ASTM D5018 Standard Test Method for Shear Viscosity of Coal-Tar and Petroleum Pitches
7. Safety Hazards
7.1 Fumes of hot pitch or solvents, or both, should be removed from all working areas by means of proper hoods. The working area should be kept free of sparks and flames. Quinoline fumes should not be inhaled, and prolonged contact with skin should be avoided. Toluene is toxic and flammable.
8. Bulk Sampling
8.1 Take samples from shipments in accordance with Practice D4296. Samples shall be free of foreign substances. Thoroughly mix the sample immediately before removing a representative portion for the determination or for dehydration.
9. Sample Preparation
9.1 Ensure sample is dry; if there is visible moisture, dehydrate at 50 °C in a forced-air or vacuum oven until dry, but no longer than 2 h. (Experience has shown that drying at temperatures in excess of 50 °C increases the SP and viscosity of the pitch.)
9.2 Crush dry lumps of pitch to a size of 6 mm to 12 mm.
10. Charging Sample Cup
10.1 In a suitable container, or the sample cup, melt pitch with occasional stirring. Overheating of sample must be avoided as loss of volatiles may affect viscosity. (Maximum temperature should not exceed 50 °C above SP. As a guide, the surface temperature of the hot plate surface should not exceed 200 °C.)
10.2 Place rotor in cup and preheat both to approximately the first test temperature.
10.3 Remove rotor and transfer required amount of pitch to the level specified by the manufacturer.
10.4 Re-insert rotor, check that rotor is immersed to specified depth, and install insulating cover.
11. Viscometer Calibration
11.1 This step, required only occasionally, is designed to establish that the temperature and viscosity indicated by the appropriate measuring devices are in agreement with known standards.
11.2 Equipment is to be properly leveled and installed in accordance with manufacturer's instructions.
11.3 Use the ASTM thermometer (applying the appropriate stem correction) to correlate pitch temperature (in cup) to temperature controller/indicator. Test temperature is considered to be the actual pitch temperature and not the temperature indicated on the controller.
11.4 Calibrate viscometer using calibration fluids (see Test Method E2975).
11.4.1 Use high- and low-temperature fluids; see 5.5.
11.4.2 Calibrate each rotor/cup combination and use them as a paired set.
