1. What Is a Flat Gasket?
A flat gasket is a static sealing element with a flat cross-section, installed between two mating flat surfaces. Sealing is achieved by compressing the gasket using bolts or clamping force.
Flat gaskets are the most widely used, simplest, and most cost-effective sealing components.
2. Core Functions of Flat Gaskets
1) Static Sealing
- Prevents leakage of liquids or gases
- Used in non-moving, static sealing applications
2) Tolerance Compensation
- Fills microscopic surface irregularities
- Compensates for machining and assembly tolerances
3) Vibration Damping
- Prevents metal-to-metal contact
- Reduces vibration and noise
3. Typical Applications
|
Industry |
Application |
|
Pipe flanges |
Water, steam, oil, gas |
|
Equipment housings |
Pumps, valves, gearboxes |
|
Home appliances |
Washing machines, water heaters |
|
Automotive |
Oil pans, transmissions |
|
Industrial machinery |
Compressors, hydraulic units |
4. Common Flat Gasket Designs
- Shapes: Round, square, rectangular, custom profiles
- Coverage: Ring-type or full-face gaskets
5. Materials and Selection Guidelines
Rubber Flat Gaskets
|
Material |
Suitable Media |
Temperature Range |
Features |
|
EPDM |
Water, steam, mild chemicals |
-40 ~ +150°C |
Preferred for water systems |
|
NBR |
Oils and fuels |
-30 ~ +120°C |
Oil resistant |
|
FKM (Viton) |
Chemicals, high-temp oils |
-20 ~ +200°C |
High performance |
|
CR (Neoprene) |
Seawater, refrigerants |
-30 ~ +100°C |
Weather resistant |
|
Silicone |
Food, medical |
-60 ~ +200°C |
Clean and inert |
Rubber flat gaskets offer excellent elasticity and high assembly tolerance.
6. Key Performance Indicators
|
Property |
Description |
|
Hardness |
Typically 50–80 Shore A |
|
Compression set |
Long-term sealing ability |
|
Stress relaxation (CSR) |
Service life |
|
Media resistance |
Swelling & softening control |
|
Aging resistance |
Heat, ozone, UV |
7. Common Failure Modes
|
Failure |
Root Cause |
|
Leakage after use |
Excessive compression set |
|
Gasket extrusion |
Too soft or too thick |
|
Hardening & cracking |
Inadequate heat resistance |
|
Surface sticking |
Additive migration or formulation issues |