Fluorescant Penetrant Inspection

Fluorescant Penetrant Inspection
Equipments:

• Penetrant liquid,
• Solvent Remover,
• Developer,
• Black Light,

Penetrant sıvısı kapiler hareket özelliğine sahiptir ve siyah ışık altında fluorescant özelliği sayesinde parlar. Yüzeye açık süreksizliklerin içerisine belirli bir sürede girer, yüzeyde kalan fazla penetrant; penetrant sükücüler vasıtası ile giderildikten sonra developer uygulanır. Developer; süreksizliğin içerisindeki penetrantı tekrar yüzeye çıkartır ve beyaz rengi sayesinde penetrantla kontrast oluşturarak penetrantıon görünürlüğünü siyah ışık altında 600 kat arttırır.

Ultrasonic Beam Characteristics

Ultrasonic Beam Characteristics
To properly identify discontinuities or defects, the location of the ultrasonic beam must be estimated. This estimation includes taking beam attenuation, beam spread, and beam centerline location into account.
Beam Attenuation
When sound waves travel through non-idealized (i.e., real) materials, there is a pronounced reduction in the signal strength. This phenomenon, known as attenuation, results primarily from two basic causes: diffraction and absorption.
Beam diffraction
When sound waves encounter a finite boundary, abrupt changes in the direction of propagation of the sound wave may occur. This is known as diffraction. Diffraction occurs when the sound beam encounters a boundary such as a crack tip or member edge. Diffraction also occurs continuously as the beam passes from each grain of material to the next. This important type of diffraction is commonly known as scattering. Scattering of the sound beam occurs as a result of the generally coarse-grained properties of metals. Each grain boundary is a small reflector that emits scattered and reflected signals. For very coarse-grained materials, this can actually lead to detectable echoes, which are commonly referred to as "grass," that typically present low-amplitude signals on an A-scan.
Beam absorption
The second cause of attenuation is known as absorption. In beam absorption, the sound energy passing through the test material is directly converted to heat. Absorption in crystalline metals can generally be thought of as a process of converting the signal energy to heat through friction. Describing the actual process of beam absorption is well beyond the scope of what is needed here.
Beam Spread (Beam Divergence)
Beam spreading occurs in all ultrasonic beams. By definition, beam spread occurs because the beam energy does not stay within the cross section of the transducer. Rather, the beam starts out as a cylinder and then, after some distance, spreads into a cone. This spreading reduces the intensity of the wave at each discrete point and, as a result, lowers the amount of energy that could be reflected at a defect. This phenomenon is combated through the use of Distance Amplitude Correction (DAC), which is described later. The angle of beam spread (β) can be approximated using equation 8. This equation gives the angle from the centerline of the beam to the perimeter of the central energy lobe.

What is Ultrasonic

Ultrasonic Sound
The term "ultrasonic" applied to sound refers to anything above the frequencies of audible sound, and nominally includes anything over 20,000 Hz. Frequencies used for medical diagnostic ultrasound scans extend to 10 MHz and beyond.
Sounds in the range 20-100kHz are commonly used for communication and navigation by bats, dolphins, and some other species. Much higher frequencies, in the range 1-20 MHz, are used for medical ultrasound. Such sounds are produced by ultrasonic transducers. A wide variety of medical diagnostic applications use both the echo time and the Doppler shift of the reflected sounds to measure the distance to internal organs and structures and the speed of movement of those structures. Typical is the echocardiogram, in which a moving image of the heart's action is produced in video form with false colors to indicate the speed and direction of blood flow and heart valve movements. Ultrasound imaging near the surface of the body is capable of resolutions less than a millimeter. The resolution decreases with the depth of penetration since lower frequencies must be used (the attenuation of the waves in tissue goes up with increasing frequency.) The use of longer wavelengths implies lower resolution since the maximum resolution of any imaging process is proportional to the wavelength of the imaging wave.

Neutron Imaging

The field of neutron imaging has a broad scope of applications and has played a pivotal role in visualizing and quantifying hydrogenous masses in metallic matrices. The field continues to expand into new applications with the installation of new neutron imaging facilities, the investigation of new imaging techniques and developments in neutron detector technology. Some of the main topics to be discussed are:

• new neutron imaging facilities
• detector development
• phase, stroboscopic, and other novel imaging techniques
• imaging for the hydrogen economy
• industrial imaging applications
• tomography and image reconstruction/analysis methods
• security applications
• fast neutron radiography
• miscellaneous

Eddy-Current Inspection

In order to monitor on-line blade steel quality, MPI has developed high-speed, on-line process control eddy current capabilities to determine three major parameters: hardness, percentage of retained austenite, and impact (toughness) in its manufacturing lines.
New sensor development
Since commercial probes introduce a number of engineering problems, chief among them proximity effects and lift-off measurement errors, a special purpose sensor was developed to overcome these difficulties. A newly constructed encircling coil on a carbide former was found to be insensitive to small random motions of the steel blade due to the relative uniform field within the cross section. In addition, side effect and lift-off measurement errors were virtually eliminated, therefore enabling high-speed, on-line testing. Based on the industrial requirement of monitoring the ambient temperature, a thermocouple was also embedded in the coil former with a protective sheath.
Generic dynamic eddy current testing system
The system interface developed by MPI is completely automated. It is comprised of two eddy current sensors with integrated thermocouples. The thermocouples are directly connected to a standard data acquisition board that is connected to the PC via a serial interface. For the custom-built sensors, shielded cables are utilized to connect to impedance analyzers that in turn are connected to the PC via a fast GPIB interface. Within the PC an appropriate Graphical User Interface (GUI) will allow the operator to determine the impedance calibrated retained austenite value in conjunction with the coil temperature. In addition to the on-line display of the RA and temperature, a software algorithm stores the recorded information for further off-line data processing and statistical analysis.