ASTM B111 C68700 Seamless Aluminum Brass

GNEE brings forth an exhaustive gamut of Aluminum Brass Tubes which are preferred across the globe owing to their superior quality, durability, and accurate dimensions. The tubes are manufactured using cutting edge techniques and excellent quality raw materials procured from trusted vendors.

To ensure confirmation with ISO standards, the entire range of Aluminum Brass Tubes is examined by adroit quality controllers before final delivery. Clients can purchase these tubes at industry leading prices.

Excellent resistance to seawater and brine corrosion

High thermal conductivity for heat exchange efficiency

Robust mechanical properties (340 MPa tensile strength min)

Customizable in size and finish

Available in soft (O) or hard (H) temper

Multiple end finishes: plain, beveled, or threaded

C68700 Aluminum Brass is preferred when components will be exposed to aggressive marine or brine conditions, or where heat exchange efficiency and longevity are critical. Its aluminum content enhances corrosion resistance beyond many standard brass grades.

Q1: What is ASTM B111 C68700?
A: ASTM B111 C68700 is an aluminum brass alloy containing 76-79% copper and 1.8-2.5% aluminum. It is widely used for seamless condenser and heat exchanger tubes in seawater applications due to its excellent corrosion resistance.

Q2: What is the difference between C68700 and C70600?
A: C68700 (Aluminum Brass) offers superior resistance to impingement attack in high-velocity seawater (up to 3 m/s). C70600 (90/10 Copper-Nickel) provides better resistance to general corrosion and biofouling but is more expensive.

Q3: What is the EN equivalent of UNS C68700?
A: The European equivalent of UNS C68700 is EN CW702R (CuZn20Al2As) . Other equivalents include BS CZ110 (British), DIN 2.0460 (German), and JIS C6870 T (Japanese).

Q4: What is the price of ASTM B111 C68700 tubes?
A: ASTM B111 C68700 seamless tubes are typically priced at 450-550 INR/kg ($5.4-6.6 USD/kg) , depending on quantity, dimensions, and delivery terms. MOQ is usually 500 kg.

Q5: What is the tensile strength of C68700 aluminum brass?
A: UNS C68700 tubes have a minimum tensile strength of 340-345 MPa (50 ksi) and yield strength of 125 MPa (18 ksi) , with minimum 25% elongation in annealed condition.

Q6: Can C68700 tubes be used for seawater?
A: Yes, C68700 aluminum brass tubes are specifically designed for seawater applications including power plant condensers, marine heat exchangers, and desalination plants. The aluminum content forms a protective oxide film that resists saltwater corrosion.

Q7: What sizes are available for C68700 condenser tubes?
A: ASTM B111 C68700 condenser tubes are available in OD from 6mm to 219mm and wall thickness from 1mm to 10mm. Standard lengths are up to 6 meters, with custom lengths available upon request.

Q8: What is the lead time for C68700 tubes from GNEE?
A: GNEE delivers C68700 seamless tubes within 4 weeks for standard orders. Custom sizes or large quantities may require 5-6 weeks. Express delivery is available for urgent projects.

Q9: Why does C68700 contain arsenic?
A: Arsenic (0.02-0.06%) is added to C68700 aluminum brass to prevent dezincification – a selective leaching of zinc that can cause tube failure in seawater. This extends tube service life from months to over 10 years.

Q10: What tests are performed on C68700 heat exchanger tubes?
A: ASTM B111 C68700 heat exchanger tubes undergo hydrostatic testing (leak detection), eddy current testing (surface defects), flattening test, expansion test, and grain size analysis (0.010-0.045 mm).

Q11: Can C68700 tubes be welded or bent?
A: Yes, C68700 aluminum brass tubes can be welded, brazed, soldered, and bent. However, annealing above 650°C is recommended after severe forming to restore corrosion resistance. Seamless tubes are preferred for high-pressure applications.

Q12: What is the thermal conductivity of C68700?
A: UNS C68700 has a thermal conductivity of 58.0 BTU·in/hr·ft²·°F (100.4 W/m·K) at 68°F. This makes it highly suitable for heat exchangers, condensers, and HVAC systems where efficient heat transfer is required.

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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