ASME SB111 C68700 Seamless Tube, OD 10-50mm, for Seawater Desalination Condenser
ASME SB111 C68700 Seamless Tube, OD 10-50mm, for Seawater Desalination Condenser
C68700 is an aluminum brass alloy with arsenic addition, specifically designed for harsh environments such as seawater desalination. Its composition (Cu: 76-79%, Al: 1.8-2.5%, As: 0.02-0.06%, Zn: balance) ensures exceptional corrosion resistance in seawater and high thermal conductivity. The arsenic content further enhances resistance to dezincification, a critical feature for long-term durability in marine applications.
The production process of Brass Tube
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Raw Materials
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Melting&Casting
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Extrusion
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Rolling
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Intermediate Heat Treatment 1
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Straightening
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Three-line Drawing
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Acid Washing
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Intermediate Heat Treatment 2
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Two Cascade Drawing
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Cutting&Cleaning
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Eddy Current Test
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Final Heat Treatment
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Packing
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Shipping
Comparison Table of Brass Tube Alloy
|
Implementation Standard |
Alloy Specifications |
|
GB/T 5231 |
HAI 77-2 |
|
HSn70-1, HSn72-1 |
|
|
ASTM B111 |
C68700 |
|
C44300 |
|
|
BS EN12451 |
CuZn20Al2As |
|
CuZn28Sn1As |
|
|
JIS H3300 |
C6870, C6871, C6872 |
|
C44300 |
|
|
AS 1569 |
C68700 |
|
C44300 |
Chemical Composition of Brass Tube Alloys
|
Implementation Standard |
Alloy |
Cu (%) |
Al/Sn (%) |
As (%) |
Fe (%) |
Pb (%) |
Other Impurities (%) |
Zn (%) |
Total Impurities (%) |
|
GB/T 5231 |
HAl77-2 |
76.0-79.0 |
1.8-2.5 (Al) |
0.02-0.06 |
≤0.06 |
≤0.07 |
≤0.07 (Other) |
Balance |
≤0.6 |
|
ASTM B111 |
C68700 |
76.0-79.0 |
1.8-2.5 (Al) |
0.02-0.06 |
≤0.06 |
≤0.07 |
≤0.07 (Other) |
Balance |
≥99.5 (Sum) |
|
ASME SB111 |
|||||||||
|
JIS H3300 |
C6870 |
76.0-79.0 |
1.8-2.5 (Al) |
0.02-0.06 |
≤0.05 |
≤0.05 |
≤0.05 (Other) |
Balance |
- |
|
JIS H3300 |
C6871 |
76.0-79.0 |
1.8-2.5 (Al) |
0.02-0.06 |
≤0.05 |
≤0.05 |
≤0.05 (Other); Si: 0.20-0.50 |
Balance |
- |
|
JIS H3300 |
C6872 |
76.0-79.0 |
1.8-2.5 (Al) |
0.02-0.06 |
≤0.05 |
≤0.05 |
≤0.05 (Other); Ni: 0.20-1.0 |
Balance |
- |
|
BS EN12451 |
CuZn20Al2As (CW702R) |
76.0-79.0 |
1.8-2.3 (Al) |
0.02-0.06 |
≤0.07 |
≤0.05 |
Ni ≤0.1; P ≤0.01; Mn ≤0.1; ≤0.3 (Other total) |
Balance |
- |
|
AS 1569 |
C68700 |
76.0-79.0 |
1.8-2.5 (Al) |
0.02-0.06 |
≤0.06 |
≤0.07 |
≤0.07 (Other) |
Balance |
- |
|
GB/T 5231 |
HSn70-1 |
69.0-71.0 |
0.8-1.3 (Sn) |
0.03-0.06 |
≤0.10 |
≤0.05 |
≤0.05 (Other) |
Balance |
≤0.3 |
|
GB/T 5231 |
HSn72-1 |
70.0-73.0 |
0.9-1.2 (Sn) |
0.02-0.06 |
≤0.06 |
≤0.07 |
≤0.07 (Other) |
Balance |
≤0.4 |
|
ASTM B111 |
C44300 |
70.0-73.0 |
0.9-1.2 (Sn) |
0.02-0.06 |
≤0.06 |
≤0.07 |
≤0.07 (Other) |
Balance |
≥99.6 (Sum) |
|
ASME SB111 |
|||||||||
|
JIS H3300 |
C4430 |
70.0-73.0 |
0.9-1.2 (Sn) |
0.02-0.06 |
≤0.05 |
≤0.05 |
≤0.05 (Other) |
Balance |
- |
|
BS EN12451 |
CuZn28Sn1As (CW706R) |
70.0-72.5 |
0.9-1.3 (Sn) |
0.02-0.06 |
≤0.07 |
≤0.05 |
Ni ≤0.1; P ≤0.01; Mn ≤0.1; ≤0.3 (Other total) |
Balance |
- |
|
AS 1569 |
C44300 |
70.0-73.0 |
0.8-1.2 (Sn) |
0.02-0.06 |
≤0.06 |
≤0.07 |
≤0.07 (Other) |
|
Primary Applications in Seawater Desalination
-
Heat Exchangers and Condensers
- C68700 tubes are widely used in multi-stage flash (MSF) and reverse osmosis (RO) systems. Their high thermal conductivity (64 BTU·in/(hr·ft²·°F)) ensures efficient heat transfer between seawater and desalination equipment
- The seamless structure eliminates weld seams, reducing leakage risks in high-pressure environments
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Corrosion Resistance
- The aluminum content forms a protective oxide layer, while arsenic prevents dezincification. This combination allows the tubes to withstand saltwater, chlorine, and sulfide exposure, even at high flow velocities
- Example: In seawater intake pipelines, C68700 resists pitting and crevice corrosion, extending equipment lifespan
-
Mechanical Performance
- Tensile Strength: 345–600 MPa (minimum 345 MPa for annealed tubes)
- Yield Strength: 125–540 MPa, suitable for high-pressure condensers and evaporators.
- Fatigue Resistance: Maintains structural integrity under cyclic thermal and mechanical stresses.
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