18-08-2012, 04:29 PM
Nondestructive Testing Methods
Nondestructive.ppt (Size: 572.5 KB / Downloads: 39)
Magnetic Particle Testing
Magnetic particle inspection is a method that can be used to find surface and near surface flaws in ferromagnetic materials such as steel and iron.
The technique uses the principle that magnetic lines of force (flux) will be distorted by the presence of a flaw in a manner that will reveal it's presence.
The flaw (for example, a crack) is located from the "flux leakage", following the application of fine iron particles, to the area under examination. There are variations in the way the magnetic field is applied.
The iron particles can be applied dry or wet; suspended in a liquid, colored or fluorescent. While magnetic particle inspection is primarily used to find surface breaking flaws, it can also be used to locate sub-surface flaws. But it's effectiveness quickly diminishes depending on the flaw depth and type.
Liquid Penetrant Testing
Liquid penetrant inspection is a method that is used to reveal surface breaking flaws by bleedout of a colored or fluorescent dye from the flaw.
The technique is based on the ability of a liquid to be drawn into a "clean" surface breaking flaw by capillary action.
Emulsifies is applied to the penetrant. Emulsifier mixes with penetrant on the surface, but penetrant in the crack is not emulsified. Emulsifier makes the mixture washable .
Ultrasonic Testing
Ultrasonic inspection uses sound waves of short wavelength and high frequency to detect flaws or measure material thickness. It is used on aircraft, the power stations generating plant, or welds in pressure vessels at an oil refinery or paper mill.
Eddie Current Testing
Eddy current testing is an electromagnetic technique and can only be used on conductive materials. It's applications range from crack detection, to the rapid sorting of small components for either flaws, size variations, or material variation. Commonly it is used in the aerospace, automotive, marine and manufacturinq industries.
When an energized coil is brought near to the surface of a metal component, eddy currents are induced into the specimen. These currents set-up magnetic field that tend to oppose the original magnetic field. The impedance of coil in close proximity to the specimen is effected by the presence of the induced eddy currents in the specimen.
Acoustic Emission Testing
Acoustic emission monitoring (AE) involves listening to the sounds (which are usually inaudible to the human ear) made by a material, structure or machine in use or under load and drawing conclusions about it's "state of health" from what is heard, just as a Doctor would listen to your heart and lungs.
The technique involves attaching one or more ultrasonic microphones to the object and analyzing the sounds using computer based instruments.
Radiography(X-Ray Inspection)
X-rays are produced by high voltage x ray machines whereas gamma rays are produced from radioactive isotopes such as Iridium 192 .The x-ray or gamma rays are placed close to the material to be inspected and they pass through the material and are then captured on film. This film is then processed and the image is obtained as a series of gray shades between black and white.
Nondestructive.ppt (Size: 572.5 KB / Downloads: 39)
Magnetic Particle Testing
Magnetic particle inspection is a method that can be used to find surface and near surface flaws in ferromagnetic materials such as steel and iron.
The technique uses the principle that magnetic lines of force (flux) will be distorted by the presence of a flaw in a manner that will reveal it's presence.
The flaw (for example, a crack) is located from the "flux leakage", following the application of fine iron particles, to the area under examination. There are variations in the way the magnetic field is applied.
The iron particles can be applied dry or wet; suspended in a liquid, colored or fluorescent. While magnetic particle inspection is primarily used to find surface breaking flaws, it can also be used to locate sub-surface flaws. But it's effectiveness quickly diminishes depending on the flaw depth and type.
Liquid Penetrant Testing
Liquid penetrant inspection is a method that is used to reveal surface breaking flaws by bleedout of a colored or fluorescent dye from the flaw.
The technique is based on the ability of a liquid to be drawn into a "clean" surface breaking flaw by capillary action.
Emulsifies is applied to the penetrant. Emulsifier mixes with penetrant on the surface, but penetrant in the crack is not emulsified. Emulsifier makes the mixture washable .
Ultrasonic Testing
Ultrasonic inspection uses sound waves of short wavelength and high frequency to detect flaws or measure material thickness. It is used on aircraft, the power stations generating plant, or welds in pressure vessels at an oil refinery or paper mill.
Eddie Current Testing
Eddy current testing is an electromagnetic technique and can only be used on conductive materials. It's applications range from crack detection, to the rapid sorting of small components for either flaws, size variations, or material variation. Commonly it is used in the aerospace, automotive, marine and manufacturinq industries.
When an energized coil is brought near to the surface of a metal component, eddy currents are induced into the specimen. These currents set-up magnetic field that tend to oppose the original magnetic field. The impedance of coil in close proximity to the specimen is effected by the presence of the induced eddy currents in the specimen.
Acoustic Emission Testing
Acoustic emission monitoring (AE) involves listening to the sounds (which are usually inaudible to the human ear) made by a material, structure or machine in use or under load and drawing conclusions about it's "state of health" from what is heard, just as a Doctor would listen to your heart and lungs.
The technique involves attaching one or more ultrasonic microphones to the object and analyzing the sounds using computer based instruments.
Radiography(X-Ray Inspection)
X-rays are produced by high voltage x ray machines whereas gamma rays are produced from radioactive isotopes such as Iridium 192 .The x-ray or gamma rays are placed close to the material to be inspected and they pass through the material and are then captured on film. This film is then processed and the image is obtained as a series of gray shades between black and white.