Spiral Wound Gasket with outer ring
Spiral Wound Gaskets (SWG) is wound alternatively by V or W shaped metal hoop and non-metal filler of various kinds of materials selected based on specific working condition,with inner ring and/or out ring as options.The inner ring and outer ring are used to enhance the compressive capacity of the gasket. Meanwhile, they cooperate with the assembly of different flange surfaces to improve the performance of the spiral wound gasket.
It is made of metallic winding and a soft filler material, combining the strength of metal with the sealing properties of a soft filler.
The inner ring of the metallic spiral wound gasket usually selects the corresponding stainless-steel material according to the different pipeline media, and the material selection of the inner ring is usually consistent with that of the steel strip. In the ASME standard, it is required that all spiral wound gaskets filled with PTFE should be equipped with an inner reinforcing ring.
The outer ring of the spiral wound gasket can usually select stainless-steel material, or adopt carbon steel material with anti-corrosion treatment by galvanizing and plastic coating processes.
ASME B16.20 Spiral Wound Gaskets
ASME B16.20 is the most popular standard for Spiral Wound Gaskets
ASME B16.20 covers metal ring-joint gaskets, spiral-wound metal gaskets, and grooved metal gaskets with covering layers and offers comprehensive solutions
Spiral Wound Gasket with outer ring struction as below
Outer Ring
The outer ring (sometimes known as centering ring or guide ring) can be manufactured from almost any available solid metal material. The outer ring serves to centre the gasket on the flange, act as an anti blow-out device and a compression stop to prevent the filler and windings from being crushed too much.
Material grade :Carbon Steel, with or without zinc coating,SS304, SS304L, SS316, SS316L,321,S31803,S32750,Inconel 625 etc
Sealing Element（Filler +Winding material）
The sealing element consists of a metallic winding and a soft non-metallic filler material. This part of the gaskets is where the primary sealing occurs. The sealing element can be produced from a range of different materials (listed below) to suit your individual application.
How to choose the gasket material?
To choose the right gasket material ,you should consider different factors, including temperature, pressure, chemical compatibility, and Flange type. So to understand the property and Character of the different gasket material (Ring and filler material)is very important.
You would find the character details of the gasket material as below
| Ring & Strip Materials | ||||||
| Minimum | Maximum | GuideRing Color Code | ||||
| Material | F | C | F | C | Abberviation | |
| SS 304 | -320 | -195 | 1400 | 760 | 304 | Yellow |
| SS 316L | -150 | -100 | 1400 | 760 | 316L | Green |
| SS 347L | -150 | -100 | 1400 | 760 | 317L | Maroon |
| SS 321 | -320 | -195 | 1400 | 760 | 321 | Turquoise |
| SS347 | -320 | -195 | 1700 | 925 | 347 | Blue |
| Carbon Steel | -40 | -40 | 1000 | 540 | CRS | Silver |
| Alloy 20 | -300 | -185 | 1400 | 760 | A-20 | Black |
| Hastelloy B3 | -300 | -185 | 2000 | 1090 | HASTB | Brown |
| Hastelloy C276 | -300 | -185 | 2000 | 1090 | HASTC | Belge |
| Incoloy 800 | -150 | -100 | 1600 | 870 | IN 800 | White |
| Incoloy 825 | -150 | -100 | 1600 | 870 | IN 825 | White |
| Inconel 600 | -150 | -100 | 2000 | 1090 | INC 600 | Gold |
| Inconel 625 | -150 | -100 | 2000 | 1090 | INCO 625 | Gold |
| Inconel X750 | -150 | -100 | 2000 | 1090 | INX | No Color |
| Monel 400 | -200 | -130 | 1500 | 820 | MON | Orange |
| Nickel 200 | -320 | -195 | 1400 | 760 | NI | Red |
| Titanium | -320 | -195 | 2000 | 1090 | TI | Puple |
Filler Material
The filler material is the key parts for the winding in the sprial wound gasket,it provides flexibility and ensures a tight seal.
| Material | Max Temperature (°C) | Application |
|---|---|---|
| Graphite | 550 – 850°C | High-temperature, steam, and oil & gas |
| PTFE (Teflon) | 260°C | Chemical and corrosive applications |
| Mica | 1000°C | High-temperature exhaust & combustion systems |
Standards & Specifications
Spiral wound gaskets are produced according to industry standards:
- ASME B16.20 – Standard for gaskets for pipe flanges.
- API 6A – Used in high-pressure oilfield applications.
- BS 3381 – British Standard for metallic gaskets.
- EN 1514-2 – European standard for gasket dimensions
Pressure Ratings (Class)
Spiral wound gaskets are available for various pressure classes according to ASME B16.5 and API 6A:
- ASME Classes: 150, 300, 600, 900, 1500, 2500
- API 6A Classes: 5000, 10000, 15000 psi
Typical Description of a GI Type Spiral Wound Gasket
Product Name: Spiral Wound Gasket
Size: 6 Inch, DN 300
Standard: ASME B16.20
Class 300 LB
Material of Outer Ring: SS316L
Filler: SS316L Hoop Filled with Flexible Graphite
Want to learn more of the other type of Spiral Wound Gasket?
Basic type Spiral Wound Gasket (Style R Gasket)
Style RIR – (Style RIR – Flexible Graphite Filler with inner metal ring)
Style CGI Gasket (Spiral wound gasket with outer ring and inner ring)
