Weld Neck Flanges

Leaks and fatigue failures often occur at high-pressure joints with repeated loading. Our Weld Neck Flanges reduce these issues through full penetration welding and hub-based stress transfer.

Standard Specification

ASME B16.5, ASME B16.47, EN 1092-1, DIN 2576, ANSI, API 6A, MSS SP-44

Pressure Rating

Class 150, 300, 600, 900, 1500, 2500 (PN6 to PN100 for EN standards)

Material

Carbon Steel (ASTM A105), Stainless Steel (ASTM A182 F304/F316), Alloy Steel (ASTM A694 F52)

Nominal Size

½” to 60″ (DN15 to DN1500) [Custom sizes up to 120″ (DN3000) available]

Flange Type

Weld Neck (Integral Hub)

Product Description

Leaks and fatigue failures often occur at high-pressure joints with repeated loading. Our Weld Neck Flanges reduce these issues through full penetration welding and hub-based stress transfer.

Facing Type

Raised Face (RF), Flat Face (FF), Ring-Type Joint (RTJ)

Dimensions

Customizable (OD, Thickness, Hub Length)

Bolt Circle Diameter

ASME B16.5: Standardized per class/size; EN 1092-1: Metric series

Number & Size of Bolt Holes

4 to 48 holes (½” to 1¼” bolts, custom patterns available)

Surface Finish

Smooth machined (125–250 RA), Serrated (Stock/Spiral finish)

Corrosion Resistance

SS316: High resistance; Carbon Steel: Epoxy-coated/galvanized

Temperature Rating

-29°C to +540°C (A350 LF2 for cryogenic)

Material Certification

MTR, EN 10204 3.1/3.2, PED 2014/68/EU, NACE MR0175

Gasket Compatibility

Spiral-wound, RTJ, or flat gaskets

Coating/Plating

HDG, Xylan, PTFE, Electroless Nickel

Manufacturing Method

Forged (ASTM A105/A182), Cast (A216 WCB), Machined (SA516)

Technical Advantages

Pipelines in high-load or vibration-prone zones need strong weldable joints. We offer forged flanges with integral hubs to handle stress without thinning the neck. 
Facing types include RF, FF, and RTJ, compatible with spiral-wound or RTJ gaskets. Each unit is machined to specified OD, hub height, and bolt pattern.

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Need reliable Flanges for your next project? Get in touch with us today, and we’ll help you find exactly what you need!

Industry Applications

Oil & Gas Industry

Handles up to Class 2500 pressure, ensuring leak-proof sealing for upstream and midstream transport networks. 

Petrochemical Process Plants

Withstands high thermal stress in reactors and distillation lines, supporting ASTM A182 and A694 grades. 

Power Generation Boilers

Suitable for -29°C to +540°C operations, integrating well with A350 LF2 flanges in cryogenic systems.

Desalination and Water Treatment

Supports corrosion-resistant builds like SS316, enabling long service life in chloride-prone environments. 

Marine Ballast Lines

Flanges with epoxy or galvanic coating offer durability under seawater contact and pressure cycling. 

Heavy Industrial Fabrication

Custom sizes up to 120″ help connect large-diameter pipelines in structural and pressure vessel applications. 

Secure Pipe Connections for Long-Term Operation

High-pressure lines need flanges that stay aligned even after thermal cycling and repeated assembly. Our Weld Neck Flanges offer this stability with consistent hub design and tight sealing options. 
Clients can choose from ASTM A105, A182, or A694 grades based on fluid, pressure, and corrosion needs. Each flange meets EN 10204 3.1/3.2 and NACE MR0175 for traceability.

weld neck flanges

Having Doubts? Our FAQ

Check all our Frequently Asked Question

How do Weld Neck Flanges reduce the chance of joint failure in high-stress piping?

Weld Neck Flanges use a tapered hub that transfers stress evenly from flange to pipe. This reduces fatigue from thermal expansion and vibration. Full-penetration welding adds strength at the connection point.

Can I use the same gasket across RF and RTJ face types?

No, RF flanges work with flat or spiral-wound gaskets, while RTJ flanges need metal ring gaskets. Each face type has its own sealing method and material contact design. Matching them incorrectly leads to leakage or gasket damage. 

Do you support specific bolt patterns and material testing needs for project standards?

Yes, we machine bolt holes to match exact project drawings or flange standards. We also offer full material traceability with EN 10204 3.1/3.2 and ultrasonic testing if needed. This ensures your order meets both technical and compliance checks. 

How do I choose between A105, A182, and A694 for my system?

A105 suits general carbon steel lines under moderate pressure. A182 works better for corrosive environments like offshore or chemical plants. A694 supports high-yield service in oil and gas with stronger mechanical properties.

Can these flanges support special coatings or offshore certification?

Yes, we offer coatings like HDG, PTFE, Xylan, or Electroless Nickel for harsh or marine settings. We also follow NACE MR0175 for sour service compatibility. Offshore clients can request additional testing or marking as per site needs.

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LOCATIONS

Global Sales Office

818, Preakness lane, Coppell, Texas, USA – 75019

Registered Office

10-A, First Floor, V.V Complex, Prakash Nagar, Thiruverumbur, Trichy-620013, Tamil Nadu, India.

Operations Office

9/1, Poonthottam Nagar, Ramanandha Nagar, Saravanampatti, Coimbatore-641035, Tamil Nadu, India. ㅤ

Other Locations

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weld neck flanges

Weld Neck Flanges

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weld neck flanges

Weld Neck Flanges

Need reliable Machining for your next project? Get in touch with us today, and we’ll help you find exactly what you need!

Get Latest Price

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