ASTM B111 C68700 Aluminum Brass Tubes – Heat Exchanger & Condenser Tubing

ASTM B111 C68700 Aluminum Brass Tubes are made from a Copper-Zinc alloy that includes Aluminum and a small amount of Arsenic. This Arsenic serves as an essential inhibitor against dezincification, a form of corrosive attack.

The typical chemical composition of this widely accepted industrial material is:

Copper: 76-79%

Aluminum: 1.8-2.5%

Zinc: Balance

Arsenic: 0.02-0.06%

Iron: 0.05% max

Lead: 0.05% max

The outstanding characteristic of Inhibited Aluminum Brass is its high resistance to impingement attack – a critical factor for tube longevity. This alloy effectively resists the corrosive action of high-velocity salt and brackish water.

Furthermore, this Aluminum Brass Tubing is known for developing a protective, self-healing film around its surface, contributing significantly to its durability and ease of maintenance.

GNEE is a manufacturer and supplier of high-quality Aluminum Brass Seamless Tubes and Aluminum Brass C68700 Tubing manufactured to ASTM B111 standard.

Tubes made from Aluminum Brass are highly recommended for use in applications where cooling water velocities are high, particularly in marine and land power stations where inhibited admiralty brass may fail from impingement.

Key applications include:

Q1: What is ASTM B111 C68700 Aluminum Brass?
A: ASTM B111 C68700 is an aluminum brass alloy (Copper-Zinc-Aluminum) with arsenic addition, used for seamless condenser and heat exchanger tubes in high-velocity seawater applications.

Q2: What is the tensile strength of C68700?
A: C68700 Aluminum Brass has a tensile strength of 414 MPa (60 ksi) and yield strength of 186 MPa (27 ksi) with 55% elongation.

Q3: What is the purpose of arsenic in C68700?
A: Arsenic (0.02-0.06%) in C68700 prevents dezincification – selective zinc leaching in seawater – extending tube service life to 10+ years.

Q4: What is the self-healing property of C68700?
A: C68700 Aluminum Brass develops a protective self-healing film on its surface in seawater, contributing to durability and reduced maintenance.

Q5: What is the difference between C68700 and C44300?
A: C68700 (Aluminum Brass) handles high-velocity seawater (up to 3 m/s). C44300 (Admiralty Brass) fails at velocities above 2 m/s due to impingement attack.

Q6: What sizes are available for C68700 tubes?
A: ASTM B111 C68700 tubes are available in OD from 4.76mm to 104.78mm, wall thickness from 0.508mm minimum, and length up to 15 meters.

Q7: What are the equivalent grades of C68700?
A: UNS C68700 equivalents are Werkstoff NR. 2.0460 (German) and ASTM B111 standard. European equivalent is EN CW702R (CuZn20Al2As) .

Q8: Where are C68700 tubes used?
A: C68700 tubes are used in power plant condensers, desalination plants, evaporators, heat exchangers, refineries, offshore oil rigs, and shipbuilding.

Q9: What is the price of C68700 tubes?
A: C68700 tubes are priced from $10.60-10.75 USD per piece for standard sizes like 11mm OD x 0.80mm WT. Contact GNEE for bulk pricing.

Q10: What is the density of C68700?
A: UNS C68700 has a density of 8.33 g/cc (0.301 lb/in³).

Q11: What is impingement attack resistance?
A: Impingement attack is corrosion caused by high-velocity water disrupting the protective film. C68700 resists this due to its aluminum content forming a durable, self-healing oxide layer.

Q12: Can C68700 tubes be used for offshore oil rigs?
A: Yes, C68700 tubes are widely used in offshore oil rigs for seawater cooling systems, firewater lines, and heat exchangers due to their excellent saltwater corrosion resistance.

Q13: What tempers are available for C68700?

A: C68700 tubes are available in HH, H, O (annealed), QH, and O61 tempers. The most common is O61 (annealed) per ASTM B111.

Q14: Does GNEE supply custom sizes of C68700 tubes?
A: Yes, GNEE supplies custom C68700 tubes including square, rectangular, and hydraulic forms. Contact GNEE with your specifications.

Q15: What is the maximum length for C68700 tubes?
A: GNEE supplies C68700 tubes up to 15 meters straight length. Longer lengths may be available upon special request.

GNEE offers comprehensive secondary fabrication services for ASTM B111 C68700 aluminum brass tubes to meet custom project requirements. Our in-house processing capabilities include: precision cutting (to specified lengths with burr-free ends), tube bending (mandrel and compression bending for tight radii without kinking), flaring and flanging (for secure joint connections), threading (male and female threads per standard specifications), brazing (assembly of tube-to-fitting joints for heat exchanger bundles), and tube expanding (for installing tubes into tube sheets of condensers and heat exchangers). These value-added services reduce customer lead times and eliminate the need for third-party fabrication.

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

GNEE operates a state-of-the-art manufacturing facility equipped with advanced machinery for producing ASTM B111 C68700 aluminum brass tubes. Our production line includes: induction melting furnaces (for precise alloy composition control), horizontal and vertical continuous casting machines (for billet production), extrusion presses (up to 2500 tons for tube forming), cold drawing benches (multiple lines for OD from 4mm to 100mm), pilger mills (for high reduction seamless tube rolling), roller straightening machines, annealing furnaces (controlled atmosphere for O61 temper), and automatic cutting and end-deburring machines. Our annual production capacity exceeds 5,000 tons of copper alloy seamless tubes.

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