Stainless Steel Weld Neck Flanges

Stainless Steel Weld Neck Flanges offer unmatched performance, durability, and safety in demanding industrial applications. Whether used in petrochemical plants, offshore drilling, or high-pressure pipelines, these flanges deliver reliable performance and long-term value. 

Stainless Steel Weld Neck Flanges (also known as SS WN Flanges) are one of the most widely used forged flange types in piping systems where high-pressure, high-temperature, and corrosive environments are involved. Designed with a long tapered hub that provides an excellent connection between pipes and flanges, these components are known for their superior stress distribution, leak-proof connection, and durability.

Weld Neck Flanges are ideal for applications that require frequent bending, twisting, and handling of pipelines. They are butt-welded to the pipe, ensuring structural integrity and reducing turbulence and erosion inside the pipeline. Industries such as oil & gas, petrochemicals, chemical processing, power generation, pharmaceuticals, and marine engineering rely heavily on stainless steel weld neck flanges for secure and efficient operations.

Key Features of Stainless Steel Weld Neck Flanges

• Leak-proof connection: Butt-welded to the pipe, minimizing the risk of leakage.
• High strength and durability: Capable of withstanding extreme pressure and temperature.
• Smooth flow: Bore alignment reduces pressure drops and turbulence.
• Versatile usage: Suitable for high-pressure, sub-zero, and elevated-temperature applications.
• Long service life: Superior resistance to corrosion and wear in aggressive environments.

Types of Stainless Steel Weld Neck Flanges

1. Standard Weld Neck Flanges

Commonly used in general piping systems, suitable for both high- and low-pressure conditions.

2. Long Weld Neck Flanges

Designed with an extended hub, these flanges are used in high-pressure vessel applications and heat exchanger nozzles.

3. Reducing Weld Neck Flanges

Allow connection of pipes with different diameters while maintaining smooth flow and structural strength.

Applications of Stainless Steel Weld Neck Flanges

• Oil and gas pipelines
• Petrochemical plants
• Power generation facilities
• Shipbuilding and marine engineering
• Water treatment plants
• Food processing and pharmaceuticals
• High-pressure and high-temperature piping systems

Materials and Grades Available

Stainless steel weld neck flanges are manufactured using a wide range of stainless steel grades to meet diverse industrial requirements. Some of the commonly used materials and grades include:

Austenitic Stainless Steel:

• SS 304 / 304L
• SS 316 / 316L / 316Ti
• SS 321 / 321H
• SS 347 / 347H

Ferritic Stainless Steel:

• SS 409 / 409M
• SS 410 / 410S
• SS 430

Martensitic Stainless Steel:

• SS 420 / 420J1 / 420J2
• SS 440A / 440B / 440C

Duplex & Super Duplex Stainless Steel:

• UNS S31803 / S32205 (Duplex 2205)
• UNS S32750 / S32760 (Super Duplex)

Precipitation Hardening Stainless Steel:

• 17-4PH
• 15-5PH

These grades are selected based on their specific corrosion resistance, strength, and application suitability.

Advantages of Choosing Stainless Steel Weld Neck Flanges

• High Pressure & Temperature Capability – Perfect for critical process conditions.
• Corrosion Resistance – Superior resistance to chemicals, seawater, and other corrosive agents.
• Longevity – Long service life reduces maintenance and replacement costs.
• Enhanced Safety – Leak-proof design prevents hazardous fluid leakage.
• Wide Availability – Available in multiple sizes, pressure ratings (150#, 300#, 600#, 900#, 1500#, and 2500#), and standards (ANSI, ASME, DIN, JIS, BS, EN).

Manufacturing Standards and Dimensions

• Stainless steel weld neck flanges are manufactured as per international standards such as:
• ASME/ANSI B16.5 – For pipe sizes NPS ½” to 24”
• ASME B16.47 – For larger sizes
• DIN, EN, JIS, BS, and ISO standards