Copper Nickel Butt Welding Cap ASTM B466 UNS C70600 8" ASME B16.9

1. Product Description

This product is a butt-welding pipe cap manufactured from UNS C70600 (90/10 Copper-Nickel alloy / CuNi 90/10) in accordance with ASTM B466 and ASME B16.9 standards. Also known as CuNi10Fe1.6Mn or Werkstoff Nr. 2.0872, this alloy consists of approximately 90% copper and 10% nickel, with small additions of iron and manganese to enhance strength and corrosion resistance. A pipe cap is a dome-shaped or ellipsoidal closure fitting welded directly to the pipe end with a full-penetration butt weld, providing a permanent seal. This 8" fitting is designed for permanent butt-weld connection to terminate the end of a piping system in demanding marine and industrial applications.

2. Key Product Parameters

3. Application / Usage

This butt-welding cap is ideal for seawater and corrosive fluid systems where permanent pipe termination is required:

• Marine & Shipbuilding: Seawater cooling systems, firewater lines, ballast systems, ship hull fittings

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

• Desalination Plants: Seawater intake headers, brine discharge lines

• Power Generation: Condenser cooling water systems, heat exchangers

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

• Hydrostatic Testing: Temporary sealed ends for pressure testing (caps may be cut off later)

4. Advantages

• Superior Seawater Corrosion Resistance: Exceptional resistance to pitting, crevice corrosion, and stress corrosion cracking in marine environments. Long-term corrosion rates decrease continuously to below 2.5 µm/yr

• Biofouling Resistance: Naturally forms a protective oxide layer that resists marine biological growth

• Excellent Weldability: Single-phase alpha structure enables outstanding fabrication properties without complex preheating or post-weld heat treatment

• Cost-Effective: Offers favorable balance of performance and cost compared to 70/30 CuNi, titanium, or super duplex grades

• Permanent Seal: Full-penetration butt weld provides a leak-proof, permanent closure with high structural integrity

• Low Maintenance: Long service life with minimal upkeep; ideal for systems where access is difficult

5. Functions

The butt-welding cap provides a permanent, leak-proof closure for the end of a pipe in a piping system. It is welded directly to the pipe end with a full-penetration butt weld, forming a dome-shaped or ellipsoidal seal that completely blocks fluid flow. Unlike removable closures such as blind flanges, a pipe cap is a permanent fitting that requires cutting to remove. It is commonly used to terminate pipelines permanently, seal pipe ends during hydrostatic testing, or close off unused branches in a piping network.

6. Installation Instructions

1. Unpacking Inspection: Check for transit damage; verify markings, dimensions, and material certification per ASME B16.9

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

3. Alignment: Accurately align the cap with the pipe end, ensuring proper fit-up. The cap material must match the pipe material to avoid galvanic corrosion

4. Tack Welding: Apply minimum tack welds to hold the cap in position; clean thoroughly before final welding

5. Welding: Perform full-penetration butt weld following approved WPS with certified welders. Use GTAW (TIG) process with matching ERCuNi filler wire (AWS A5.7). Use 100% argon shielding; back purge recommended for root pass. Preheat generally not required; interpass temperature ≤150°C. No post-weld heat treatment required

6. Post-Weld: Clean weld area; perform NDT (PT/MT, UT) as per project requirements

7. Hydrotest (if applicable): 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 stainless steel tools

• 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 and technique

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

• Material Matching: Cap material must match the pipe material to prevent galvanic corrosion and code violations

• Permanent Closure: Unlike blind flanges, pipe caps are permanent and require cutting to remove

8. Shipping & Delivery

• Standard delivery time is typically 15–30 days, subject to order quantity, wall thickness, 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

• 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.

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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.