B111 C68700 (Aluminum Brass Tube)

B111 C68700 aluminum brass tubes are widely used in seawater desalination plants, power stations, heat exchangers, condensers, evaporators, distillers, refrigeration systems, petroleum industry, and air conditioner applications.

C68700 seamless aluminum brass tubes have especially good corrosion resistance properties in seawater and high-velocity brackish water environments.

We successfully supplied ASTM B111 C68700 aluminum brass tubes to a customer in India for shell & tube condenser applications. During the project, the customer visited our facility for production inspection and quality verification. All tubes were manufactured in accordance with ASTM B111 requirements and delivered with complete Material Test Certificates (MTC), ensuring full heat number traceability and verified chemical and mechanical properties.

C68700 aluminum brass tubes are pressed and drawn seamless tubes. The aluminum brass tube is:

Light in weight

Good in thermal conductivity

High in low-temperature strength

These tubes are specially adapted to resist corrosion by both saltwater and brackish water. They resist the action of high-velocity salt and brackish water, making them commonly used for condenser tubes in marine and land power stations where cooling water velocities are high.

The main characteristic of C68700 is its high resistance to impingement attack.

Additionally, copper tubes and copper alloy tubes (including C68700) are widely used in:

Air conditioner systems

Heat exchangers

Refrigeration equipment

Petroleum industry

Power stations

Small diameter copper tubes are often used to transport pressurized liquids and as pressure tubes for meters. Brass pipes are sturdy and corrosion-resistant, making them the first choice for modern contractors in the installation of water pipes, heating pipes, and cooling pipes in residential and commercial buildings. Brass pipes are the best water supply pipe.

1. What is the difference between ASTM B111 C68700 (Aluminum Brass) and ASTM B111 C70600 (Copper-Nickel)?

ASTM B111 C68700 is an aluminum brass alloy with 76-79% copper and 1.8-2.5% aluminum, offering excellent resistance to high-velocity seawater impingement. ASTM B111 C70600 is a 90/10 copper-nickel alloy, preferred for superior resistance to general seawater corrosion and biofouling. For condenser tubes in power plants with high-velocity cooling water, choose C68700; for marine piping systems, choose C70600.

2. What is the European equivalent (EN standard) for UNS C68700 aluminum brass tubes?

The closest European equivalent for UNS C68700 is EN CW702R (CuZn20Al2As). This aluminum brass grade is also used for heat exchanger tubes and condenser tubes in seawater applications across European standards.

3. Can ASTM B111 C68700 seamless tubes be welded and bent for custom heat exchanger designs?

Yes, ASTM B111 C68700 seamless tubes can be fabricated using cold working, hot working, bending, forming, and welding. Proper annealing above 650°C is recommended after severe forming to restore corrosion resistance for heat exchanger and evaporator tube applications.

4. What is the maximum operating temperature for C68700 condenser tubes in a power plant?

C68700 condenser tubes have an ideal working temperature range of 760°C to 871°C. However, for continuous service in condenser and heat exchanger applications, temperatures below 200°C are typical to maintain mechanical integrity and corrosion resistance.

5. What is the lead (Pb) content in B111 C68700 distiller tubes, and is it RoHS compliant?

B111 C68700 distiller tubes have a maximum lead content of 0.07% (0.07% max). This meets RoHS requirements for distiller tubes, evaporator tubes, and heat exchanger tubes used in food processing and water treatment applications.

6. What quality tests are performed on ASTM B111 C68700 heat exchanger tubes?

Standard quality tests for ASTM B111 C68700 heat exchanger tubes include: expansion test (determines expansion limit), flattening test (analyzes resistance to flattening), hydrostatic test (checks for leakages), nondestructive test (Eddy current) , and residual stress test (determines durability under working stress).

7. What is the minimum order quantity (MOQ) for UNS C68700 aluminum brass seamless tubes?

For UNS C68700 aluminum brass seamless tubes in standard sizes (e.g., 19mm OD x 1.5mm wall), MOQ can be as low as 500 kg. Contact GNEE for specific project requirements and custom sizes.

8. What is the thermal conductivity of C68700 aluminum brass alloy?

The thermal conductivity of C68700 aluminum brass alloy is 100.4 W/m-K at 20°C. This makes C68700 tubes highly suitable for heat exchangers, condensers, and evaporators requiring efficient heat transfer.

9. What is the difference between B111 C68700 and B111 C44300 (Admiralty Brass) for seawater condenser tubes?

B111 C68700 (Aluminum Brass) has higher aluminum content (1.8-2.5%) and offers superior resistance to impingement attack in high-velocity seawater compared to B111 C44300 (Admiralty Brass) , which contains arsenic and tin. For power plant condensers with cooling water velocities above 2.5 m/s, C68700 is preferred over C44300.

10. Can GNEE provide third-party inspection (e.g., BV, SGS, TUV) for B111 C68700 tubes?

Yes, GNEE can arrange third-party inspections (e.g., BV, SGS, TUV, Lloyds) for all B111 C68700 products, including condenser tubes, heat exchanger tubes, and evaporator tubes. Inspection can include chemical analysis, mechanical testing, dimensional checks, and hydrostatic testing before shipment.

Every tube in this lot has passed third-party witnessed inspection per ASTM B111 standard for C68700 alloy. Below are actual photos from customer-onsite inspection, including eddy current testing and dimensional verification.

Inspection items verified:
• Eddy current testing (ECT) – no through-wall defects
• Outer diameter & wall thickness – within ±0.02mm tolerance
• Surface finish & temper (O61) – conforms to ASTM
• Hardness & chemical composition – certified.

After passing inspection, all tubes are packed according to export standards and customer-specific requirements. The packing process is documented below to ensure traceability and damage-free delivery.

Packing steps shown in video & images:
1. Tube cleaning & drying
2. Plastic end caps on both ends
3. VCI anti-rust paper wrapping
4. Bundle strapping with moisture barrier film
5. Plywood wooden case (ISPM-15 compliant) with foam padding
6. Labeling with ASTM grade, lot number, and inspection stamp

All ASTM C68700 tubes are produced and inspected on our in-house equipment, allowing full process control from billet casting to final packing.

Key equipment used for this lot:
• Induction melting furnace – precise alloying (Cu + Zn + Al + As)
• Horizontal continuous casting – uniform billet structure
• Extrusion press (800T / 1630T) – seamless tube forming
• Cold drawing bench (5–40m) – dimensional accuracy to ±0.02mm
• Online eddy current tester (FOERSTER / MAC) – 100% NDT
• Ultrasonic wall thickness gauge – real-time monitoring
• Annealing furnace (controlled atmosphere) – temper O61

In-house metrology: Micrometers, pin gauges, optical comparator, hardness tester (HV/HRB)

All equipment is calibrated quarterly. Production records are traceable by lot number.

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