This standard is issued under the fixed designation D ; the number 1 This practice is under the jurisdiction of ASTM Committee D01 on Paint and. Related. ASTM D – Download as Word Doc .doc /.docx), PDF File .pdf), Text File .txt) or read online. Normas. 4 Jun ASTM D_物理_自然科学_专业资料。Standard Practice for Nondestructive Measurement of Dry Film Thickness of Nonmagnetic.
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Using the same example, if a two-point verification procedure is adopted, then a two-mil and an eight-mil set of coated standards slightly below and above the intended range of use is appropriate. A one-point or two-point accuracy verification procedure can be performed; typically, the two-point verification provides greater accuracy. The exposed magnet may attract metal filings, which can contaminate the magnet and cause false aastm measurements.
So if your reading is within the spec your fine.
Spot measurements are obtained in each direction up to the maximum surface area coated during the work shift until two consecutive conforming spot measurements are acquired in that direction, or until no additional measurements can be made. Six appendices from version included.
Link to Active This link will always route to the current Active version of the standard. The steps are incorporated by reference in SSPCPA 2 and are completed before obtaining coating thickness measurements to determine conformance to a specified coating thickness range.
DFT of pipe spools not loaded on cart or rack are typically measured individually. No other units of dd7091 are included in this standard.
Adjusting to zero on an uncoated sample of the test specimen is the simplest from of a one-point adjustment. This culminates in a total of 75 spot measurements 15 x 5 and a minimum of gage aetm 15 x 5 x 3. However it will be important to place a measured shim onto the prepared, uncoated pipe and adjust the gage to match the shim thickness to remove any effect of the base metal.
Verifying accuracy of Type 2 gage on a certified coated standard Fig. Referenced Documents purchase separately The documents listed below are referenced within the subject standard but are not provided as part of the standard. It includes definitions of key terms, reference documents, the significance and use of the practice, the advantages and limitations of coating thickness gages, and a description of test specimens.
However, several Type 2 electronic gage manufacturers offer a variety of probe configurations, some of which are less affected by proximity to edges and are designed to better measure the thickness of coatings on edges Fig. Adjustments to the gage may or may not be required. You do not need to zero the gage. If no Restriction Level is specified, default is based on conformance requirement.
Even then, the thickness of the measured layer is the cumulative thickness of that layer and all layers beneath it, down to the base metal. Pipe sections loaded onto a cart or rack can be considered a complete unit Fig.
February 5, at 2: This article was a very helpful reference for me when I was updating my company coating spec. If there asym no place to measure in a given direction, then no measurement in that direction is necessary.
Acceptability of Gage Readings, Spot Measurements, and Area Measurements While individual gage readings that are unusually high or low and cannot be repeated consistently can be discarded, there are limitations on the thickness values representing the spot measurements the average of three gage readings.
Spot measurement definition was expanded. First, aztm the surface is coated for example, with a primeran uncoated surface may no longer be available for subsequent gage adjustments, so the user may want to have a similar uncoated surface prepared and reserved for future gage astk on a given project. This measured distance is displayed as coating thickness by the gages. SSPC-PA2 prescribes a frequency of coating thickness measurement based on the size of the area coated.
The governing specification is responsible for providing the user with the minimum and the maximum coating thickness for each layer, and for the total coating system.
Please help us to share our service with your friends. These factors include, but are not limited to: This practice does not address the use of ultrasonic coating thickness gages.
Untilthe most recent technical changes were published in Maywith a minor editorial revision in to one of the appendices regarding measurements on test panels. The Table enables the specifier to select from five different restriction levels related to spot and area measurements. Method for Measuring the Dry Film Thickness of Coatings on Edges For decades, the industry was cautioned about taking coating thickness measurements within one inch of an edge, let alone on an edge.
No minimum gage accuracy requirement to qualify for use. The manufacturers provide information for the adjustment and use of these gages, normally in the form of operating instructions. It describes the methods and recommended frequency for verifying the accuracy of gages and for adjusting the equipment and lists the reporting recommendations.
While their use has declined, they are still readily available and used by some. Correction for Base Metal Reading if acquired. A frequency of measurement for coated steel beams girders and coated test panels is also provided in the appendices to SSPC-PA 2. It, too, was published in Spot measurements are obtained on repeating structural units or elements of structural units until two consecutive units in each direction are conforming or until there are no more units to test.
If spot measurement variances result in area measurements that do not meet the specification, then additional spot measurements are acquired radiating outward in eight directions from the nonconforming area to determine the magnitude of the non-conforming thickness. ASTM D their uses and how to apply them correctly.
The final step in the process is to adjust the gage on the surface to which the coating will be applied. In general, access to tight areas is easier with Type 2 gages, especially those equipped with separate or remote probes. For the purpose of final acceptance of the total DFT, the cumulative thickness of all coating layers in each area must be no less than the cumulative minimum specified thickness and no greater than the cumulative maximum specified thickness.
The correction curve may or may not cover the full range of the gage, but should cover the intended range of use.