Spiral Wound Gaskets: Decoding The Colors

Updated Jan 2024

Decoding The Colors 

Spiral 2Spiral wound gaskets  are a specific design of gaskets used in high-temperature and high-pressure applications, such as in the oil and gas industry or chemical processing plants. These gaskets are made by winding a metal strip and a filler material (usually graphite or PTFE) in a spiral pattern. The outer and inner diameters of the gasket may have additional layers of metal and filler material. This design provides a combination of strength, resilience, and the ability to withstand extreme conditions.

And - the colors of the spiral wound gasket do matter! The industry standards require the gaskets are to be color-coded. This helps identify what the gasket is made of quickly and easily.

With spiral wound gaskets, there are two distinct colors, the color of the outside rim and the color stripe along the rim. Using our color guide below, you can see the different materials available. Those of you in the oil and gas industry have likely seen these gaskets before. The outside rim is usually yellow (304 SS), green (316 SS), or orange (monel). All these materials are great for this type of industry as it seals at high temperatures and pressures. The rim stripe is usually gray (Graphite) and is used in many different industries and applications.

Outside Rim

Titanium

Titanium has excellent corrosion properties in elevated temperatures, oxidant service, Nitric acid, and caustic solutions. This material can withstand 2012ºF (1100ºC), with a hardness of 90 HRB. The outside rim color is purple.

Nickel

Nickel has excellent resistance to caustic solutions. This material can withstand temperatures up to 1112ºF (600ºC). The outside rim color is red.

Monel

Monel has excellent resistance to the majority of acids and alkalis, except heavily oxidant acids. This material can withstand temperatures up to 1500ºF (815ºC), with a hardness of 70 HRB. Monel is made up of 67% Nickel and 30% Copper. The outside rim color is orange.

Inconel

Inconel can withstand temperatures up to 1,832ºF (1,000º). This material has great resistance against corrosion. Can withstand pressure up to 5800psi while under intense heat. The outside rim color is gold.

Hastelloy B

Hastelloy B can withstand temperatures up to 1,832ºF (1,000ºC). This material has excellent resistance to pitting, corrosion, stress cracking, and thermal stability. However, will corrode in oxidizing environments. The outside rim color is brown.

Hastelloy C

Hastelloy C can withstand temperatures up to 1,832ºF (1,000ºC). Widely regarded as one of the most corrosion-resistant alloys available. Good for chemical and petrochemical processing, pulp and paper, and waste equipment. The outside rim color is tan.

Carbon Steel

Carbon Steel can withstand temperatures up to 932ºF (500ºC). This material is mostly used in manufacturing jacketed gaskets and ring joints. Carbon steel has low corrosion resistance, this material should never be used in water, diluted acids, or saline solutions. The outside rim color is silver.

Alloy 20

Alloy 20 can withstand temperatures up to 1400ºF (760ºC). This material was specifically developed for applications requiring resistance to sulfuric acid. Ally 20 has a hardness level of 150 HRB. The outside rim color is black.

304 Stainless Steel

304 Stainless Steel can withstand temperatures up to 1004ºF (540ºC). This material has a hardness of 68 HRBand is mostly used in manufacturing industrial gaskets because of its excellent resistance to corrosion, low cost, and availability. It is rated for a MAX temp of 1004ºF (540ºC) but continuous service temp is limited to 788ºF (420ºC). This alloy is 18% Chromium (Cr) and 8% Nickel (Ni). The outside rim color is yellow.

316 Stainless Steel

316 Stainless Steel is rated for temperatures up to 1472ºF (800ºC). This material has a hardness of 68 HRB and has excellent corrosion resistance. This alloy is 18% Nickel (Ni), 13% Chromium (Cr), and 2% Molybdenum (Mo). 316 Stainless Steel is rated for a Max temp of 800ºC but a continuous service temp of 760ºC. The outside rim color is light green.

321 Stainless Steel

321 Stainless Steel is rated for temperatures up to 1598ºF (870ºC). This material has a hardness of 68 HRB and the chemical makeup reduces inter-granular precipitation and corrosion. This alloy is made up of 18% Chromium (Cr) and 10% Nickel (Ni) stabilized with Titanium (Ti). The outside rim color is dark green.

347 Stainless Steel

347 Stainless Steel is rated for temperatures up to 1598ºF (870ºC). This material has a hardness of 68 HRB and the chemical makeup reduces carbonate precipitation and inter-granular corrosion. This alloy is 18% Chromium (Cr) and 8% Nickel (Ni) stabilized by Calcium (Ca) and Tantalum (Ta). The outside rim color is light blue.

 
 
 
 
 
 
 
 
 
 

Stripe Color

Mica

Mica is rated to withstand temperatures up to 1832ºF (1000ºC). This material is manufactured from mica sheets with an inorganic binder. This filler is resistant to most chemicals such as solvents, acids, caustics, hydrocarbons, and organic products. Generally, Mica does not exhibit terrific sealability and is usually banded with flexible graphite. Together, these materials work to deliver flexibility and high-temperature resistance. The stripe color is pink.

Ceramic

Ceramic is rated for temperatures up to 1994ºF (1090ºC). This filler is used in high-temperature situations. The stripe color is lime green.

PTFE (Polytetrafluoroethylene)

PTFE is rated for temperatures put o 500ºF (260ºC). This filler should be confined in a grooved flange or with an inner ring to improve durability and avoid buckling. The stripe color is white.

Flex Graphite

Flex Graphite is rated for temperatures up to 842ºF (450ºC). This filler is used mainly in refineries, chemical, petrochemical, and pulp and paper industries. Flex graphite is known to have “fire-safe” properties and is used with flammable products such as fuels and hydrocarbons. The stripe color is gray.

 

 

 

APG Wants To Be Your Gasket Supplier

Gaskets come in many shapes, sizes, and materials and you may not be sure where to start when shopping for the products you need! APG can help! Since 1943 we have been providing our clients with the high-quality products they need, as well as assistance in choosing the specific product and material that will work best for their application. Shop our gasket selection now, and if you have questions please don’t hesitate to contact us or look into our knowledge base to help find the right answer.

We look forward to exceeding your expectations in both quality and service!

 

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