Designation: D – 01Standard Test Method for Evaluating Adhesion by Knife1 This standard is issued under the fixed desig. From ASTM D Standard Test Method for Evaluating Adhesion by Knife. Section 3 | Summary of Test Method. Adhesion is determined by making an “ X”. Buy ASTM D Standard Test Method for Evaluating Adhesion by Knife from SAI Global.
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March 3, at Although d677 method is a qualitative and a subjective 7. Inspection Instruments Pipeline Coatings — Volume 2: See DD and D April 7, at 6: A description of the adhesion criteria is included in Table 3. For coatings up to 2.
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Adhesion tests that consistently reveal an adhesive break between coats or a cohesive break within a coat do not provide any information relative to the adhesion of the coating or coating system to the substrate. Eugen, The following comes from the author: When the coating is greater than 5-mils thick an X-cut with each leg approximately 1.
While tape and knife adhesion tests are generally regarded as more subjective than their tensile pull-off adhesion test counter parts, the tape and knife adhesion tests can be much more revealing of the true adhesion properties of a coating system. Recently, have seen hubs in service within one year showing heavy signs of spots, blisters, etc due to coatings applied at low temperatures at the construction stage.
Tensile pull-off adhesion is the subject of an article by Melissa Swogger that is also available on the KTA University site. Adhesion is rated based on the scale provided in the ASTM standard. Generally, adhesion ratings of 8 and 10 are considered good, adhesion values of 4 and 6 are considered marginal, and adhesion values of 2 and 0 are considered poor.
Coating Adhesion Testing Using Knife/Tape MethodsKTA University
Never the less, the adhesion is oftentimes considered to be acceptable under these conditions. The adhesion by knife test may provide a more accurate picture of the actual adhesion characteristics.
Coating Adhesion Testing using Knife/Tape Methods
Variations in temperature and humidity can affect the efficacy of the method employed. The shear tests are oftentimes more definitive because they better replicate the way in which coatings fail. Summary of Test Method tions. Adhesion is evaluated qualitatively on a 0 to 10 scale. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters.
Standard – Standard Test Method for Evaluating Adhesion by Knife ASTM D –
However, the subsequent delamination is a result of shear forces. Report Current edition approved May 10, Adhesion testing may be a requirement of a coating specification, or may be used for coating system performance qualification in a laboratory. Knife adhesion tests may be used to assess the bond to the substrate when the astmm adhesion test results revealed a break somewhere higher up in the coating system.
The tip of a knife blade is 6d677 inserted into the intersect of the two incisions and e6677 to attempt to lift the coating from the substrate or an underlying coating. Adhesion is rated on an even number scale between 0 and 10, with 10 having the best adhesion and 0 the worst. The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard.
The values given in parentheses are for information 5. Rate according to Table 1. Both tests are performed by scribing the coating to the substrate with a sharp knife blade in a specific pattern, applying a pressure sensitive tape and then rapidly pulling the tape from the surface.
If the tape adhesion test is required, the chalking should be removed from the area prior to performing the test.
Standard Test Method for Evaluating Adhesion by Knife
After removal of the tape, the amount of coating removed from the substrate or underlying coating is rated. That is, coatings generally do not disbond ast, a substrate or other coating as a result of forces that are exerted perpendicular to the surface.
If you feel that your comments have not received aztm fair hearing you should make your views known to the ASTM Committee on Standards, at the address shown below. In order to be successful a coating system has to have both good tensile and shear adhesion.