Threaded Flange Manufacturer | NPT Threaded Pipe Flanges

What Is a Threaded Flange?

 

A threaded flange (also called screw flange) is a type of pipe flange that connects to a pipe without welding. The flange bore is machined with internal threads that match the external threads of the pipe.

This design allows easy installation and removal without welding, making threaded flanges suitable for specific applications where welding is not allowed or not recommended.

In some cases, a seal weld may be applied to enhance leak prevention.

Threaded flanges are commonly used in small diameter, high-pressure piping systems.

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Threaded Flange Applications

Threaded flanges are widely used in:

• Oil & gas systems

• Steam pipelines

• Water supply systems

• Galvanized pipe installations

• Hazardous environments where welding is restricted

They are generally recommended for pipelines:

• Below 4 inches (NPS 1/2” – 4”)

• With sufficient wall thickness for threading

• Operating under moderate pressure

They are not recommended for:

• Thin wall pipes

• Systems with frequent temperature cycling

• Temperatures above 260°C or below -45°C

According to ASME B31.3:
Steel pipes used for steam service above 250 psi or water service above 100 psi at temperatures above 220°F shall be seamless and minimum Schedule 80 thickness.

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Our Threaded Flange Supply Range

Standards

• ASME B16.5

• ASME B16.47

• GOST (for Russia & CIS markets)

Material Grades

• ASTM A105 (Carbon Steel)

• ASTM A182 F5, F9, F11, F22, F91 (Alloy Steel)

• ASTM A182 F304, F304L, F316, F316L (Stainless Steel)

Size Range

• 1/2” to 24”

Pressure Ratings

• Class 150 to Class 2500

Facing Types

• Raised Face (RF)

• Ring Type Joint (RTJ)

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Types of Threaded Flanges

There are two primary threaded flange sealing structures:

Standard Sealing Type

Sealed through mating flange faces using a gasket (RF or RTJ). This is the most common threaded flange type.

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Facing Types

Raised Face (RF) Threaded Flange

Raised Face threaded flanges have a small raised portion around the bore where the gasket is seated.

Raised face height:

• Class 150 & 300 → 1.6 mm (1/16”)

• Class 400–2500 → 6.4 mm (1/4”)

RF flanges are compatible with:

• Soft gaskets

• Semi-metallic gaskets

• Metallic gaskets

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RTJ (Ring Type Joint) Threaded Flange

RTJ threaded flanges feature a precision-machined groove to accommodate a metal ring gasket.

RTJ flanges are recommended for:

• High-pressure services

• High-temperature environments

• Critical oil & gas pipelines

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Installation Advantages

Compared with weld neck or slip-on flanges, threaded flanges offer:

• No welding required

• Easier installation

• Faster maintenance

• Reduced fire risk during installation

This makes threaded flanges ideal for hazardous or confined working environments.

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Measurement & Dimensional Data

For accurate threaded flange production, the following dimensions are required:

• O – Outside diameter

• C – Flange thickness

• R – Raised face diameter

• X – Hub diameter at base

• Y – Length through hub

• T – Minimum thread length

• Q – Bolt circle diameter

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Why Choose Our Threaded Flanges?

• Strict dimensional inspection

• High-precision thread machining

• Pressure-tested products

• Export experience to Russia & Central Asia

• Competitive pricing and stable supply

 

In addition to threaded flanges, we also supply a full range of industrial pipe flanges for different piping systems and pressure requirements, including:

• Weld Neck Flanges

• Slip On Flanges

• Blind Flanges

• Socket Weld Flanges

• Lap Joint Flanges

• Threaed Flanges

These flanges are manufactured according to ASME B16.5, EN,1092-1 and GOST standards and are widely used in oil and gas, petrochemical, and industrial pipeline applications.