ASTM A815 WPS31803-S Duplex Steel Cap ASME B16.9 Buttweld Duplex 2205 Pipe Fittings


Mechanically, it seals the bore of the pipe to contain internal pressure (rated up to Class 1500/2500 depending on the schedule) and prevents internal corrosion of the pipe ID by blocking fluid ingress. Unlike a blind flange (which is bolted), this cap is permanently fused to the pipe wall, providing a 100% leak-proof seal that eliminates flange gasket maintenance. It is designed to match the pipe's Schedule (e.g., Sch 40, Sch 80, Sch 160), ensuring the inside diameter (ID) and outside diameter (OD) match perfectly for smooth flow transition and complete weld penetration.


Equivalent Grades of ASTM A815 WPS31803 Duplex Stainless Steel Pipe Cap

Chemical Compositions of ASTM A815 WPS31803 Duplex Stainless Steel Pipe Cap Duplex 2205 Pipe Fittings End Cap

Mechanical Properties of ASTM A815 WPS31803 Duplex Stainless Steel Pipe Cap Duplex 2205 Pipe Fittings End Cap

This fitting is used during specific stages of a piping system's lifecycle:

• End-of-Line Termination (Permanent): Used at the very end of a pipeline run to permanently dead-end the flow, ensuring the system holds pressure.

• Hydrostatic/Pneumatic Pressure Testing: Used temporarily during the pre-commissioning phase. Caps are welded onto test headers to seal the system so it can be filled with water or air to check for leaks.

• System Maintenance & Shutdowns (Isolation): Used during turnarounds (shutdowns) to cap off decommissioned branch lines or to isolate a section of pipe that needs repair while the rest of the plant stays online.

• Future Expansion Planning: Used to cap a "stub-out" during initial construction. The cap is welded in place now but cut out later when new equipment is added to the system.

Applications

• Offshore Oil & Gas (Subsea & Topsides): Used in seawater injection lines, crude oil export risers, and firewater systems where chloride pitting and Stress Corrosion Cracking (SCC) are major risks.

• Chemical Processing Plants: Used in handling acetic acid, formic acid, and caustic chlorides where the dual-phase microstructure resists intergranular attack.

• Pulp & Paper Mills: Used in digesters and bleach plants (containing chlorine dioxide).

• Flue Gas Desulfurization (FGD) Systems: In coal-fired power plants, used to cap ductwork handling acidic condensates.

• Marine/Shipbuilding: Ballast water treatment systems and deck piping on vessels.

• Heat Exchanger Headers: Sealing the end of tube bundles in high-chloride cooling water circuits.