Practical demonstration from a professional with 13 years experience

Radiographic Testing Practical Video

MISTRAS CAME TO OCEAN CORP TO GIVE US A RT DEMONSTRATION.

 Here is a calculated 2 MR/HR boundary for compliance with radiation safety therefore no one get overexposed with radiation
The roentgen (R, also röntgen) is an obsolete unit of measurement for the kerma of X-rays and gamma rays up to 3 MeV. It is named after the German physicist Wilhelm Röntgen, the man who discovered X-rays. Originating in 1908, this unit has been redefined and renamed over the years.^[1] It was last defined by the US National Institute of Standards and Technology (NIST) in 1998 as 2.58×10⁻⁴ C/kg, (1 C/kg = 3876 R,) with a recommendation that the definition be given in every document where the roentgen is used.^[2] One roentgen of air kerma deposits 0.00877 gray (0.877 rad) of absorbed dose in dry air, or 0.0096 gray (0.96 rad) in soft tissue.^[3] One roentgen (air kerma) of X-rays may deposit anywhere from 0.01 to more than 0.04 gray (1 to 4 rad) in bone depending on the beam energy.^[4] This tissue-dependent conversion from roentgen to rad is called the F-factor in radiotherapy contexts. The conversion depends on the ionizing energy of a standard medium, which is ambiguous in the latest NIST definition. Even where the standard medium is fully defined, the ionizing energy of the calibration and target mediums are often not precisely known.

Radiographic Testing (RT), or industrial radiography, is a nondestructive testing (NDT) method of inspecting materials for hidden flaws by using the ability of short wavelength electromagnetic radiation (high energy photons) to penetrate various materials.
 
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 ultrasonics is the preferred method for detecting this type of discontinuity.

ROV UMBILICAL

Video Monitor or video suite including a video switcher, video recorders and monitors are connected to the Surface Control Unit. The ROV's camera(s) are routed to the monitor(s).

The Hand Controller used by the ROV pilot to 'fly' the ROV as he views the video monitor and other sensor information displayed on the video overlay, is connected to the Surface Control Unit by a 5 metre lead. All of the vehicle's control functions are incorporated in the Hand Control Unit. These include camera pan and/or tilt, autopilot functions, thruster trim controls, speed, direction, dive, surface and lighting intensity. Spare capacity for additional control functions is included.

An Umbilical connects between the Surface Control Unit and the ROV. For free swimming applications a tough, flexible, polyurethane sheathed umbilical is used. The umbilical contains power conductors to the ROV as well as control signal and video conductors. Spare conductors are provided for accessories such as sonar, survey sensors, CP probes and tools.

Launch and Recovery. The umbilical cable is designed to lift the ROV during the launch or recovery stages. It can be stored on a winch fitted with a slip ring for this purpose. However some operators save the cost of a dedicated winch and use a warping drum to take the weight of the vehicle during this process. The umbilical is coiled in a figure of eight to avoid any kinking and is then led to the warping drum from which it passes over an umbilical sheave to the ROV. When the ROV has been launched and sufficient umbilical has been deployed, the umbilical can be 'stopped' by taking a reverse turn on the warping drum.

The Umbilical Sheave can be fitted to a conveniently located ship's crane, davit or 'A' frame. In order to avoid damage to the umbilical, the sheave wheel must have a greater radius than the minimum bend radius of the umbilical.

ROV CONTROLS WITH VIDEO

ROVs range in size from that of a bread box to a small truck. Deployment and recovery operations range from simply dropping the ROV over the side of a small boat to complex deck operations involving large winches for lifting and A-frames to swing the ROV back onto the deck. Some even have “garages” that are lowered to the bottom. The cabled ROV then leaves the garage to explore, returning when the mission is completed. In most cases, however, ROV operations are simpler and safer to conduct than any type of occupied-submersible or diving operation.

Remotely Operated Vehicles (ROV)

Remotely operated underwater vehicles (ROVs) are unoccupied, highly maneuverable underwater robots operated by a person aboard a surface vessel. They are linked to the ship by a group of cables that carry electrical signals back and forth between the operator and the vehicle. Most are equipped with at least a video camera and lights. Additional equipment is commonly added to expand the vehicle’s capabilities. These may include a still camera, a manipulator or cutting arm, water samplers, and instruments that measure water clarity, light penetration, and temperature. First developed for industrial purposes, such as internal and external inspections of pipelines and the structural testing of offshore platforms, ROVs are now used for many applications, many of them scientific. They have proven extremely valuable in ocean exploration, and are also used for educational programs at aquaria and to link to scientific expeditions live via the internet.

ROV at work in an underwater oil and gas field. The ROV is operating a subsea torque tool (wrench) on a valve on the subsea structure.

Rov Instruction

A remotely operated vehicle (ROV) is a tethered underwater vehicle. They are common in deepwater industries such as offshore hydrocarbon extraction. An ROV may sometimes be called a remotely operated underwater vehicle to distinguish it from remote control vehicles operating on land or in the air. ROVs are unoccupied, highly maneuverable and operated by a person aboard a vessel. They are linked to the ship by a tether (sometimes referred to as an umbilical cable), a group of cables that carry electrical power, video and data signals back and forth between the operator and the vehicle. High power applications will often use hydraulics in addition to electrical cabling. Most ROVs are equipped with at least a video camera and lights. Additional equipment is commonly added to expand the vehicle’s capabilities. These may include sonars, magnetometers, a still camera, a manipulator or cutting arm, water samplers, and instruments that measure water clarity, light penetration and temperature.

Geometric Unsharpness in Radiography

Radiographic Testing

My Classmate Eli.

Forklift test

This is our forklift test in Rigging Class. We had to maneuver an obstacle Course.

UT Phased Array during Meet and Greet Day

Phased array (PA) ultrasonics is an advanced method of ultrasonic testing that has applications in medical imaging and industrial nondestructive testing. Common applications are to examine the heart noninvasively or to find flaws in manufactured materials such as welds. Single-element (non phased array) probes—known technically as monolithic probes—emit a beam in a fixed direction. To test or interrogate a large volume of material, a conventional probe must generally be physically turned or moved to sweep the beam through the area of interest. In contrast the beam from a phased array probe can be moved electronically, without moving the probe, and can be swept through a wide volume of material at high speed. The beam is controllable because a phased array probe is made up of multiple small elements, each of which can be pulsed individually at a computer-calculated timing. The term phased refers to the timing, and the term array refers to the multiple elements. Phased array ultrasonic testing is based on principles of wave physics that also have applications in fields such as optics and electromagnetic antennae.

Eddy currents (also called Foucault currents^[1]) are electric currents induced in conductors when a conductor is exposed to a changing magnetic field; due to relative motion of the field source and conductor or due to variations of the field with time. This can cause a circulating flow of electrons, or current, within the body of the conductor. These circulating eddies of current have inductance and thus induce magnetic fields. These fields can cause repulsive, attractive,^[2] propulsion and drag effects. The stronger the applied magnetic field, or the greater the electrical conductivity of the conductor, or the faster the field changes, then the greater the currents that are developed and the greater the fields produced.

Tube inspection using Eddy Current.

Tube Inspection using Eddy Current

This technique is ideal for detection and sizing of cracks, corrosion, erosion, and mechanical damage. It is widely used in the Refining, Petrochemical and Power generation Industries for inspection of non-ferromagnetic tubes 



eddy current

Eddy current probe testing

Electromagnetic Testing (ET)

Electromagnetic Testing (ET)
There are a number of electromagnetic testing methods but the focus here will be on eddy current testing. In eddy current testing, electrical currents (eddy currents) are generated in a conductive material by a changing magnetic field. The strength of these eddy currents can be measured. Material defects cause interruptions in the flow of the eddy currents which alert the inspector to the presence of a defect or other change in the material. Eddy currents are also affected by the electrical conductivity and magnetic permeability of a material, which makes it possible to sort some materials based on these properties. The technician in the image is inspecting an aircraft wing for defects.

Penetrant Testing (PT)

Penetrant Testing (PT)
With this testing method, the test object is coated with a solution that contains a visible or fluorescent dye. Excess solution is then removed from the surface of the object but is left in surface breaking defects. A developer is then applied to draw the penetrant out of the defects. With fluorescent dyes, ultraviolet light is used to make the bleedout fluoresce brightly, thus allowing imperfections to be readily seen. With visible dyes, a vivid color contrast between the penetrant and developer makes the bleedout easy to see. The red indications in the image represent a defect in this component.

Ultrasonic Testing (UT)

Ultrasonic Testing (UT)
In ultrasonic testing, high-frequency sound waves are transmitted into a material to detect imperfections or to locate changes in material properties. The most commonly used ultrasonic testing technique is pulse echo, whereby sound is introduced into a test object and reflections (echoes) from internal imperfections or the part's geometrical surfaces are returned to a receiver. Below is an example of shear wave weld inspection. Notice the indication extending to the upper limits of the screen. This indication is produced by sound reflected from a defect within the weld.

Magnetic Particle Testing (MT)

Magnetic Particle Testing (MT)
This NDT method is accomplished by inducing a magnetic field in a ferromagnetic material and then dusting the surface with iron particles (either dry or suspended in liquid). Surface and near-surface flaws disrupt the flow of the magnetic field within the part and force some of the field to leak out at the surface. Iron particles are attracted and concentrated at sites of the magnetic flux leakages. This produces a visible indication of defect on the surface of the material. The images above demonstrate a component before and after inspection using dry magnetic particles.

Radiography (RT)

Radiography (RT)
RT involves using penetrating gamma- or X-radiation on materials and products to look for defects or examine internal or hidden features. An X-ray generator or radioactive isotope is used as the source of radiation. Radiation is directed through a part and onto film or other detector. The resulting shadowgraph shows the internal features and soundness of the part. Material thickness and density changes are indicated as lighter or darker areas on the film or detector. The darker areas in the radiograph below represent internal voids in the component.

Visual and Optical Testing (VT)

Visual and Optical Testing (VT)
The most basic NDT method is visual examination. Visual examiners follow procedures that range from simply looking at a part to see if surface imperfections are visible, to using computer controlled camera systems to automatically recognize and measure features of a component.

liquid Penetrant Testing

Liquid Penetrant Testing

Dye penetrant inspection (DPI), also known as liquid penetrant examination (LPE), is a type of non-destructive testing used generally in the detection of surface flaws in non-ferrous alloys. The dye penetrant inspection (DPI) method employs a penetrating liquid, applied to the surface of the component and enters the flaw, crack or seam. After the excess penetrant has been cleared from the surface, the penetrant is drawn back out and the crack is observed using a white light or UV light. Dye penetrant inspection (DPI) can also be used for the inspection of ferrous materials where magnetic particle inspection is difficult to apply. In some cases Dye penetrant inspection (DPI) can be used on non-metallic materials. Variations include the use of fluorescent dyes, where a black (UV) light is used to illuminate the residual penetrant. This Dye penetrant inspection (DPI) technique has even higher sensitivity than normal LPE but can only be used in the absence of other light sources.

Dye penetrant inpection can be applied to any non-porous clean material, metallic or non-metallic material, but is unsuitable for dirty or rough surfaces.

Shear wave ultrasonic testing

Shear Wave, sometimes referred to as Angle Beam Ultrasonic testing, can be used to inspect pipe, critical welds in pressure vessels and plate weldments, and can be used to inspect cracks for depth, size, length and orientation.

ultrasonic testing calibration

ultrasonic testing calibration

Ultrasonic inspection methods of Non-Destructive Testing (NDT) use beams of sound waves (vibrations) of short wavelength and high frequency, transmitted from a probe and detected by the same or other probes. The sound energy is propagated in the material in form of longitudinal or shear wave modes and is ideal for the detections of two dimensional types of defects, cracks, delaminations, fusion defects. Usually, pulsed beams of ultrasound are used and in the simplest instruments a single probe, hand held, is placed on the specimen surface. During an ultrasonic inspection, an oscilloscope display with a time base shows the time it takes for an ultrasonic pulse to travel to a reflector (a flaw, the back surface or other free surface) in terms of distance traveled across the oscilloscope screen. The height of the reflected pulse is related to the flaw size as seen from the transmitter probe. The relationship of flaw size, distance and reflectivity are complex, and a considerable skill is required to interpret the display. Complex mutiprobe systems are also used with mechanical probe movement and digitization of signals, followed by computer interpretation are developing rapidly. Through the use of ultrasonic inspection test principles, internal material flaws can be detected and evaluated. Depending on the test application and or part configuration, inspection may be accomplished in either contact or immersion methods.



Magnetic Particle Testing

Rigging Class.

Magnetic Particle Testing

Magnetic Particle Testing

Overview of the classes I have taken for Inspection training since November 14th, 2011

Thus far I have completed First Aid, Hazardous Materials, Materials and Processes, Visual Testing, Liquid Penetrant, and Ultra Sonic Testing at The Ocean Corporation School for Non Destructive Testing.