ASTM D1321 for needle penetration of petroleum waxes
ASTM D1321 standard test method for needle penetration of petroleum waxes
8. Procedure
8.1 Reverse the penetrometer base and place the penetrometer head over the edge of the water bath and above the perforated test shelf used for supporting the specimen. It may be necessary to place a weight on the base of the penetrometer to counterbalance the head (Note 5). Level the penetrometer and the perforated shelf in the water bath.
NOTE 4 - Alternatively, the penetrometer may be placed in the water bath. Likewise, a small bath may be placed on the penetrometer stand provided the test temperature (within 0.1°C (more or less 0.2°F)) and the required water circulation above and below the test specimen are maintained and provided further that the temperature of the small bath is measured immediately before testing each specimen using the thermometer specified in 6.7. Emergent stem corrections shall be applied when the correction equals or exceeds 0.05°C (0.1°F). One of the above alternatives will be required if the penetrometer is the adjustable table type.
8.2 Place the specimen container on the perforated test shelf with the smooth wax surface that had contacted the brass plate at the top. Make certain that the container or test shelf cannot teeter during testing. Adjust the water level so that it is at least 25 mm (1 in.) above the top surface of the specimen and maintain it at the test temperature.
NOTE 5 - The test may be performed at any temperature in the range from 25 to 55°C (77 to 130°F). Temperatures 25, 35, 45, or 50°C (77, 95, 113, or 122°F) normally are used.
8.3 Place a 50-g weight above the penetrometer needle, making a total load of 100 more or less 0.15 g for the needle and all attachments. Observe that the release mechanism does not drag on the shaft and that the indicator on the scale is in the "zero" position. Adjust either the indicator assembly or the table, depending upon the type of instrument, until the tip of the needle nearly touches the surface of the specimen. Securely lock the movable assembly in this position.
8.4 Then, by means of the slow-motion adjustment, bring the needle tip to just touch the surface of the specimen, watching the reflection of the needle tip as an aid to accurate setting. After ensuring the bath temperature is within the proper specifications, release the needle shaft and hold it free for 5.0 more or less 0.1 s, timing this interval automatically or with a stop watch graduated to 0.1 s. Then gently depress the indicator shaft until it is stopped by the needle shaft and read the penetration from the indicator scale.
8.5 Make four tests at points about equally spaced (not less than 12.7 mm (1/2 in.) apart) on a circumference at least 3.2 mm (1/8 in.) from the side of the container. Before each test, wipe the needle carefully toward its point with a clean, dry cloth to remove all adhering wax, position the needle as described in 8.4, and proceed with the test.
