ASTM D4366-16(R2021) pdf free download

ASTM D4366-16(R2021) pdf free download.Standard Test Methods for Hardness of Organic Coatings by Pendulum Damping Tests
1. Scope
1.1 These test methods cover the use of pendulum damping testers in the determination ofhardness oforganic coatings that have been applied to acceptably plane rigid surfaces, such as a metal or glass panel. 1.2 Two test methods based on different pendulum types are covered as follows: 1.2.1 Test Method A—König Pendulum Hardness Test. 1.2.2 Test Method B—Persoz Pendulum Hardness Test. 1.3 This standard is similar in content (but not technically equivalent) to ISO 1522. 1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.5 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 appro- priate safety, health, and environmental practices and deter- mine the applicability ofregulatory limitations prior to use. 1.6 This international standard was developed in accor- dance with internationally recognized principles on standard- ization established in the Decision on Principles for the Development of International Standards, Guides and Recom- mendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
4. Summary of Test Methods
4.1 A pendulum resting on a coating surface is set into oscillation (rocking) and the time for the oscillation amplitude to decrease by a specified amount measured. The damping time is influenced by a combination of physical properties, amongst hardness, elasticity, coefficient of friction and shore of the sample under test. The damping time decreases with the decrease of hardness or an increase of elasticity or coefficient of friction.
5. Significance and Use
5.1 The pendulum damping test has been found to have good sensitivity in detecting differences in coating hardness, where hardness is defined as resistance to deformation. 5.2 The two procedures given in these test methods embody the principle that the amplitude of oscillation of a pendulum touching a surface decreases more rapidly the softer the surface. However, these test methods differ in respect to pendulum dimensions, and period and amplitude ofoscillation. 5.3 In general, the damping time of the König pendulum is approximately half that of the Persoz pendulum. 5.4 The Persoz pendulum has a greater degree of discrimi- nation than the König for measuring the hardness of soft coatings, but it may not be as suitable for testing hard, slippery films because of its tendency to skid on surfaces with a low coefficient of friction. 5.5 The interaction between the pendulum and the paint film is complex, depending on both elastic and viscoelastic properties, and it may not be possible to establish a precise relationship between the two types of pendulum tests.
7. Calibration
7.1 Check the alignment of the pendulum and panel table as follows: 7.1.1 Place the polished glass panel on the panel table and gently bring the pendulum to rest on the surface of the glass. Be sure the pendulum oscillates freely. 7.1.2 Place a spirit level on the glass panel surface. Level the glass panel by means of the adjusting procedure of the instrument. 7.1.3 Clean the glass panel by wiping with a soft, lintless cloth wetted with the solvent mixture specified in Practice D3891. 7.1.4 Clean the fulcrum balls by wiping with a soft tissue wetted with solvent, leaving no residue. Leave the pendulum in ambient conditions and then bring it to rest on the glass panel. 7.1.5 Check the position of the pendulum pointer relative to the scale. With the pendulum at rest, its pointer should indicate zero on the scale. If the pointer does not indicate zero, check the leveling of the pendulum tester and the fairness of the pendulum. 7.2 Check the duration of the pendulum swing on a glass panel. 7.2.1 Deflect the pendulum through 6°, release it and simultaneously start a stopwatch or other timing device. 7.2.2 Determine whether the oscillation period of the pen- dulum falls within 1.40 6 00.2 s over a minimum of 100 swings. 7.2.3 If the measured time is less than specified and the pendulum did not skid, move the weight on the pendulum rod upward. If the measured time is more than specified, move the weight downward. Continue adjustments until the specified time is obtained. If the time cannot be obtained, the instrument should be judged faulty and be repaired.