Industrial sealing applications often operate under demanding temperatures, pressures, and chemical environments where gasket material selection directly impacts reliability and safety. While many buyers understand the benefits of stainless steel spiral wound gaskets, selecting the appropriate stainless-steel grade remains a common challenge.
Should you choose SS304 or SS316? When is SS321 preferred? Does SS347 offer advantages in high-temperature service? Understanding these differences can help engineers, procurement teams, and maintenance professionals avoid premature gasket failures, corrosion-related issues, and unnecessary maintenance costs.
This guide explains the construction of stainless steel spiral wound gaskets, compares SS304, SS316, SS321, and SS347 winding materials, discusses filler options, and provides practical selection guidance for various industrial applications.
What Are Stainless Steel Spiral Wound Gaskets?
A spiral wound gasket is a semi-metallic sealing solution manufactured by winding a pre-formed metal strip together with a soft filler material in alternating layers.
This construction combines the strength of metal with the sealing performance of compressible fillers, making spiral wound gaskets suitable for high-pressure and high-temperature flange connections.
Spiral wound gaskets are widely used in refineries, petrochemical plants, chemical processing facilities, pressure vessels, and piping systems. IGP Engineers manufactures spiral wound gaskets with various winding metals and filler combinations to suit diverse operating conditions.
The metal winding provides structural integrity and recovery characteristics, while the filler material fills flange imperfections and helps create a leak-tight seal under varying operating conditions.
Components of a Spiral Wound Gasket
A typical stainless steel gasket consists of:
- Metal winding strip
- Soft filler material
- Inner ring (optional or mandatory depending on service)
- Outer centering ring
The combination of these components determines the gasket’s ability to withstand temperature, pressure, chemical exposure, and thermal cycling.
Understanding Spiral Wound Gasket Materials
The most important element in a spiral wound gasket material selection process is the winding metal.
IGP Engineers offers multiple winding materials, including SS304, SS316, SS321, and SS347 stainless steels, allowing users to match gasket performance with process requirements.
SS304 Spiral Wound Gasket
The SS304 spiral wound gasket is one of the most commonly specified industrial sealing solutions. SS304 offers good corrosion resistance, excellent mechanical strength, and cost-effective performance across a broad range of industrial services. Because of its balanced characteristics, SS304 is often selected for:
- General industrial piping
- Water systems
- Steam services
- Utility applications
- Process equipment operating under moderate conditions
A SS304 spiral wound gasket is typically considered when process media are not highly corrosive and chloride exposure is limited.
Advantages of SS304
- Cost-effective material choice
- Good oxidation resistance
- Suitable for many industrial environments
- Widely available
SS316 Spiral Wound Gasket
The SS316 spiral wound gasket contains molybdenum, which significantly improves resistance to corrosion, particularly in chloride-containing environments.
Industries dealing with aggressive chemicals, marine atmospheres, and corrosive process fluids frequently choose SS316 due to its superior corrosion resistance. Common applications include:
- Chemical processing plants
- Offshore facilities
- Marine environments
- Petrochemical operations
- Water treatment systems
A SS316 spiral wound gasket is often selected whenever corrosion resistance is a primary concern.
Advantages of SS316
- Enhanced resistance to chlorides
- Improved pitting resistance
- Better performance in corrosive media
- Suitable for demanding process environments
SS321 Spiral Wound Gasket
The SS321 spiral wound gasket is a titanium-stabilized stainless steel variant specifically designed for elevated temperature service.
Titanium stabilization helps minimize carbide precipitation during prolonged exposure to high temperatures. This characteristic makes SS321 particularly suitable for applications involving thermal cycling and continuous heat exposure.
Typical applications include:
- Heat exchangers
- Exhaust systems
- High-temperature process equipment
- Furnace-related applications
- Thermal processing industries
Advantages of SS321
- Excellent high-temperature stability
- Improved thermal cycling resistance
- Reduced risk of intergranular corrosion
- Suitable for prolonged elevated-temperature service
When temperature becomes the dominant selection factor, a SS321 spiral wound gasket is often considered a reliable solution.
SS347 Spiral Wound Gasket
The SS347 spiral wound gasket is stabilized with niobium (columbium), providing excellent resistance to intergranular corrosion and elevated-temperature degradation.
Like SS321, SS347 is frequently used in high-temperature applications but may be preferred in specific process conditions where long-term thermal stability is required. Industries commonly considering SS347 include:
- Power generation
- Refining
- Petrochemical processing
- High-temperature reactors
- Pressure vessel applications
Advantages of SS347
- Strong resistance to sensitization
- Excellent thermal stability
- Reliable performance at elevated temperatures
- Suitable for severe industrial environments
For demanding heat-intensive services, a SS347 spiral wound gasket can provide long-term sealing reliability.
Stainless Steel Grade for Spiral Wound Gaskets
| Filler Material | Temperature Range |
| Flexible Graphite | 200–454°C |
| High-Temperature Graphite | 200–600°C |
| Vermiculite | 200–1000°C |
| Phlogopite | 200–1000°C |
| High-Temperature Ceramic | Up to 1300°C |
Note: The appropriate stainless-steel grade and gasket configuration depend on the application’s operating temperature, pressure, process media, flange design, corrosion conditions, and applicable standards.
How Temperature Affects Material Selection
Temperature is one of the most important factors when selecting stainless steel spiral wound gaskets.
Moderate Temperature Service
For general industrial temperatures, SS304 and SS316 frequently provide dependable sealing performance.
Elevated Temperature Service
Applications involving continuous high temperatures often benefit from SS321 or SS347 because of their stabilized microstructure and improved resistance to thermal degradation.
Thermal Cycling Conditions
Equipment that repeatedly heats and cools can place additional stress on gasket materials. SS321 and SS347 are commonly preferred where thermal cycling is significant because they maintain structural integrity more effectively under such conditions.
How Corrosion Influences Material Selection
Selecting the wrong winding material can lead to reduced service life and unexpected maintenance costs.
General Industrial Media
SS304 remains a practical option for many non-aggressive industrial services.
Chemical Processing Environments
A corrosion resistant gasket becomes essential when handling aggressive chemicals. In such situations, SS316 is often preferred because of its improved resistance to chemical attack.
Marine and Chloride Exposure
Chloride-containing environments increase the risk of pitting corrosion. SS316 typically provides better protection compared to SS304, SS321, or SS347.
Need Help Choosing the Right Material?
Selecting the correct spiral wound gasket requires evaluating operating temperature and pressure, chemical compatibility, flange design, and maintenance requirements. Understanding the different types of spiral wound gaskets and their configurations can also help you choose the right gasket for your application.
IGP Engineers manufactures spiral wound gaskets in SS304, SS316, SS321, SS347, and other specialty alloys, helping customers identify suitable sealing solutions for challenging industrial applications.
Understanding Filler Materials
While the winding metal receives significant attention, filler selection is equally important. IGP Engineers offers several filler materials, including graphite, PTFE, vermiculite, phlogopite, ceramic, and non-asbestos options.
1. Graphite Filler
Graphite is widely used because of its excellent sealing performance and ability to handle elevated temperatures. It is commonly selected for refinery, petrochemical, and power applications.
2. PTFE Filler
PTFE provides excellent chemical resistance and is often used when handling aggressive chemicals or corrosive media.
3. Vermiculite and Phlogopite
These fillers are frequently considered for higher-temperature services where conventional fillers may not be sufficient.
4. Ceramic Filler
Ceramic fillers are used for extremely high-temperature applications where specialized thermal resistance is required.
The ideal filler depends on process media, operating temperature, pressure requirements, and chemical compatibility.
Inner Ring and Outer Ring Considerations
Modern stainless steel spiral wound gaskets often incorporate inner and outer rings to improve performance and installation reliability.
Inner Ring
The inner ring helps:
- Reduce turbulence
- Protect winding elements
- Improve compression control
- Increase blowout resistance
IGP notes that inner rings are normally manufactured using the same metal as the winding strip.
Outer Ring
The outer ring functions as a centering device that simplifies installation and helps prevent gasket misalignment. Carbon steel, SS304, and SS316 are commonly used outer-ring materials.
ASME B16.20 Compliance
Spiral wound gaskets used in industrial piping systems are commonly manufactured in accordance with ASME B16.20, which establishes construction, marking, material identification, and dimensional requirements for metallic gaskets.
Get expert guidance on spiral wound gasket configurations from IGP Engineers.
How to Select the Right Spiral Wound Gasket Material
At IGP Engineers, gasket selection is approached based on the actual operating conditions rather than treating one stainless-steel grade as a universal solution. Engineers and procurement teams should evaluate:
- Operating temperature and thermal cycling
- Process media and chemical compatibility
- Corrosion and oxidation exposure
- Operating pressure and flange class
- Flange dimensions and configuration
- Inner and outer ring requirements
- Applicable standards, including ASME B16.20
- Maintenance and expected service conditions
By considering the complete gasket configuration, IGP Engineers supports application-specific selection of a high temperature gasket or corrosion resistant gasket. Our spiral wound gaskets are available to standards including ASME B16.20, ASME B16.5, ASME B16.47, API 601, DIN, JIS, AWWA and BS, helping match dimensions and configurations to the specified flange system.
Engineers should evaluate the SS winding grade, filler, ring configuration, flange standard, pressure class, temperature and process media for reliable service.
Conclusion
Choosing among SS304, SS316, SS321, and SS347 requires understanding the relationship between corrosion resistance, temperature capability, and process conditions.
By evaluating both the winding metal and filler material, engineers can select stainless steel spiral wound gaskets that deliver long-term sealing performance, operational safety, and maintenance efficiency.
Looking for the right stainless steel spiral wound gaskets for your application? Contact IGP Engineers to discuss custom sealing solutions tailored to your operating conditions.
