ASTM B111 ASME SB 111 C68700 Aluminum Brass Seamless Tubes Tubing

GNEE supplies ASTM B111 C68700 Aluminum Brass "Arsenical" tubes conforming to UNS CDA101, ASTM B111, ASTM B395, ASTM B187, ASTM B152.

C68700 has especially good corrosion resistance properties in seawater. Tubes are supplied in annealed O61 Temper.

Typical applications include:

Q1: What is C68700 Aluminum Brass?
A: C68700 is an aluminum brass alloy containing 76-79% copper and 1.8-2.5% aluminum, with 0.02-0.06% arsenic added to prevent dezincification in seawater.

Q2: What is the Chinese equivalent of UNS C68700?
A: The Chinese GB/T8890 equivalent of UNS C68700 is HAL77-2. Other equivalents include BS CZ110, JIS C6870, and DIN CuZn20Al2.

Q3: What is the density of C68700?
A: C68700 density is 8.33 g/cm³ (0.301 lb/in³) at 25°C, with Poisson's ratio of 0.34 and elastic modulus of 117 GPa.

Q4: What sizes are available for C68700 tubes?
A: ASTM B111 C68700 tubes are available in OD from 3mm to 70mm and wall thickness from 0.2mm to 5mm. Standard inch sizes: 1/4″ to 1″.

Q5: What is the tensile strength of C68700?
A: UNS C68700 in annealed O61 temper has minimum tensile strength of 345 MPa (50 ksi) and yield strength of 125 MPa (18 ksi) .

Q6: What expansion test is required for C68700?
A: C68700 tubes must withstand 20% expansion of original OD per ASTM B153, with no visible cracking or rupture.

Q7: What is the grain size requirement for C68700?
A: Annealed C68700 tubes require an average grain size of 0.010 to 0.045 mm per ASTM E112 at 75x magnification.

Q8: What is the difference between C68700 and C44300?
A: C68700 (Aluminum Brass) contains 1.8-2.5% Al for seawater impingement resistance. C44300 (Admiralty Brass) contains 1% Sn for general corrosion resistance.

Q9: What is the pneumatic test pressure for C68700?
A: C68700 tubes are tested at 60 psig (400 kPa) minimum internal air pressure for 5 seconds with no leakage.

Q10: What standards apply to C68700 heat exchanger tubes?
A: C68700 tubes comply with ASTM B111, ASME SB111, EN 12451, DIN 1785, BS 2871, JIS H3300, and GB/T8890.

Q11: Why does C68700 contain arsenic?
A: Arsenic (0.02-0.06%) prevents dezincification – selective zinc leaching in seawater that causes tube failure. This extends service life to 10+ years.

Q12: What is the hydrostatic test formula for C68700?
A: P = 2St/(D-0.8t) where S=7000 psi fiber stress. Maximum test pressure is 1000 psi (7.0 MPa) unless specified.

Q13: What is the elastic modulus of C68700?
A: UNS C68700 has an elastic modulus of 117 GPa (16000 ksi) at 25°C, with Poisson's ratio of 0.34.

Q14: What is C68700 used for?
A: C68700 tubes are used for condensers, evaporators, heat exchangers, ferrules, and distiller tubes in power plants, desalination plants, and marine applications.

Q15: What is the difference between C68700 and C70600?
A: C68700 (Aluminum Brass) resists impingement attack in high-velocity seawater. C70600 (90/10 Copper-Nickel) resists general corrosion and biofouling better.

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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