Steel Pipe Gasket Selection for High-Temperature Service: Complete Engineering Guide 2026
In the global steel and metal supply industry, technical knowledge is the foundation of every successful procurement decision. This comprehensive guide covers essential engineering principles, industry standards, and practical considerations that every professional in the metallurgical supply chain should understand. As a leading supplier, CoreMetal Steel (Xi’an Coremetal Steel Co., Ltd.) provides this technical reference to support informed material selection and project specification.
Gasket Function and High-Temperature Challenges
Gaskets in steel pipe flange connections serve the critical function of creating a static seal between two flange faces, preventing process fluid leakage under operating conditions. High-temperature service presents unique challenges for gasket performance:
- Thermal degradation: Elastomeric and non-metallic gasket materials lose elasticity, decompose, or oxidize at elevated temperatures
- Creep relaxation: All gasket materials undergo creep under bolt load at high temperatures, reducing the sealing stress over time
- Thermal cycling: Repeated heating and cooling causes differential expansion between flanges, bolts, and gaskets, potentially breaking the seal
- Oxidation: Gasket materials exposed to high-temperature air or oxidizing atmospheres degrade through oxidation reactions
- Bolt load changes: Differential thermal expansion of bolts and flanges changes the available clamping force at temperature
Proper gasket selection for high-temperature service requires understanding the complete set of operating conditions and the performance characteristics of each gasket type.
Gasket Types for High-Temperature Applications
| Gasket Type | Max Temperature | Max Pressure | Best Applications | Limitations |
|---|---|---|---|---|
| Spiral Wound (SW) | Up to 1000 C (with graphite filler) | Up to 250 bar | Process piping, refineries, power plants | Requires controlled bolt loading; can blow out |
| Flexible Graphite (die-formed) | Up to 500 C (oxidizing), 3000 C (inert) | Up to 250 bar | High-temperature chemical service | Low mechanical strength; requires good flange condition |
| Metal Jacketed | Up to 900 C (with soft filler) | Up to 150 bar | Heat exchangers, moderate-pressure high-temp | Limited thermal cycling capability |
| Ring Joint (RTJ) | Up to 1000 C+ | Up to 1500+ bar | Oil and gas, high-pressure high-temperature | Requires RTJ flange faces; expensive |
| Corrugated Metal | Up to 800 C | Up to 100 bar | Exhaust systems, low-pressure high-temp | Limited sealing capability on imperfect flanges |
| Kammprofile (Camprofile) | Up to 800 C (with graphite) | Up to 400 bar | Process plants with thermal cycling | Higher cost than spiral wound |
Spiral Wound Gasket Selection Details
Spiral wound gaskets (SWGs) are the most widely used gasket type for high-temperature steel pipe flange connections. They consist of alternating layers of metal winding strip and soft filler material, wound in a V-shaped spiral.
Metal Winding Material Selection
| Winding Material | Max Temperature (C) | Service Environment |
|---|---|---|
| 304 Stainless Steel | 800 | General purpose, water, steam, air |
| 316L Stainless Steel | 800 | Chloride-containing, marine, chemical |
| 321 Stainless Steel | 800 | High-temperature oxidizing service |
| Inconel 625 | 1000 | Severe corrosive, high-temperature |
| Monel 400 | 700 | Hydrofluoric acid, seawater |
| Titanium | 600 | Chlorides, oxidizing acids |
Filler Material Selection
| Filler Material | Max Temperature (C) | Service Notes |
|---|---|---|
| Flexible Graphite | 500 (oxidizing) / 3000 (inert) | Most versatile; attacks aluminum in some conditions |
| PTFE | 260 | Excellent chemical resistance; limited to low temperatures |
| Ceramic Fiber | 1000+ | Extreme temperature; brittle handling |
| MICA | 900 | High-temperature oxidizing service |
Ring Joint Gaskets for Extreme Conditions
Ring Type Joint (RTJ) gaskets provide metal-to-metal sealing for the most demanding high-temperature, high-pressure applications. They are used exclusively with RTJ flange faces (per ASME B16.5).
RTJ Gasket Types
- Oval cross-section (Type R): Traditional design, seats in the full flange groove. Limited to pressures below the flange rating. Can be reused if undamaged
- Octagonal cross-section (Type R): Higher sealing stress capability than oval. Better for high-pressure applications
- Pressure energized (Type RX): Modified profile that uses internal pressure to increase sealing force. Retrofittable to standard RTJ grooves
- Self-sealing (Type BX): Advanced design with radial seal and pressure-energized sealing. Used in the most critical subsea and HPHT applications
RTJ Gasket Materials
| Material | API Ring Number | Max Temperature (C) | Applications |
|---|---|---|---|
| Soft Iron | R/BX/RX | 700 | General oil and gas |
| Carbon Steel | R/BX/RX | 600 | Non-corrosive hydrocarbon service |
| 304 SS (F304) | R/BX/RX | 800 | Corrosive process service |
| 316 SS (F316) | R/BX/RX | 800 | Chloride-containing service |
| Inconel 625 (F625) | R/BX/RX | 1000 | Severe sour service, HPHT |
Installation and Quality Assurance
Proper gasket installation is critical for achieving reliable high-temperature sealing:
- Flange face inspection: Verify flange face finish (typically 125-250 AARH for SWGs, 32-63 AARH for RTJ). Check for scratches, radial tool marks, pitting, or warpage
- Gasket handling: Avoid damaging the sealing surfaces. Store gaskets in clean, dry conditions. Inspect for winding separation, filler extrusion, or physical damage before installation
- Bolt lubrication: Apply appropriate anti-seize or lubricant to bolt threads and nut bearing surfaces. Use the same lubricant for all bolts to ensure uniform friction
- Bolt tightening sequence: Follow the star-pattern or cross-tightening sequence specified in ASME PCC-1. Use the four-pass method: snug, 30%, 60%, 100% of target torque
- Hot bolting: For high-temperature service, consider hot torquing (retightening at operating temperature) to compensate for thermal relaxation
- Leak testing: Perform leak testing (hydrostatic, pneumatic, or helium sniff) after installation and after initial thermal cycling
For flanges, gaskets, and bolting in high-temperature piping systems, CoreMetal Steel supplies certified materials in all standard and special sizes per ASME B16.5, B16.47, and API 6A specifications.
Why Choose CoreMetal Steel as Your Trusted Supplier
Xi’an Coremetal Steel Co., Ltd. (CoreMetal Steel) is a professional steel and metal products supplier with ISO 9001 certification, serving clients in over 60 countries worldwide. Our product range covers carbon steel, stainless steel, alloy steel, galvanized steel, aluminum, copper, titanium, and nickel alloy products in various forms including plates, sheets, coils, pipes, tubes, bars, fittings, and flanges.
Our competitive advantages include:
- Certified Quality: ISO 9001 certified with full Mill Test Certificates (MTC) provided for every shipment
- Comprehensive Inventory: Extensive stock of standard and specialized products for immediate delivery
- Global Logistics: Efficient shipping from major Chinese ports with seaworthy export packaging
- Technical Support: Professional team available for material selection guidance and specification consultation
- Competitive Pricing: Direct mill-source pricing with transparent cost structures
For technical consultations, material inquiries, or competitive quotations, contact our team:
Contact: Tracy
Email: tracy@coremetalsteel.com
Phone/WhatsApp: +86 18291910632
We welcome OEM/ODM orders and look forward to establishing long-term partnerships with clients worldwide. Request your quote today and experience the CoreMetal difference in quality, service, and value.