Weld Neck Flanges

Weld neck flanges are mounting components for pipes designed to be butt-welded to the pipe end. They feature a tapered hub (neck) that transfers stresses from the pipe to the flange, reducing stress concentration at the base of the weld. As a result, they are frequently used wherever high mechanical strength and connection tightness are required.

Weld neck flanges are widely used in various piping systems. They are most commonly found in locations requiring durable, leak-proof connections and resistance to high pressure or temperature.

• Petrochemical and refining industry
• Chemical and pharmaceutical industry
• Shipbuilding and offshore (marine applications)
• Power engineering and boiler systems
• Food industry and brewing (where corrosion resistance is required)
• Automotive and heavy industry
• Water and sewage systems and water treatment
• Small workshops and home garage solutions where a durable and tight pipe correlation is needed

In our store, we offer flanges made exclusively of stainless steel, acid-resistant steel, and heat-resistant steel – we do not sell aluminum or carbon steel components. The most commonly used grades are:

• Austenitic stainless steel– examples: AISI 304 (EN 1.4301). Good corrosion resistance under standard conditions.
• Acid-resistant steel– examples: AISI 316 / 316L (EN 1.4401 / 1.4404). Better resistance to aggressive chemical environments, often used in the chemical and marine industries.
• Heat-resistant steel– examples: AISI 310 / 310S. Designed for applications at elevated temperatures.
• Ferritic steels– e.g., grades from the 430 group, used where magnetic properties and moderate corrosion resistance are required.

In the text, we use both colloquial terms (stainless steel, heat-resistant steel, ferritic steel) and professional AISI/EN designations to facilitate material identification.

Weld neck flanges come in forged and rolled versions; forged flanges are preferred where maximum strength is required. Typical sealing surfaces include raised face (RF) and Ring Type Joint (RTJ), used depending on tightness and standard requirements.

Dimensions and pressure classes of flanges often comply with the following standards:

• EN 1092-1 (PN standards for Europe)
• ASME B16.5 / ANSI (American standards)

This makes selecting a flange for an existing system simpler – just specify the diameter, pressure class (e.g., PN or ASME class), and sealing type.

• Mechanical strength: the neck distributes stress and minimizes the risk of cracks during welding.
• Corrosion resistance: acid-resistant steel (e.g., 316/316L) ensures a longer service life in aggressive environments.
• Versatility: suitable for high temperatures, high pressure, and aggressive media.
• Serviceability: flanged connections facilitate the disassembly of pipeline sections for maintenance.

The offer is addressed to installation companies, industrial plants, shipyards, maintenance departments, as well as DIY enthusiasts and workshops. If you are designing or repairing piping systems that require durable and leak-proof connections, weld neck flanges will often be the best choice.

How to choose the right weld neck flange?

When selecting, pay attention to:

• Material (corrosion and temperature resistance) – stainless steel 304 vs 316/316L vs heat-resistant steel.
• Dimensional standard (EN/PN or ASME/ANSI) and pressure class.
• Sealing surface type (RF, RTJ, etc.).
• Whether the flange should be forged – required for elevated loads.

If you need help with selection – contact our team, provide the pipe diameter, pressure class, and type of medium, and we will advise you on the best solution.

Weld neck flanges are reliable components for joining pipes in systems where durability, tightness, and resistance to mechanical and chemical loads are required. Our offer includes stainless, acid-resistant, and heat-resistant steel flanges, manufactured in accordance with industrial standards (EN / ASME) and available in forged versions. This makes it easy to match them to industrial, marine, food, or workshop installations.