ASTM D6200 Determination of Cooling Characteristics of Quench Oils
ASTM D6200 Standard Test Method for Determination of Cooling Characteristics of Quench Oils by Cooling Curve Analysis
13. Procedure
13.1 Place the probe in the preheated furnace. Bring the probe temperature to the required temperature of 845 to 855°C, (1500 to 1575°F) and soak at this temperature for at least 2 min.
13.2 Transfer the probe to the center of the quench oil sample activating the data collection equipment at the same time. (Warning - see Note 6).
NOTE 6 - Warning: Electric resistance type furnaces may have to be turned off prior to the transfer from the furnaces to the sample when interference with the data collection device is noted.
13.3 Hold the probe assembly without movement, with the mechanical transfer device or a holding fixture.
13.4 When the temperature of the probe has reached 200°C (392°F) or the desired lower temperature, remove it from the oil and clean as described in 9.1.
13.5 Run test in duplicate for reproducibility verification, using the same probe and the same sample of the oil returned to the same temperature prior to the start of the test. The final data that is reported may be averaged to produce the final cooling curve data or the results from both runs may be reported individually. Duplicate testing is not required when the cooling curves for oil being tested are essentially the same as that curve to which the test cooling curve is being compared.
14. Interpretation of Results
14.1 Cooling Curves - Cooling curves and cooling rate curves are obtained for comparison reasons, that is, the oil compared to another oil, a control sample, or previously recorded curves. The test may show the effect of oxidation, the presence of additives and their concentrations, or contamination on the cooling characteristics of a quenching oil. Changes in a quench oil's chemical or physical properties causes changes in its's heat extraction capabilities; either speeding up or slowing down part or all of the curve. See Fig. 1.
