ASTM B111 C68700 Seamless Aluminum Brass Tube
We manufacture and supply ASTM B 111 C68700 seamless aluminum brass tubes for condensers, heat exchangers, evaporators, desalination plants and marine cooling systems.
The tubes can also be supplied in accordance with ASME SB-111/SB-111M, commonly searched as ASME SB111 UNS C68700 seamless tube, when required for ASME pressure equipment and project specifications.
Available products include straight condenser tubes, heat exchanger tubes, evaporator tubes and customized U-bend tubes. Dimensions, temper, testing, certification and packaging can be supplied according to the purchase specification.
ASTM B111 C68700 Tube Specifications
| Item | Specification |
|---|---|
| Product | Seamless aluminum brass tube |
| Material | UNS C68700 |
| Alloy designation | Aluminum Brass, Arsenical |
| ASTM standard | ASTM B111/B111M |
| ASME standard | ASME SB-111/SB-111M |
| Product forms | Straight tube and U-bend tube |
| Typical condition | Annealed or drawn temper as specified |
| Maximum standard diameter | Up to 80 mm OD under ASTM B111/B111M |
| Applications | Condensers, heat exchangers and evaporators |
| Certification | EN 10204 3.1 or as specified |
| Inspection | Mill inspection or third-party inspection |
What Is UNS C68700 Aluminum Brass?
UNS C68700 is a copper-zinc alloy containing controlled additions of aluminum and arsenic.
Aluminum promotes the formation of a protective surface film, improving the material’s resistance to corrosion and erosion in properly designed cooling-water systems. Arsenic is added to improve resistance to dezincification.
C68700 offers a practical combination of:
- Good thermal conductivity
- Good cold-working capability
- Suitable mechanical strength
- Good tube-expansion performance
- Resistance to fresh water and brackish water
- Resistance to flowing seawater under controlled conditions
These properties make C68700 a widely specified tube material for marine condensers, industrial heat exchangers, power plants and seawater desalination equipment.
ASTM B111 vs ASME SB111 C68700 Tube
ASTM B111/B111M is the ASTM specification for copper and copper-alloy seamless condenser tubes and ferrule stock used in condensers, evaporators and heat exchangers.
ASME SB-111/SB-111M is the corresponding ASME material specification used in projects governed by the ASME Boiler and Pressure Vessel Code.
| Requirement | ASTM B111/B111M | ASME SB-111/SB-111M |
|---|---|---|
| Standards organization | ASTM International | ASME |
| Material designation | UNS C68700 | UNS C68700 |
| Product type | Seamless condenser and heat exchanger tube | Seamless condenser and heat exchanger tube |
| Typical project use | Industrial, marine and commercial equipment | ASME boiler and pressure vessel projects |
| Important consideration | ASTM edition and purchase specification | ASME edition and applicable construction code |
The two specifications cover closely corresponding products. However, they should not be described as automatically interchangeable in every project.
The applicable standard edition, design code, certification requirements and purchaser approval must be confirmed before material substitution.
Chemical Composition of C68700
| Element | Content |
|---|---|
| Copper, Cu | 76.0–79.0% |
| Aluminum, Al | 1.8–2.5% |
| Arsenic, As | 0.02–0.06% |
| Iron, Fe | 0.06% maximum |
| Lead, Pb | 0.07% maximum |
| Zinc, Zn | Remainder |
Copper content includes silver where applicable.
The material test certificate should state the actual heat analysis and confirm compliance with the specified material standard.
Typical Physical Properties
The following values are typical material properties and are not acceptance values for every ordered tube condition.
| Property | Typical Value |
|---|---|
| Density | 8.33 g/cm³ |
| Thermal conductivity at approximately 20°C | Approximately 100 W/m·K |
| Electrical conductivity | Approximately 23% IACS |
| Solidus temperature | Approximately 932°C |
| Liquidus temperature | Approximately 971°C |
Tensile strength, yield strength, elongation and grain size depend on the ordered temper, tube dimensions and applicable standard requirements.
Guaranteed mechanical properties should therefore be confirmed against the specified temper and material test certificate.
Advantages of C68700 Aluminum Brass Tube
Good Heat-Transfer Performance
C68700 provides good thermal conductivity for efficient heat transfer in condensers, evaporators and shell-and-tube heat exchangers.
Resistance to Cooling Water
The alloy is suitable for many freshwater, brackish-water and flowing-seawater cooling systems when the operating conditions and water chemistry are properly controlled.
Good Tube-Expansion Capability
Annealed C68700 tubes provide suitable ductility for mechanical expansion into tube sheets during condenser and heat exchanger fabrication.
Balanced Material Cost and Performance
C68700 provides a practical balance between thermal conductivity, corrosion resistance, mechanical strength and material cost.
Good Fabrication Performance
The tubes can be cut, bent, expanded and machined using suitable fabrication procedures. U-bend tubes can also be produced according to the required bend radius and straight-leg dimensions.
Applications of ASTM B111 C68700 Tube
ASTM B111 and ASME SB111 C68700 tubes are commonly used in:
- Surface condensers
- Steam condensers
- Shell-and-tube heat exchangers
- Evaporators
- Distillers
- Seawater desalination systems
- Power plant cooling systems
- Marine engine cooling equipment
- Shipboard condensers
- Offshore cooling systems
- Petrochemical heat exchangers
- Refinery cooling equipment
- Industrial HVAC equipment
Material suitability should be evaluated according to the actual water composition, flow velocity, temperature, suspended solids and equipment design.
C68700 vs C44300, C70600 and C71500
| Grade | Alloy Type | Main Characteristic | Typical Application |
|---|---|---|---|
| C44300 | Admiralty brass | Good heat transfer in moderate cooling-water conditions | General condensers and freshwater systems |
| C68700 | Aluminum brass | Balance of heat transfer, strength and seawater resistance | Marine condensers and desalination equipment |
| C70600 | 90/10 copper-nickel | Improved resistance to aggressive and polluted seawater | Marine cooling and seawater piping |
| C71500 | 70/30 copper-nickel | Higher resistance for demanding marine environments | Offshore and high-duty seawater service |
C68700 should not automatically replace copper-nickel alloys in severe seawater conditions.
For water containing ammonia, sulfides, excessive suspended solids or high levels of pollution, a detailed corrosion assessment should be completed before material selection.
Available Tube Forms
We can supply:
- Seamless straight tubes
- Condenser tubes
- Heat exchanger tubes
- Evaporator tubes
- Distiller tubes
- Cut-to-length tubes
- U-bend heat exchanger tubes
- Tubes manufactured to customized dimensional requirements
Dimensions and Ordering Requirements
The following information should be included in an inquiry:
- ASTM or ASME material standard
- UNS material grade
- Outside diameter
- Wall thickness
- Minimum-wall or average-wall requirement
- Straight length or U-bend configuration
- Temper or grain-size requirement
- Quantity
- Testing requirements
- Inspection certificate
- Third-party inspection requirement
- Packaging and marking requirements
Actual manufacturing availability depends on the requested tube diameter, wall thickness, length, temper and quantity.
Inspection and Testing
Testing can be performed according to the applicable edition of ASTM B111/B111M, ASME SB-111/SB-111M and the agreed purchase specification.
Inspection may include:
- Chemical composition analysis
- Mechanical property testing
- Dimensional inspection
- Visual and surface inspection
- Expansion testing
- Flattening testing
- Residual stress testing
- Grain-size examination
- Eddy-current examination
- Hydrostatic or pneumatic testing
- Material identification
- Final document review
The exact inspection program should be stated in the inquiry because not every test applies to every tube condition or order.
Optional Inspection Services
Additional services can be arranged when specified:
- EN 10204 3.1 inspection certificate
- Positive Material Identification
- Independent third-party inspection
- Customized Inspection and Test Plan
- U-bend dimensional inspection
- Pre-shipment inspection
- Tube cleanliness inspection
Packaging
C68700 seamless aluminum brass tubes can be supplied in export seaworthy packaging, including:
- Reinforced wooden cases
- Waterproof wrapping
- Plastic end protection
- Tube separators
- Customized shipping marks
- Special supports for U-bend tubes
The packaging method can be adjusted according to the tube length, transportation method and destination requirements.
How to Order ASTM B111 C68700 Tube
Ordering Example 1
ASTM B111/B111M UNS C68700 Seamless Aluminum Brass Tube
Size: 25.4 mm OD × 0.7 mm AVG. WT × 3500 mm Length
Condition: Annealed
Product Form: Straight Heat Exchanger Tube
Inspection: Eddy-Current Examination
Certificate: EN 10204 3.1
Quantity: As specified
Ordering Example 2
ASME SB-111/SB-111M UNS C68700 Seamless Tube
Size: 25.4 mm OD × 0.7 mm AVG. WT × 3500 mm Length
Application: Condenser Tube
Testing and Certification: According to the project specification
ASME-SB111-UNS-C68700-condenser-tube-supplier
Frequently Asked Questions
What standard covers C68700 seamless condenser tubes?
ASTM B111/B111M covers copper and copper-alloy seamless tubes and ferrule stock for condensers, evaporators and heat exchangers. UNS C68700 is one of the alloys included in this specification.
Is ASTM B111 C68700 the same as ASME SB111 C68700?
ASME SB-111/SB-111M is the corresponding ASME material specification for this product category. The technical requirements are closely related, but the applicable standard edition, ASME construction code and project requirements must be confirmed before substitution.
Is C68700 suitable for seawater?
C68700 is commonly used in flowing seawater and marine cooling systems. Suitability depends on water velocity, temperature, ammonia, sulfides, suspended solids, chlorination and shutdown conditions.
What is the difference between C68700 and C70600?
C68700 aluminum brass generally provides higher thermal conductivity and a competitive material cost. C70600 90/10 copper-nickel generally provides better resistance in aggressive, polluted or high-duty seawater conditions.
Can C68700 tubes be supplied in annealed condition?
Yes. Annealed C68700 tubes can be supplied when required for tube expansion, bending or heat exchanger fabrication. The required temper or grain-size condition should be included in the purchase specification.
Can C68700 U-bend tubes be supplied?
Yes. U-bend tubes can be manufactured according to the specified outside diameter, wall thickness, straight-leg length, bend radius, heat treatment and inspection requirements.
Related ASTM B111 Tube Grades
- ASTM B111 C44300 Admiralty Brass Tube
- ASTM B111 C70600 90/10 Copper-Nickel Tube
- ASTM B111 C71500 70/30 Copper-Nickel Tube
- ASTM B111 Copper and Copper-Alloy Tube Grades
For quotation, provide the required standard, material grade, outside diameter, wall thickness, length, quantity, temper, testing and certification requirements.
