ASME B16.20 Spiral Wound Gasket 316L Outer Ring 316L Inner Ring Flexible Graphite Filler CGI Type

Overview

Spiral wound gasket manufactured to ASME B16.20 with a 316L centering ring, a 316L inner ring and flexible graphite filler. Built for steam, chloride-bearing and thermally cycled service where mixed-material gaskets typically fail at the outer ring first.

Construction

Three components: a 316L centering ring that locates the gasket on the flange face and limits compression; a spiral-wound sealing element of pre-formed 316L strip and flexible graphite filler; and a 316L inner ring that prevents inward buckling of the winding and shields the sealing element from process-fluid erosion.

Why 316L for Both Rings

316L is the low-carbon grade of 316 (C ≤ 0.03%). It resists sensitization and the intergranular corrosion that standard 316 can develop after welding or heat exposure, and its molybdenum content gives pitting and crevice corrosion resistance in chloride and marine environments. With both rings in 316L, no carbon-steel component remains to corrode.

Filler Performance

Flexible graphite is chemically inert and non-aging. Service range −200 °C to +450 °C in oxidizing media, up to 650 °C in steam. High recovery under pressure and temperature cycling, low creep relaxation, and it conforms to minor flange surface irregularities.

Sizes and Ratings

Typical Service

Heat exchanger channels and floating heads, pipe flanges, valve bonnets and pump casings in refineries, petrochemical plants, chemical processing, power generation, LNG and offshore installations.

Ordering

Specify flange size, pressure class and flange facing, or send a drawing for non-standard dimensions. Material certificates (EN 10204 3.1) and dimensional inspection reports are supplied with each batch.