Physical Address
304 North Cardinal St.
Dorchester Center, MA 02124
D2595-22 – Standard Test Method Technical Guide
📐 Scope and Test Principle
ASTM D2595-22 provides a standardized method for determining the evaporation loss of lubricating greases across a wide temperature range. While Test Method D972 is limited to a maximum of 149 °C (300 °F), D2595-22 extends this capability to cover temperatures from 93 °C to 316 °C (200 °F to 600 °F). A lubricating grease, as defined in Terminology D4175, is a semi‑fluid to solid product of a thickener in a liquid lubricant. The thickener forms a two‑phase system, immobilizing the liquid lubricant by surface tension and other physical forces. The dispersion of the thickener can be fibers (such as metallic soaps) or plates or spheres (such as non‑soap thickeners).
The test principle involves exposing a precisely weighed grease sample in an evaporation cell to a controlled heating device. Heated air is passed over the surface of the grease sample for a defined period of 22 hours ± 0.1 hours. The evaporation loss is calculated based on the weight lost by the sample during this process.
⚙️ Test Procedure and Key Parameters
The procedure requires strict adherence to temperature and airflow specifications. The evaporation cell and apparatus must be constructed from materials that can withstand the elevated test temperatures, typically referencing corrosion‑resistant steels such as those specified in ASTM A240/A240M. Temperature measurement relies on instruments conforming to the Guide for Digital Contact Thermometers (ASTM E2877). The test can be performed at any specified temperature agreed upon by the user within the operative range.
⚠️ Safety Warning: This test method operates at temperatures reaching up to 316 °C (600 °F). Users must establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. Standard precautionary measures for handling hot equipment and volatile compounds should be strictly followed (see Section 5.2 of the standard).
The following table summarizes the critical operational parameters for D2595-22 compared to its base method:
| 🎯 Parameter | 📐 D2595-22 Specification |
|---|---|
| Temperature Range | 93 °C to 316 °C (200 °F to 600 °F) |
| Augmenting | D972 (limited to 149 °C / 300 °F) |
| Test Duration | 22 h ± 0.1 h |
| Test Medium | Lubricating Grease |
| Measured Output | Evaporation Loss (mass %) |
📊 Significance of Results and Referenced Standards
The loss of volatile materials from greases can adversely affect their original performance characteristics, such as consistency, lubricity, and oxidation stability. Such volatiles can also be considered contaminants in the environment where the lubricant is used. This test method serves as a critical tool for assessing a lubricant’s suitability for specific high‑temperature uses. However, according to the standard (Section 5.1), a direct correlation between these laboratory results and actual service performance has not been established.
💡 Technical Note: ASTM D2595-22 is specifically intended for greases, augmenting D972 which covers greases and oils but is thermally limited. Always specify the exact test temperature when reporting results, as the test can be performed at any agreed‑upon temperature within the 93 °C to 316 °C range.
The standard references several key ASTM documents for materials and terminology:
| 🟦 Reference | 📏 Title / Purpose |
|---|---|
| A240/A240M | Specification for Chromium and Chromium‑Nickel Stainless Steel Plate, Sheet, and Strip for Pressure Vessels and for General Applications |
| D972 | Test Method for Evaporation Loss of Lubricating Greases and Oils |
| D4175 | Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants |
| E2877 | Guide for Digital Contact Thermometers |
❓ Frequently Asked Questions
🔍 What is the specific temperature range of ASTM D2595-22?
The standard covers evaporation loss testing at temperatures between 93 °C and 316 °C (200 °F and 600 °F).
💡 How does D2595-22 differ from Test Method D972?
D972 is limited to a maximum of 149 °C (300 °F). D2595-22 is specifically designed to augment D972 by extending the testing capability up to 316 °C (600 °F) for lubricating greases.
⚡ What is the required duration for the evaporation test?
The heated air must be passed over the grease sample for exactly 22 hours ± 0.1 hours.
📌 Does a good result in this test guarantee performance in the field?
According to Section 5.1 of the standard, a direct correlation between evaporation loss results from this test method and actual service performance has not been established. It is one of several criteria that should be considered together with service experience.