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ASTM D5796-20
Standard Test Method for Measurement of Dry Film Thickness of Thin-Film Coil-Coated Systems by Destructive Means Using a Boring Device
Přeložit název
NORMA vydána dne 1.7.2020
Informace o normě:
Označení normy: ASTM D5796-20
Datum vydání normy: 1.7.2020
Kód zboží: NS-999985
Počet stran: 5
Přibližná hmotnost: 15 g (0.03 liber)
Země: Americká technická norma
Kategorie: Technické normy ASTM
Kategorie - podobné normy:
Anotace textu normy ASTM D5796-20 :
Keywords:
borer bit, boring, crater, destructive, dry film, measure stage, micrometer, optical measurement, thickness, thin films, video camera,, ICS Number Code 17.040.20 (Properties of surfaces)
Doplňující informace
| Significance and Use | ||
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3.1 Measurement of dry film thickness of organic coatings by physically cutting through the film and optically observing and measuring the thickness offers the advantage of direct measurement as compared with nondestructive means. 3.2 Constituent coating layers of an overall thickness of a coating system can usually be measured individually by this test method, provide adhesion between each layer is sufficient. (However, this can be difficult in cases where the primer, topcoat, or multiple coating layers have the same, or very similar, appearance.) FIG. 1 Typical Crater Formed by Boring Device Note 1: The drawing is not to scale. It is for illustration
purposes only.
Note 2: 1.1 This test method covers the
measurement of dry film thickness (DFT) of coating films by
microscopic observation of a precision-cut, shallow-angle crater
bored into the coating film. This crater reveals cross sectional
layers appearing as rings, whose width is proportional to the depth
of the coating layer(s) and allows for direct calculation of dry
film thickness.
1.1.1 The Apparatus, Procedure, and Precision and Bias discussions include Method A and Method B. Method A involves the use of an optical measurement apparatus which is no longer commercially available, but remains a valid method of dry film measurement. Method B is a software driven measurement procedure that supersedes Method A. 1.2 The substrate may be any rigid, metallic material, such as cold-rolled steel, hot-dipped galvanized steel, aluminum, etc. The substrate must be planar with the exception of substrates exhibiting “coil set,” which may be held level by the use of the clamping tool on the drilling device. Note 1: Variations in the surface profile of the substrate may
result in misrepresentative organic coating thickness readings.
This condition may exist over substrates such as hot-dipped, coated
steel sheet. This is true of all “precision cut” methods that are
used to determine dry film thickness of organic coatings. This is
why several measurements across the strip may be useful if
substrate surface profile is suspect.
1.3 The range of thickness measurement is 0 to 3.5 mils (0 to 89 μm). Note 2: For DFT measurements of films greater than 3.5 mils
(89μm), but less than 63 mils (1600 μm), a 45° borer may be used in
accordance with this test method, with the exception of 6.8, where
the micrometer reading would provide a direct read-out, and
division by ten would be unnecessary per 4.3.1 Method A.
1.4 Measurements may be made on coil-coated sheet, certain formed products, or on test panels. 1.5 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. 1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. |
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| 2. Referenced Documents | ||
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