Spiral Wound Gaskets: Types, Materials & How to Select the Right One
Spiral wound gaskets are the workhorse sealing element on flanged connections across refineries, chemical plants, and pipelines. A V-shaped metal winding alternated with a soft filler gives them the resilience to handle pressure cycling, thermal expansion, and flange rotation that would crush a flat sheet gasket. Choosing the wrong winding metal or filler, though, is one of the most common causes of flange leaks in hydrocarbon service.
How a Spiral Wound Gasket Is Built
Three elements do the work. The winding — typically 304 SS, 316L SS, Monel, or Inconel strip — provides mechanical strength and recovery. The filler — flexible graphite or PTFE — does the actual sealing. The outer guide ring (usually carbon steel) centers the gasket on the bolt circle and acts as a compression stop, while an optional inner ring prevents inward buckling and shields the winding from turbulent media. ASME B16.20 requires inner rings for PTFE-filled gaskets and for larger sizes in Class 900 and above.
Winding & Filler Selection
| Service | Winding | Filler |
|---|---|---|
| General hydrocarbon, steam | 304 / 316L SS | Flexible graphite |
| Strong acids, chlorine, oxidizers | 316L SS, Hastelloy | PTFE |
| Seawater, hydrofluoric acid | Monel 400 | PTFE |
| High temp above 850°F | Inconel 600 | Graphite (inhibited) |
Reading the Color Code
ASME B16.20 assigns a solid color on the outer ring edge for the winding metal (yellow = 304, green = 316L, orange = Monel, gold = Inconel 600) and a stripe for the filler (gray = graphite, white = PTFE). If the paint is gone, don't guess — verify against the piping spec before it goes in a hydrocarbon flange.
Common Failure Causes
Most spiral wound failures trace back to installation, not the gasket: under-torqued bolts that never seat the winding, over-compression without an inner ring, reusing a gasket after breakout, or mixing a Class 150 gasket into a Class 300 joint. Always torque in a star pattern to the gasket manufacturer's target stress, in at least three passes.
Get the Right Gasket for Your Flange Spec
We stock spiral wound gaskets in standard ASME B16.20 sizes and cut custom gaskets to your drawing, with material certs available on request. Send the flange size, pressure class, media, and temperature through the quote form at the top of this page — or call (979) 233-6223 — and our team will respond with pricing and lead time in 1–2 business hours.