Copper Nickel Long Welding Neck Flange ASTM B466 UNS C71500 ASME B16.5

Copper Nickel Long Welding Neck Flange ASTM B466 UNS C71500 ASME B16.5

1. Product Description

This product is a Long Welding Neck Flange (LWNF) manufactured from UNS C71500 (70/30 Copper-Nickel alloy / CuNi 70/30) in accordance with ASTM B466 and ASME B16.5 standards. Also known as CuNi 70/30 or Werkstoff Nr. 2.0882, this alloy contains approximately 70% copper and 30% nickel, with small additions of iron and manganese to enhance strength and corrosion resistance. The Long Welding Neck Flange features an extended, heavy-wall neck that provides additional reinforcement in high-stress applications. Unlike a standard Weld Neck flange, the LWNF is constructed in two sections: the upper section is a heavy-wall barrel, while the lower section is a disc-like plate flange with all dimensions conforming to ASME B16.5 standard flanges. This flange is designed for butt-weld connection to piping systems and is primarily applied to the construction of pressure vessels functioning as nozzles (such as thermowell nozzles).

2. Key Product Parameters

3. Application / Usage

This Long Welding Neck Flange is ideal for seawater and corrosive fluid systems in demanding environments:

• Pressure Vessels & Boilers: Nozzle connections, thermowell nozzles

• Offshore Oil & Gas: Platform piping, subsea applications, seawater injection systems

• Marine & Shipbuilding: Seawater cooling systems, firewater lines, offshore fire water systems

• Desalination Plants: High-pressure seawater intake, brine recirculation lines

• Power Generation: Condenser cooling water systems, heat exchangers

• Chemical Processing: Chloride-containing environments where stainless steel may suffer SCC

4. Advantages

• Extended Neck Design: The heavy-wall barrel provides additional reinforcement and stress distribution in high-stress applications, making it ideal for pressure vessel nozzles

• Superior Corrosion Resistance: Exceptional resistance to seawater, pitting, crevice corrosion, and chloride stress corrosion cracking

• Higher Strength: 70/30 CuNi offers better strength and erosion resistance than 90/10 CuNi

• Biofouling Resistance: Copper content naturally inhibits marine biological growth

• Excellent Weldability: Single-phase alpha structure enables outstanding fabrication properties

• Insulation Clearance: Extended neck provides clearance for insulation in process plant applications

5. Functions

The Long Welding Neck Flange provides a permanent, reinforced bolted connection point for joining piping systems to pressure vessels, boilers, and heat exchangers. The extended heavy-wall neck is butt-welded to the pipe or vessel nozzle, forming a unified structure that distributes stress evenly and minimizes pressure concentration at the joint. The flange face accommodates a gasket to ensure a reliable seal when bolted to a mating flange. Unlike standard Weld Neck flanges, the long type is unsuitable for pipes and is primarily used in process plant applications.

6. Installation Instructions

1. Unpacking Inspection: Check for transit damage; verify markings, dimensions, and pressure class per ASME B16.5

2. Surface Preparation: Clean the weld bevel and adjacent area using dedicated tools; remove all oil, grease, and contaminants

3. Alignment: Accurately align the flange neck with the pipe or vessel nozzle, ensuring proper fit-up

4. Welding: Perform butt-weld following approved WPS with certified welders. Use GTAW (TIG) process with matching filler metal. Preheat generally not required; interpass temperature ≤150°C. No post-weld heat treatment required

5. Gasket Installation: Place a suitable gasket (e.g., spiral wound, PTFE) on the flange face

6. Bolting: Install bolts and tighten in a cross-torque sequence to the recommended torque value

7. Hydrotest: Test pressure = 1.5 × design pressure; ambient temperature not below 5°C

7. Precautions

• Cleanliness: Requires a higher degree of cleanliness than carbon steel fabrication; use dedicated tools to prevent contamination

• Temperature Limit: For aqueous corrosion service, verify system conditions for temperatures above 300°C

• Welding Heat Input: CuNi puddle is sluggish with an oxide film; requires appropriate amperage control

• Medium Compatibility: Not recommended for use with strong oxidizing acids (e.g., nitric acid) or ammonia systems

• Bolting Torque: Do not exceed recommended torque to prevent gasket damage or flange distortion

• Gasket Selection: Choose gasket material compatible with the service medium and pressure/temperature conditions

8. Shipping & Delivery

• Standard delivery time is typically 15–30 days, subject to order quantity, pressure class, and specification availability

9. Payment Terms

• Common international payment methods include T/T (Telegraphic Transfer) and L/C at sight (Letter of Credit)

10. Packaging

• Products are securely packed in plywood cases or wooden crates with internal cushioning to ensure safe transportation and prevent damage during transit

11. After-Sales / Return & Warranty Policy

• All products undergo strict quality inspection before shipment, with Mill Test Certificates (EN 10204 3.1/3.2) available

• PMI and third-party inspection (ABS, DNV, CCS, LR, BV, etc.) available upon request

• In case of quality issues, retain original packaging and provide relevant photos or third-party inspection reports

• Specific return, exchange, and warranty terms are subject to the final sales contract agreement.

FAQ

1. Are you trading company or manufacturer ?
    We are manufacturer ,You can see the certification.
2. How long is your delivery time?
    Generally it is 5-10 days if the goods are in stock. or it is 15-20 days if the goods are not in stock, it is according to quantity.
3. Do you provide samples ? is it free or extra ?
    Yes, we could offer the sample for free charge but need pay the cost of freight.
4. What is your terms of payment ?
    Payment<=1000USD, 100% in advance. Payment>=1000USD, 50% T/T in advance ,balance before shippment.