Type SG spiral wound gaskets (also known as style CG) supplied by AMG Sealing are highly resilient semi-metallic sealing solutions designed for use in standard industrial piping systems. Featuring a V-shaped metallic winding strip interleaved with soft filler material, Type SG gaskets incorporate a solid metal outer guide ring and no inner ring. This configuration provides optimum sealing performance, ease of alignment, and mechanical resistance under variable pressure and temperature conditions.
By combining different winding materials and metals, these spiral wound gaskets can be custom-tailored to suit a wide variety of process environments, capable of sealing fluid pressures up to 400 bar and operating across temperatures from cryogenic levels up to 1000°C.
Applications
Type SG gaskets are the industry standard for raised-face (RF) flange configurations in low-to-medium pressure classes where an inner ring is not required. They are broadly deployed across process pipelines, heat exchangers, and pressure vessels within oil refineries, chemical processing units, water treatment infrastructure, and commercial steam utilities.
Gasket Construction & Component Functions
- Outer Guide/Centring Ring: Accurately aligns and centres the gasket elements inside the flange bolt circle, acts as an integral compression stop to prevent over-tightening under bolt load, and assists in blowout prevention.
- V-Shaped Sealing Element: Engineered from alternating layers of preformed metallic ribbon and soft filler material (such as flexible graphite, PTFE, or mica), providing spring-like recovery to maintain a tight seal under thermal expansion and vibration.
- Unrestricted Bore: Ideal for specific pipeline configurations where maximum flow and fluid dynamics are required without inner ring obstruction, provided the filler material behaves predictably under full torque loads.
Availability and Options
AMG Sealing stocks and supplies SG spiral wound gaskets across an extensive range of nominal sizes and pressure ratings conforming strictly to ASME B16.20, EN 1514-2, and EN 12560-2 dimensions. Standard materials feature a treated carbon-steel outer ring, 316L stainless-steel windings, and flexible graphite filler. Exotic materials, including Monel, Titanium, and Inconel windings, can be provided on demand.
Note: In accordance with the latest ASME B16.20 revisions, inner rings (Type SGIR) are highly recommended or mandated for certain high-pressure classes and specific filler materials (such as PTFE) to eliminate risk of inward buckling.
For sizes and material options, please see the technical data sheet below.