Stainless steel weld neck flanges 1.4404 / 316L

What are weld neck flanges?

Weld neck flanges are pipe flanges with a long, tapered hub that is butt‑welded to the pipe. The tapered neck transfers stress smoothly from the flange to the pipe, making this type of flange especially suitable for high‑pressure and high‑temperature systems. They are commonly used where a strong, leak‑resistant connection and good alignment are required.

Material: 1.4404 / 316L — what it means

The flanges in this category are made from stainless steel 1.4404, commonly known as AISI/ASTM 316L. The European/DIN designation is 1.4404 (X2CrNiMo17-12-2); the US designation is 316L. This is an austenitic, low‑carbon stainless steel containing chromium, nickel and molybdenum. The low carbon content (the “L” in 316L) improves resistance to intergranular corrosion after welding, which is important for welded flanges.

Key properties and benefits

• Corrosion resistant: Good resistance to many corrosive media, including chloride environments and mild chemical attack — ideal for marine, chemical and offshore use.
• Weldability: 316L welds readily; the low carbon grade reduces the risk of sensitisation and intergranular corrosion in welded joints.
• Durable and tough: Good mechanical properties and toughness across a wide temperature range, including low temperatures.
• Hygienic and easy to clean: Suitable for food, pharmaceutical and medical applications where cleanliness is essential.
• Reliable stress distribution: The weld neck design reduces stress concentrations at the flange‑to‑pipe junction, improving lifecycle under cyclic loads.

Typical industries and applications

Stainless steel 1.4404 / 316L weld neck flanges are used across a broad range of sectors. Examples include:

• Oil & gas and petrochemical pipelines and process equipment
• Offshore and marine systems (sea water, salt atmosphere)
• Chemical and fertiliser plants
• Food processing, beverage and pharmaceutical manufacturing
• Power generation, heat exchangers and boilers
• Shipbuilding and port infrastructure
• Automotive and aerospace components
• Small workshops and garage fabrications where a high‑quality, corrosion‑resistant flange is required

Who should choose these flanges?

This product is suitable for plant engineers, pipe fabricators, maintenance teams, OEMs and contractors who need a robust, weldable flange with high corrosion resistance. They are ideal when longevity, leak tightness and structural integrity are priorities — from DIY fabrications to heavy industrial installations.

Standards, faces and common specifications

Weld neck flanges in 1.4404 / 316L are typically manufactured to recognised flange standards such as EN (DIN) standards and ASME/ANSI specifications. Common flange face types include:

• Raised Face (RF)
• Flat Face (FF)
• Ring Type Joint (RTJ)

If you require specific pressure/size classes or certificates (material certificates, mill test reports), these can be supplied on request. Please check the product page or contact us for available sizes and standard compliance.

Care, handling and installation

To maintain corrosion resistance and appearance, handle and store flanges to avoid contamination from carbon steel. After welding, clean weld spatter and heat‑affected zones; passivation may be recommended for critical applications (food, pharma, medical) to restore the protective chromium oxide layer.

Ordering and customisation

If you need specific dimensions, face types, surface finishes or certified material documentation, we can supply standard and bespoke weld neck flanges in stainless steel 1.4404 / 316L. Contact our technical team for assistance with selection, welding guidelines or to request a quotation and material certificates.