ASTM D2319 Standard Test Method for Softening Point of Pitch (Cube-in-Air Method)
3. Summary of Test Method
3.1 Two cubes ofpitch, supported on wire hooks, are heated in a standardized air oven at a linear rate. The softening point is the mean of the temperatures at which the cubes sag downwards a distance of 60 mm [2.4 in.].
4. Significance and Use
4.1 Pitch does not go through a solid-liquid phase change when heated and therefore does not have a true melting point. As the temperature is raised, pitch softens and becomes less viscous. The softening point is arbitrarily defined and must be determined by a closely controlled method that must be carefully followed if test results are to be reproducible.
4.2 This test method is useful in determining the consistency of pitch as one element in establishing the uniformity of shipments and sources of supply.
