Significato e uso
5.1 Many petroleum products and some non-petroleum materials are used as lubricants and the correct operation of the equipment depends on the appropriate viscosity of the liquid used. Inoltre, the viscosity of many petroleum fuels is important for estimating better storage, handling and operating conditions. Perciò, the accurate determination of viscosity is important for many product specifications.

Raggio
1.1 This test method specifies a procedure for determining the kinematic viscosity ν of transparent and opaque liquid petroleum products by measuring the time of a given volume of liquid in a gravity-over-calibrated glass capillary viscometer. The dynamic viscosity η can be obtained by multiplying the kinematic viscosity ν by the density ρ of the liquid.

Nota 1: For measurement of kinematic viscosity and viscosity of asphalt, see also test methods D2170 and D2171.

Nota 2: ISO 3104 corresponds to test method D445-03.

Metodo di prova standard ASTM D445-2018 per la viscosità cinematica di liquidi trasparenti e opachi (Calcolo della viscosità dinamica)

1.2 The results obtained from this test method depend on the behavior of the sample and are intended to be applied to liquids where the shear stress and shear rate are proportional (Newtonian flow behavior). Tuttavia, if the viscosity varies significantly with the shear rate, different results can be obtained from viscometers with different capillary diameters. Procedure and precision values have been included for residual fuel oils, which exhibit non-Newtonian behavior in some cases.

1.3 The test method covers the kinematic viscosity range from 0.2 mm2/s to 300,000 mm2/s (see Table A1.1) at all temperatures (Vedere 6.3 E 6.4). Accuracy is determined only for these materials, kinematic viscosity ranges, and temperatures, as indicated in the footnote in the accuracy section.

1.4 I valori espressi in unità SI sono considerati valori standard. The SI unit used in the kinematic viscosity test method is mm2/s, and the SI unit used in the dynamic viscosity test method is mPa·s. For user reference, 1 mm2/s = 10-6 m2/s = 1 cSt and 1 mPa·s = 1 cP = 0.001 Pa·s.

1.5 Avvertimento – Mercury has been designated by many regulatory agencies as a hazardous substance that can cause serious medical problems. È stato dimostrato che il mercurio o i suoi vapori sono dannosi per la salute e corrosivi per i materiali. Be careful when handling mercury and products containing mercury. Per maggiori informazioni, refer to the applicable Product Safety Data Sheet (Scheda di sicurezza). Local or national laws may prohibit the sale of mercury or mercury-containing products, o entrambi. Users need to determine the legality of the sale in their location.

Metodo di prova standard ASTM D445-2018 per la viscosità cinematica di liquidi trasparenti e opachi (Calcolo della viscosità dinamica)

1.6 Questo standard non è destinato ad affrontare tutti i problemi di sicurezza, se presente, legati al suo utilizzo. È responsabilità degli utenti di questo standard stabilire una sicurezza adeguata, pratiche sanitarie e ambientali e per determinare l'applicabilità delle restrizioni normative prima dell'uso.

1.7 Questo standard internazionale si basa su principi di standardizzazione riconosciuti a livello internazionale stabiliti nella Decisione sui principi per lo sviluppo di standard internazionali, Linee guida e raccomandazioni emesse dal Comitato sugli ostacoli tecnici al commercio dell'Organizzazione mondiale del commercio.