1.Types and Materials
(1) Metal O-Ring
- Materials: Stainless steel (304/316), Inconel 600/625, Hastelloy C-276, titanium alloys, etc.
- Temperature Resistance:
- Stainless steel: Up to 800°C (short-term to 1000°C in inert gas/vacuum).
- Inconel/Hastelloy: 1000~1200°C (under inert gas protection).
- Pressure Resistance:
- Static sealing: 50~300 MPa (depends on design).
- Dynamic sealing: Typically below 100 MPa.
(2) Spiral Wound Gasket
- Structure: Metal strips (e.g., 304/316, titanium) + non-metal filler (graphite, PTFE).
- Temperature Resistance:
- Graphite filler: -200°C ~ +600°C (450°C max in oxidizing environments).
- PTFE filler: -260°C ~ +260°C.
- Pure metal strips: ≤800°C.
- Pressure Resistance:
- Standard: ≤25 MPa (ASME B16.20).
- High-pressure design: ≤42 MPa.
(3) 八角垫/椭圆垫 | Ring Joint Gasket (RTJ)
- Materials: Soft iron, stainless steel, Monel, Inconel.
- Temperature Resistance:
- Soft iron: ≤540°C.
- Stainless steel/Ni-alloys: ≤800°C.
- Pressure Resistance:
- API 6A: 69~138 MPa (oil/gas wellheads).
- Flange connections: 20~100 MPa.
2. Key Factors
- Environment: Oxidative/corrosive media reduce performance.
- Sealing surface design: Flange roughness, flatness, and bolt preload.
- Thermal cycling: Frequent changes cause fatigue.
- Standards: ASME B16.20, API 6A define limits.