ASTM A182 F55 UNS S32760 Bleed Rings Super Duplex Stainless Steel

ASTM A182 F55 Bleed Rings

ASTM A182 F55 Vent Ring. ASTM A182 covers wrought stainless steel and alloy materials for high temperature service, including flanges, fittings, and valves.

Grade F55 (UNS S32760): A super duplex stainless steel with high chromium (25%), molybdenum (3.5-4.5%), and nitrogen (0.2-0.3%) content for excellent strength and corrosion resistance. Meets NACE MR0175/ISO 15156 standards for sour services.

Vent Ring Function:

Purpose: Installs between flanges to provide a port for venting, draining, or pressure testing in piping systems. Venting is essential during hydrostatic testing or draining of fluids.

Design: Typically includes a threaded hole for a valve or plug connection, matching flange dimensions (ASME B16.5/B16.47) for seamless integration.

Vent rings are often used in place of orifice flanges.

They are easier to install and more affordable than orifice flanges in environments involving hazardous materials or contamination

Convenient for accessing drain lines, sampling, or connecting instruments

They can also reduce or eliminate pressure prior to flange removal by using a valve or blind flange.

This procedure is common when replacing a leaking valve in a piping system.

Applications include offshore oil/gas, chemical processing, desalination, and seawater systems where chloride-induced corrosion (pitting, crevice) is present.

Due to its duplex structure (austenite + ferrite phases), F55 is suitable for high pressure, high temperature, and corrosive services.