in flow of eddy currents caused by the presence of a crack in a pipe is shown in fig.2 the pipe travels along the length of the test coil as shown in fig.2 In sec. AA in fig.2, no crack is present and the eddy current flow is symmetrical. In sec. B-B in fig.2, where crack is present, the eddy-current flow is impeded and changed in direction, causing significant change in the associated electromagnetic field. From fig.2 it is seen that the electromagnetic field surrounding a part depends partly on the properties and characteristics of the part. • Finally, the condition of the part can be monitored by observing the effect of the resulting field on the electrical characteristics of the exciting coil, such as is its electrical impedance, induced voltage or induced current. • Alternatively, the effect of the electromagnetic field can be monitored by observing the induced voltage in one or more other coils placed within the field near the part being monitored. Each and all of these changes can have an effect on the exciting coil or other coil or coils placed within the field near the part. The effects most often used to monitor the condition of the part being tested are the electrical impedance of the coil or the induced voltage of either the exciting coil or other adjacent coil or coils. Application of Eddy Current Testing a. Flaw detection. b. Conductivity and permeability sorting. c. Thickness gauging. d. Process control.
م.مجدي عليان عضو تحرير المجلة	التوقيع: تحياتي مجدي عليان =================== سبحان الله و بحمده سبحان الله العظيــــم ===================

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كل شيء عن الــ NDT & Inspection

بإشراف : محمد حمزه ، هانى شرف الدين