Threaded forged fittings are primarily used to connect small-bore piping (NPS 4 and smaller) in non-critical, low-to-medium pressure applications where welding is hazardous or impractical.

Common applications include instrument air lines, cooling water systems, fire protection piping, and maintenance joints. Unlike cast fittings, they are manufactured through high-pressure forging, which aligns the grain structure of the steel. This provides the structural integrity necessary for industrial environments, ensuring they can withstand vibration and thermal cycling better than cast alternatives.

According to ASME B16.11 standards, threaded fittings are typically available in three pressure classes: Class 2000, Class 3000, and Class 6000.

These classes do not represent a fixed pressure limit (like 3000 psi) but rather correlate to the wall thickness of the connecting pipe to ensure the fitting is not the weak point in the system:

• Class 2000: Correlates to Schedule 80 (XS) pipe.

• Class 3000: Correlates to Schedule 160 pipe (Standard for high-pressure hydraulics).

• Class 6000: Correlates to Schedule XXS (Double Extra Strong) pipe.

The critical difference lies in the thread angle and profile, making NPT and BSPT threads fundamentally incompatible.

• NPT (National Pipe Taper): The American standard (ANSI/ASME B1.20.1) with a 60° flank angle and flattened crests/roots.

• BSPT (British Standard Pipe Taper): The European/Asian standard (ISO 7) with a 55° flank angle and rounded crests/roots.

Engineering Warning: Attempting to mate an NPT fitting with a BSPT port will result in a spiral leak path due to the mismatched angles. Forcing the connection will damage the threads and compromise the pressure seal.

Yes, we supply both grades, though we recommend 316L for any application involving chlorides or marine environments.

While 304 Stainless Steel is suitable for general indoor plumbing and freshwater applications, it is susceptible to crevice corrosion in the root of the threads if exposed to salt. 316/316L Stainless Steel contains 2-3% Molybdenum, which stabilizes the passive oxide film and provides superior resistance to pitting and crevice corrosion in harsh chemical or offshore environments.

We provide full traceability for our products via EN 10204 Type 3.1 Mill Test Certificates (MTC).

For high-integrity piping, a simple certificate of compliance is insufficient. Our Type 3.1 MTCs are issued by an independent inspection authority and include:

1. Chemical Analysis & Mechanical Properties: Actual test results (tensile strength, hardness, impact test) for the specific batch supplied.

2. Heat Number Traceability: The certificate is linked directly to the heat code stamped on the fitting, allowing you to trace the material back to the original steel ladle analysis.