Markings on spiral wound gaskets can be vital for manufacturers who use them. Informing you of the size of the gasket and the load the gasket can handle, markings can also show you the pressure classes and suitability to applications.
These markings are essential in helping to make the right decision on gasket choice, as well as providing you with a high level of quality assurance – a prerequisite for high-specification applications.
With the ability to withstand fluctuating temperatures and pressures, a spiral wound gasket is designed to prevent leaks and avoid contamination, with three key elements forming a robust spiral wound gasket:
1 – The outer ring is used to centre the gasket when inserted into the application.
2 – The inner ring – prevents windings from breaking.
3 – The sealing element – the part that creates the actual seal to prevent leaks, incorporating windings and filler materials.
Spiral wound gasket manufacturing process
A versatile product offering incredible sealing properties, spiral wound gaskets are capable of providing a sealing solution in configurations that face extreme temperature and pressure situations.
Spiral wound gaskets are used in multiple applications across a range of industry sectors to prevent leaks and support joints.
Distinguished by various marks that provide further detail about the gasket itself, spiral wound gaskets are manufactured from thin metal strips and combined with non-metallic filler.
They include a locator outer ring within the bolt circle that is used to support the sealing element of the gasket and an inner ring that provides a heat and corrosion resistance barrier that protects the spiral aspect of the seal.
The most commonly manufactured spiral wound gasket is a 316 stainless steel inner ring with a carbon steel outer, combined with graphite filler material.
However, gaskets come in various materials, shapes, and sizes, making them extremely flexible and versatile.
During manufacturing, these gaskets will be marked with the manufacturer’s logo, the manufacturing standard reference, size and pressure class, filler material, winding material, and inner and outer material.
Spiral wound gasket marks
Spiral wound gaskets have several different markings, and it is good to be aware of these as each one provides you with essential information about the gasket itself.
These markings include:
Design Standard, ASME B16.20 – this is the industry standard to which all gaskets should be manufactured. Allowing for easy identification, the design standard shows the gasket’s adherence to set standards and guidelines.
Manufacturers’ information, including name – putting their stamp on the gaskets produced, the manufacturer’s name will typically be located on the right-hand side of the gasket.
Winding and filler material – this information lets you know what the gasket comprises and if it will be suitable for your specific application.
Pressure classification – these markings of spiral wound gaskets will tell you the overall load the gasket can handle. Pressure classes typically come in 7 pressure ratings: 150, 300, 400, 600, 900, 1,500, and 2,500.
Diameter – these markings of spiral wound gaskets will tell you the gasket size, which generally ranges from 3.2mm to 4.5mm, with larger diameters found ranging from 5.5mm to 7mm.
Spiral wound gasket colours – outside rim colours provide you with information about the gasket winding materials, whereas the rim stripe colour indicates the gasket filler material.
For example, the colours for winding materials include:
- Yellow – 304 stainless steel
- Green – 316 stainless steel
- Turquoise – 321 stainless steel
- Blue – 347 stainless steel
- Orange – manufactured from Manel
- Black – Alloy 20
- Silver – carbon steel
- Brown – Hastelloy B
- Beige – Hastelloy C
- Gold – Inconel
- Red – Nickel
- Purple – Titanium
Filler material colours include:
- Pink – Mica paper
- Gray – graphite
- White – PTFE
- Light green – ceramic
Knowing the basics surrounding spiral wound gasket markings helps you to avoid selecting the wrong gasket for your application, saving you considerable time and money in the long term.
Benefits of using a spiral wound gasket
- Suitable in fluctuating temperature ranges
- Apt for high-pressure applications
- Typically found in valves, pipelines, and pumps
Specialist Sealing Products
At SSP, we design and manufacture the highest quality, professional spiral wound gaskets.
Providing you with state-of-the-art manufacturing, you can rely on our team to provide you with high-quality, perfectly suited gaskets for your specific applications.
We follow set industry standards and provide product and material certifications, including batch numbers, cure dates, and shelf life, with full traceability.
With high-quality controls in place, we ensure integrity and customer satisfaction across all of our products.
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