GB/T 4985-2021Standard test method for needle penetration of petroleum waxes (English PDF)

3.1 Penetration of petroleum wax

The depth to which a standard needle vertically penetrates into a wax specimen under specified conditions, expressed in 1/10 mm.

NOTE: For example, a reading of 85 on the penetrometer dial indicates a penetration value of 85 1/10 mm and a penetration depth of 8.5 mm.

3.2 Penetrometer

An instrument (or device) for determining the consistency or hardness of a solid or semisolid sample by measuring the depth to which a needle or cone of a specified weight penetrates into the sample under a specified gravity.

5.1 Penetrometer

5.1.1 Penetrometer: The schematic diagram is shown in Figure 1. In this document, a standard needle is used to measure the hardness of wax specimens. The total load includes the standard needle, the slide bar and the 50 g weight, a total of 100 g.

5.1.2 Manual penetrometer: It is used to make the standard needle contact the specimen surface and measure the penetration depth of the standard needle into the specimen when the test is completed. When the indicator of the manual penetrometer reads "zero", the needle tip shall be accurately placed on the surface of the wax specimen through the adjustment device. One type of adjustment device is an adjustable test table. The other type is an adjustable needle assembly. Either one is selected. The instrument is equipped with a horizontal adjustment screw and a level to ensure that the slide shaft is in a vertical position. When releasing the loaded standard needle, the standard needle shall fall off without obvious resistance. The scale of the indicator shall be calibrated to 1/10 mm. The scale range shall be not less than 250 1/10 mm.

5.1.3 Automatic penetrometer: used to make the standard needle contact the surface of the specimen.

5.7 Thermometer

It is a precision thermometer for measuring water bath temperature. It is a full immersion type. The scale range is 25°C~55°C. It meets the requirements of GB-71 thermometer specified in GB/T 514-2005.

5.8 Brass plate

The specifications are 63.5 mm ± 1.6 mm in length, 38.0 mm ± 1.6 mm in width, and 6.4 mm ± 1.6 mm in thickness. It is used to support the sample when it is prepared for molding. The plate is placed on an insulating material such as a cork or rubber stopper during the cooling of the sample.

5.9 Reagent

Glycerol aqueous solution (50% by volume).

7.1 Manual penetrometer

7.1.1 Place the head of the manual penetrometer on the edge of the water bath (5.6) and over the porous specimen holder that supports the specimen. A weight may be placed on the base of the penetrometer to balance the head. Adjust the penetrometer and the porous specimen holder in the water bath to a level position.

7.1.2 Ensure that the specimen former and porous specimen holder do not shake during the test. Adjust the water bath surface to at least 25 mm above the upper surface of the specimen. Maintain the test temperature (within ± 0.1°C). Before measuring each sample, measure the temperature of the water bath using the thermometer specified in 5.7.

7.1.3 Add a 50 g weight to the standard needle so that the total mass of the standard needle and its accessories is 100 g ± 0.15 g. Check whether the release device is stuck. The indicator shall be at the "zero" position. Adjust the needle assembly or the test bench according to the different types of adjustment devices. Adjust until the tip of the standard needle almost touches the surface of the specimen. The needle tip is located on a circle at least 3.2 mm from the edge of the specimen former and the four test positions are approximately equally spaced (separated by not less than 12.7 mm). Securely lock the movable components in this position.

7.1.4 Fine-tune the standard needle tip to make it just touch the surface of the wax specimen. Observing the projection of the standard needle tip will help to make accurate adjustments. After confirming that the water bath temperature is within the specified range, release the slide bar and keep it for 5 s±0.1 s. Use an automatic timing device or a stopwatch with an accuracy of 0.1 s to time. Gently press down the indicator rod until it is supported by the slide bar. Read the needle penetration value from the indicator dial.

7.1.5 Carry out the measurement of the remaining three test positions according to the requirements of 7.1.3 and 7.1.4. Before each measurement, wipe carefully along the needle tip with a clean dry cloth to remove all attached wax samples.

7.2 Automatic penetrometer

7.2.1 Place the adjustable needle assembly of the automatic penetrometer above the water bath (5.6) and above the porous specimen holder supporting the specimen. Proceed as in 7.1.2.

7.2.2 Set up the penetrometer according to the instrument manual and test the penetration value according to the requirements in 7.1.3 ~ 7.1.5.