ASTM D341 Standard Practice for Viscosity-Temperature Charts
ASTM D341 Standard Practice for Viscosity-Temperature Charts for Liquid Petroleum Products
1. Scope
1.1 This practice covers kinematic viscosity-temperature charts (see Figs. 1 and 2), which are a convenient means to ascertain the kinematic viscosity of a petroleum oil or liquid hydrocarbon at any temperature within a limited range, provided that the kinematic viscosities at two temperatures are known.
1.2 The charts are designed to permit petroleum oil kinematic viscosity-temperature data to plot as a straight line. The charts here presented provide a significant improvement in linearity over the charts previously available under Method D341-43. This increases the reliability of extrapolation to higher temperatures.
1.3 The values provided in SI units are to be regarded as standard. The values given in parentheses are provided for information only.
2. Referenced Documents
2.1 ASTM Standards:
D445 Test Method for Kinematic Viscosity of Transparent and Opaque Liquids (and Calculation of Dynamic Viscosity)
2.2 ASTM Adjuncts:
Viscosity-Temperature Charts 1-7
3. Technical Hazard
3.1 Warning - The charts should be used only in that range in which the hydrocarbon or petroleum fluids are homogeneous liquids. The suggested range is thus between the cloud point at low temperatures and the initial boiling point at higher temperatures. The charts provide improved linearity in both low kinematic viscosity and at temperatures up to 340°C (approximately 650°F) or higher. Some high-boiling point materials can show a small deviation from a straight line as low as 280°C (approximately 550°F), depending on the individual sample or accuracy of the data. Reliable data can be usefully plotted in the high temperature region even if it does exhibit some curvature. Extrapolations into such regions from lower temperatures will lack accuracy, however. Experimental data taken below the cloud point or temperature of crystal growth will generally not be of reliable repeatability for interpolation or extrapolation on the charts. It should also be emphasized that fluids other than hydrocarbons will usually not plot as a straight line on these charts.
