Physical Address
304 North Cardinal St.
Dorchester Center, MA 02124
D5662-23 – Standard Test Method Technical Guide
📐 Specimen Geometry and Elastomer Materials
This test method uses Die C dumbbell specimens as specified in Test Methods D412. Three specific elastomer formulations are tested: nitrile (NBR), polyacrylate (ACM), and fluoroelastomer (FKM) oil seal materials. These represent the typical polymers employed in automotive gear oil seals.
| 🟦 Elastomer Type | 📏 Designation | 🎯 Typical Application |
|---|---|---|
| Nitrile | NBR | General mineral oil seals |
| Polyacrylate | ACM | High‑temperature seals |
| Fluoroelastomer | FKM | Chemically resistant seals |
⚙️ Test Procedure and Measured Properties
A modified version of Test Method D471 is used. Non‑reference oils are placed in a heated oil bath together with reference oils that monitor test consistency. Three key elastomer changes are measured before and after immersion:
| 🔬 Property | 📏 Unit | ⚡ Indication |
|---|---|---|
| Percent Ultimate Elongation Change | % | Loss of flexibility |
| Durometer Hardness Change (Type A) | Shore A points | Surface hardening/softening |
| Percent Volume Change | % | Swelling or shrinkage |
Percent ultimate elongation change is the stretch at rupture of the oil‑aged dumbbell minus that of the untested dumbbell, divided by the untested value, multiplied by 100. Reference oil results validate the test batch.
💡 Reference oils are essential for determining test consistency. If their values shift markedly, the entire oil bath condition must be investigated before approving non‑reference oil data.
📊 Referenced Standards and Quality Practices
The standard also cites D5704 (thermal/oxidative stability), D5760 (manual transmission lubricant performance), E29 (rounding significant digits), and SAE J2360 (military gear lubricants). All measured values should be reported alongside reference oil results to ensure traceability.
⚠️ Section 1.4 requires users to establish appropriate safety, health, and environmental practices and to follow all applicable regulatory limits before handling gear oils and elastomers.
❓ Frequently Asked Questions
🔍 Why are reference oils required?
They are run in the same oil bath to measure consistency between tests. A change in reference oil data flags potential problems with the test procedure, equipment, or bath contamination.
💡 How is percent ultimate elongation change computed?
According to the standard, it is (rupture stretch of oil‑aged dumbbell − rupture stretch of untested dumbbell) ÷ rupture stretch of untested dumbbell × 100.
⚡ What does durometer hardness change indicate?
Type A hardness change reveals surface modification: an increase implies hardening (crosslinking or oil loss), a decrease implies swelling or plasticization of the seal material.
📌 Which elastomers are specified in D5662‑23?
The method covers nitrile (NBR), polyacrylate (ACM), and fluoroelastomer (FKM) oil seal compounds, which are common in automotive gear oil systems.