D2983-23 – Standard Test Method Technical Guide

ASTM D2983-23 specifies a test method for determining low-temperature viscosity of automatic transmission fluids, hydraulic fluids, and lubricants using rotational viscometers. Covering a viscosity range from 300 mPa·s to 900 000 mPa·s, this standard incorporates four distinct procedures for sample cooling and viscosity measurement. The test method is essential for assessing fluid performance at low temperatures and is widely used in the lubricant industry.

📐 Test Scope and Procedures

This test method is applicable for low-shear-rate viscosity measurement of various fluids at low temperatures. It includes four procedures. Procedure A uses an air bath for cooling samples before measurement. Procedure B employs a mechanically refrigerated programmable liquid bath. Procedure C uses a simulated air cell (SimAir) with a constant temperature liquid bath. Procedure D automates the process with a thermoelectrically heated and cooled chamber and a programmable rotational viscometer. The standard was previously titled “Low-Temperature Viscosity of Lubricants Measured by Brookfield Viscometer,” and results are often referred to as Brookfield viscosity.

⚙️ Viscometer Configuration and Measurement

The test method requires rotational viscometers with appropriate torque range and specific spindles for low-shear-rate measurement. Viscosity is reported in milliPascal-seconds (mPa·s), where 1 cP equals 1 mPa·s. The method covers a broad viscosity range, with precision studies conducted at temperatures from –12 °C to –55 °C, depending on the procedure. The viscometer must be capable of measuring within the specified viscosity range of 300 mPa·s to 900 000 mPa·s.

📊 Precision and Viscosity Data

Precision studies for Procedures A, B, and C cover viscosities from 300 mPa·s to 170 000 mPa·s at test temperatures of –12 °C, –26 °C, and –40 °C. Additional data in Appendix X5 includes –55 °C test temperature and samples with viscosities greater than 500 000 mPa·s. For Procedure D, precision data spans from 6 400 mPa·s to 256 000 mPa·s at –26 °C and –40 °C.