AASHTO T65M-13 pdf free download
AASHTO T65M-13 pdf free download.Mass [Weight] of Coating on lron and Steel Articles with Zinc or Zinc-Alloy Coatings.
6. SAMPLING
6.1. Zinc-C’oated Sheets—Samples for mass [weight]-of-coating determination shall be secured in accordance with ASTM A653/A653M, A792/A792M, A875/A875M, A1046/A1046M, or A1063/A1063M depending on the type of coating.
Note 2—For convenience in calculating test results in SI units, the specimen should have an area of 3330 mm2 of sheet (57.7 ± 0.1 mm square or 65.1 ± 0.1 mm in diameter). For results to be reported in inch-pound units, the specimen should have an area of 5.08 in.2 of sheet (2.25 ± 0.01 in. square or 2.54 ± 0.01 in. in diameter). The mass [weight] of coating in grams on a specimen of that area is numerically equal to the mass [weight] of coating in ounces per square foot of sheet.
6.2. Zinc-Ojated Wire—Samples shall be secured as designated in the appropriate specification. The
specimen of wire may be of any length greater than 305 mm [12 in.], but preferably about 610 mm
[24 in.]. Where a continuous length is not available, shorter lengths totaling more than 305 mm
[12 in.], but preferably about 610 mm [24 in.], shall be used. Because the density of the steel is
known to be 7830 kg/rn3 or [0.283 lb/in.3], it is not necessary to use a specific length of specimen.
6.3. Zinc-Coated Articles Other Than Sheet or Wire—Samples for mass [weight] of coating determination shall be secured as designated in the appropriate specification. Except as otherwise provided, the specimens should have a minimum area of 2000 mm2 [3 in.2] of zinc-coated surface. For very small items, several pieces may have to be stripped to obtain the minimum area.
6.3.1. In the case of threaded articles, such as bolts and screws, the determination shall be made on a portion of the articles that does not include any thread.
7. PROCEDURE
7.1. Strip the zinc coating from the specimens by using one of the following methods: hydrochloric acid (1+ 1), hydrochloric acid-antimony trichloride solution, or sulfuric acid (2+75). For zinc alloy coatings containing less than 90 percent zinc, the stripping shall be done using hydrochloric acid (1+1) or sulfuric acid (25+75).
7.2. Clean the specimens by washing with solvent naphtha or other suitable solvent, then rinse with alcohol and dry thoroughly.
7.3. Determine the mass [weight] of the specimens individually to the nearest 0.01 g, except for articles other than sheet or wire with a specimen mass [weight] greater than 125 g. For articles other than sheet or wire with a specimen mass [weight] greater than 125 g, determine the mass (weight) to at least the nearest 0.1 g. After determining the mass [weight], immerse each specimen singly in the stripping solution and allow to remain until the violent evolution of hydrogen has ceased and only a few bubbles are being evolved. This requires about 15 to 30 s, except in the case of sherardized coatings, which require a somewhat longer time. The same solution may be used repeatedly until the time required for stripping becomes inconveniently long. The temperature of the stripping solution shall at no time exceed 38°C [100°F]. After stripping, wash the specimens by scrubbing them under running water, dip in hot water, and wipe or blow dry. Determine the mass [weight] of the specimens again, to the same precision as in the initial determination.AASHTO T65M-13 pdf download.
