## Typical Tensile & Elongation Values
| Material | Tensile Strength | Elongation at Break | Notes |
| — | — | — | — |
| NR | 20–25 MPa | 500–650 % | Outstanding resilience, low cost |
| NBR | 12–18 MPa | 250–450 % | Balances strength with oil resistance |
| HNBR | 15–22 MPa | 200–350 % | Higher tear strength for dynamic service |
| EPDM | 10–20 MPa | 300–500 % | Good for water/steam |
| Silicone | 6–12 MPa | 300–700 % | Lower strength, high flexibility |
| FKM | 12–18 MPa | 150–300 % | Maintains strength at high temperature |
| PTFE | 20–35 MPa | <100 % | Rigid; requires energisers | ## Design Implications - **Installation** – ensure elongation allows stretch over hardware without exceeding 75% of elongation-at-break. - **Dynamic loading** – higher tensile/tear strength reduces risk of nibbling in reciprocating applications. - **Temperature** – tensile strength decreases with heat; review data at operating temperature. - **Compounding** – fillers and cure systems modify tensile properties; verify specification for each compound. - **Quality control** – monitor tensile retention post aging/immersion to detect degradation. ## Testing Practices - ASTM D412 (die C or die D) for tensile/elongation. - Test both pre- and post-aging/immersion samples. - Record stress-strain curves to evaluate modulus (important for compression force). - For PTFE and thermoplastics, use appropriate standards (ASTM D638). - Maintain calibration of tensile testers and ensure consistent sample preparation. ## Related Resources - [Material Comparison Table](/materials/rubber-materials-classification-performance-comparison/) - [Maintenance Guide](/materials/industrial-rubber-seal-selection-maintenance-guide/) - [Design Services](/services/design-services/) – apply tensile data to FEA and safety factor calculations.