Nace Rp 0287

[Gisberto Letter]

Anunfortunate characteristic of replica tape is that conventional spring micrometer measurements are most accurate near the middle of each grade's range and least accurate at the outer ends of each grade's range. That is why two other grades, Coarse Minus ( 115 m / 4.5 mils), are used to check and, if necessary, adjust measurements at the upper and lower ends of the primary range.

Inside the primary range, Coarse and X-Coarse tape share a 38 - 64 μm (1.5 - 2.5 mils) "overlap" region. Measurements with conventional micrometers require a complicated and time consuming procedure of averaging one reading using Coarse grade and one reading using X-Coarse grade to achieve reasonable accuracy.

With a single measurement, the PosiTector RTR H produces a more accurate peak-to-valley height measurement HL from Coarse or X-Coarse tapes that has been adjusted for their non-linearity. There is no need to average two or more replicas from different grades of tape AND there is no need to subtract the 50.8 μm / 2 mils of incompressible polyester film. The advantages are a reduction in measurement uncertainty, inspector workload, likelihood of error, and the number of replicas needed by inspectors to assure accuracy.

The PosiTector RTR H can also display a height value (H) that is comparable to what conventional analog spring micrometers would display after the 50.8 μm / 2 mils of incompressible polyester film has been subtracted.

From wired USB to WiFi wireless technology, DeFelsko instruments offer data management solutions for even the most advanced software integrations. Accessing your stored or live streaming data is simpler and more flexible than ever before. PosiTector and PosiTest AT-A instruments have the ability to integrate with third-party software, drones, ROVs, PLCs, and robotic devices using several industry-standard communication protocols.

Replica tape is a long-known method for characterizing a surface. It is simple, relatively inexpensive, and shows good correlation with results from other methods. It has the advantages of ruggedness, relatively low start-up cost, good repeatability and the option of retaining a physical replica of the surface being evaluated. The method is widely used and widely understood. It is particularly useful for measurements on curved surfaces that are difficult to measure directly with other instruments.

It is therefore not surprising that it has become the most popular field method for measuring surface profile. Its operation is described in a number of international standards including ASTM D4417, ISO 8503-5, NACE SP0287, and AS 3894.5.

The PosiTector SPG conforms to Method B of ASTM D4417. The PosiTector SPG measures quickly, and has no per-test cost. It keeps a digital record of each measurement, is less operator dependent, as no burnishing of replica tape is required. It also has a greater range than replica tape.

The PosiTector RTR conforms to Method C of ASTM D4417. It is used together with Testex Replica Tape, a widely used and respected method to measure surface profile. It has the ability to measure on curved surfaces, and gives the user the option to retain the replica tape; a physical replica of the tested surface.

No. The PosiTector RTR Replica Tape Reader is designed for simple operation, featuring easy-to-use menus, an instruction manual, and helpful videos. In lieu of demonstration models, we provide unlimited technical support via telephone and/or email, and a limited 30-day money back guarantee.

The rich text element allows you to create and format headings, paragraphs, blockquotes, images, and video all in one place instead of having to add and format them individually. Just double-click and easily create content.

A rich text element can be used with static or dynamic content. For static content, just drop it into any page and begin editing. For dynamic content, add a rich text field to any collection and then connect a rich text element to that field in the settings panel. Voila!

In our tests on freshly blasted steel with a typical 50-100 micron (2-4 mil) profile, PosiPatches were reused dozens of times with no noticeable wear or leakage. Patch life will vary depending on use- if dragged along the substrate, lifespan will be reduced.

We believe that 10 uses is a very conservative estimate of lifespan and still yields the lowest per-test cost of any commercially available Bresle Method Patch. The below tables compare the per-test costs of various options, using competitive prices found online.

Unequal pulling force during testing caused by uneven adhesive bond lines and coating surfaces can result in random, unexplainable readings. To obtain more repeatable and meaningful adhesion measurements, it is imperative that the pulling force applied to the test dolly is uniformly distributed over the surface being tested.

Both the PosiTest AT-M manual and PosiTest AT-A automatic models compensate for misalignment. The self-aligning, quick-coupling actuator and spherical articulating dolly head enable uniform distribution of the pulling force over the surface being tested, preventing a one-sided pull-off.

With a single measurement, the PosiTector RTR produces a more accurate peak-to-valley height measurement HL from Coarse or X-Coarse tapes that has been adjusted for their non-linearity. There is no need to average two or more replicas from different grades of tape AND there is no need to subtract the 50.8 μm / 2 mils of incompressible polyester film. The advantages are a reduction in measurement uncertainty, inspector workload, likelihood of error, and the number of replicas needed by inspectors to assure accuracy.

The PosiTector RTR can also display a height value (H) that is comparable to what conventional analog spring micrometers would display after the 50.8 μm / 2 mils of incompressible polyester film has been subtracted.

Eddy current techniques are used to nondestructively measure the thickness of nonconductive coatings on nonferrous metal substrates. A coil of fine wire conducting a high-frequency alternating current (above 1 MHz) is used to set up an alternating magnetic field at the surface of the instrument's probe. When the probe is brought near a conductive surface, the alternating magnetic field will set up eddy currents on the surface. The substrate characteristics and the distance of the probe from the substrate (the coating thickness) affect the magnitude of the eddy currents. The eddy currents create their own opposing electromagnetic field that can be sensed by the exciting coil or by a second, adjacent coil.

Magnetic film gages are used to non-destructively measure the thickness of a nonmagnetic coating on ferrous substrates. Most coatings on steel and iron are measured this way. Magnetic gages use one of two principles of operation: magnetic pull-off or magnetic/electromagnetic induction.

Magnetic pull-off gages use a permanent magnet, a calibrated spring, and a graduated scale. The attraction between the magnet and magnetic steel pulls the two together. As the coating thickness separating the two increases, it becomes easier to pull the magnet away. Coating thickness is determined by measuring this pull-off force. Thinner coatings will have stronger magnetic attraction while thicker films will have comparatively less magnetic attraction. Testing with magnetic gages is sensitive to surface roughness, curvature, substrate thickness, and the make up of the metal alloy.

Magnetic induction instruments use a permanent magnet as the source of the magnetic field. A Hall-effect generator or magneto-resistor is used to sense the magnetic flux density at a pole of the magnet. Electromagnetic induction instruments use an alternating magnetic field. A soft, ferromagnetic rod wound with a coil of fine wire is used to produce a magnetic field. A second coil of wire is used to detect changes in magnetic flux.

These electronic instruments measure the change in magnetic flux density at the surface of a magnetic probe as it nears a steel surface. The magnitude of the flux density at the probe surface is directly related to the distance from the steel substrate. By measuring flux density the coating thickness can be determined.

PosiTector users can capture and save an image copy of the current gage display by simultaneously pressing both the (-) and (+) buttons. 100 screen captures are stored in memory and can be accessed within the PosiSoft USB Drive.

Surface profile is defined as a measurement of the maximum peak-to-valley depth created by abrasive impingement against a surface during abrasive blast cleaning operations, or by an impact-type power tool. During abrasive blast cleaning, the mass of the abrasive and the velocity of the abrasive movement created by compressed air generates kinetic energy (the abrasive can reach speeds of over 600 miles per hour as it exits the blast nozzle). When the abrasive impacts the surface, it cuts into the surface (angular abrasives) or peens the surface (round abrasives) and creates a series of peaks and valleys in the surface.

The creation of this peak-valley pattern in the surface effectively increases the surface area, providing an anchor for the coating system. Both the structure and the coating system protecting the structure will move while in service. This movement may be caused by expansion and contraction of the substrate due to temperature fluctuation, or live loads placed onto a structure; for example, traffic crossing a bridge. The surface profile must be compatible with the coating system. Typically, the higher the coating thickness the greater the surface profile depth. Peak density (the number of peaks per unit area) also plays a key role in maintaining adhesion of the coating system and provides greater resistance to corrosion undercutting when the coating system gets damaged while in service.

3a8082e126