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

Product Specification

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.