C70600 vs Titanium for Heat Exchanger Tubes

Titanium wins on pure performance. It does not corrode in seawater. Not at high velocity. Not at high temperature. Not in sand. Not in sulfides. C70600 cannot match that. But titanium costs 3-5 times more. So the real question is： does your heat exchanger need titanium performance? Or is C70600 good enough? For most seawater heat exchangers, C70600 is good enough. For the tough ones, you need titanium.

Use C70600 for normal seawater heat exchangers. Use titanium when velocity exceeds 4 m/s, temperature exceeds 80°C, or sand is present.

Where C70600 works fine：

Velocity under 2.5 m/s

Temperature under 60°C

Clean seawater, no sand

Normal marine and power plant heat exchangers

Where you need titanium：

Velocity over 4 m/s

Temperature over 80°C

Sand or abrasive particles in the water

Sulfides present (polluted harbors, certain industrial discharges)

Titanium typically costs 3 to 5 times more than C70600. Here is a rough comparison.

But price per kg is not the whole story. Titanium is also lighter (density 4.51 vs 8.94 g/cm³). So for the same dimensions, a titanium tube weighs half as much. Cost per meter is still higher, but the gap is smaller than per kg.

Example for 3/4" OD x BWG 18 tube (1 meter)：

C70600 weight： 0.49 kg. Cost at 4/kg：4/kg：1.96

Titanium weight： 0.25 kg. Cost at 16/kg：16/kg：4.00

Titanium is still about 2x more per meter

You spend the extra money when C70600 will fail. Here are the conditions that kill C70600.

Condition 1： High velocity

C70600 limit is 2.5-3.0 m/s

Above that, impingement corrosion eats the tube inlet

Titanium handles 10+ m/s with no problem

Condition 2： High temperature

C70600 limit is 60°C for seawater

Above that, corrosion rate doubles every 10°C

Titanium works fine at 100-150°C

Condition 3： Sand or abrasives

Sand erodes C70600

Titanium is much harder and resists erosion

Condition 4： Sulfides (polluted water)

Sulfides kill C70600 quickly

Titanium does not care

Condition 5： Long life requirement (30+ years with zero failures)

C70600 will eventually corrode

Titanium will outlast the heat exchanger

Use C70600 when：

Seawater velocity is under 2.5 m/s

Seawater temperature is under 60°C

Water is clean (no sand, no sulfides)

You are okay with 20-30 year tube life

Upfront budget matters

Real world examples where C70600 is perfect：

Shipboard coolers (velocity 1.5-2.0 m/s, temp 30-40°C)

Coastal power plant condensers (velocity 2.0-2.5 m/s, temp 25-35°C)

Offshore platform fire water lines (intermittent flow)

Desalination low temperature evaporators

Titanium is harder to work with. C70600 is easier to roll, weld, and replace.

What this means for your maintenance team：

C70600 tubes can be replaced by any competent tube worker

Titanium requires training, special tools, and clean conditions

If you do not have titanium experience, you will struggle

Q1： Which is better for heat exchanger tubes, C70600 or titanium?

Titanium is better on corrosion resistance. C70600 is better on cost. Titanium lasts almost forever in seawater. C70600 lasts 20-30 years. For most heat exchangers, 20-30 years is enough. Spending 2-3x more for titanium is hard to justify unless you have aggressive conditions (high velocity, high temperature, sand, sulfides).

Q2： Does titanium cost more than C70600?

Yes, titanium typically costs 2-3x more per meter for heat exchanger tubes. The raw material price per kg is 3-5x higher. But titanium is half the density, so you buy fewer kg. Still, a titanium tube bundle costs about twice as much as a C70600 bundle. For a large condenser, that can be hundreds of thousands of dollars difference.

Q3： How long does C70600 last in a seawater heat exchanger compared to titanium?

C70600： 20-30 years. Titanium： 50+ years. Most heat exchangers are replaced or retubed every 20-30 years anyway. So the extra life of titanium may not matter. If your plant plans to run for 50 years without major maintenance, titanium makes sense. For normal replacement cycles, C70600 is long enough.

Q4： When should I choose titanium instead of C70600?

Choose titanium when C70600 will fail. That means velocity over 3 m/s, temperature over 60°C, sand in the water, or sulfides present. Also choose titanium if you cannot afford any tube failure ever (nuclear safety systems, some offshore production). Otherwise, C70600 is fine.

Q5： Can I mix C70600 and titanium in the same heat exchanger?

Not recommended. They have different galvanic potentials. In seawater, the less noble metal (C70600) will corrode faster near the titanium. If you need to use both, isolate them electrically. Use a non‑conductive gasket or a spool piece. Most engineers avoid mixing.

Q6： Which material is easier to roll into a tube sheet?

C70600 is easier. It is softer and more forgiving. Titanium is springy. It resists deformation. You need more rolling torque. The tube sheet holes must be cleaner. The rolling tools must be in better condition. If your tube shop has never rolled titanium before, expect a learning curve.

Q7： Does titanium have any disadvantages compared to C70600?

Yes. Cost is the big one. Also harder to fabricate. Also harder to get (lead times can be long). Titanium also has a galvanic corrosion risk when coupled with other metals. C70600 is more forgiving in mixed-metal systems. And titanium does not release copper ions, so it does not prevent biofouling (but biofouling does not harm titanium).

Q8： Does C70600 or titanium better resist biofouling?

C70600 is better because it releases copper ions that kill barnacles and mussels. Titanium does not release anything. Marine growth attaches to titanium just like it attaches to plastic. For heat exchangers that are hard to clean, C70600 has an advantage. For titanium, you need to clean more often or use a coating.

Q9： Can titanium be used at higher temperatures than C70600 in seawater?

Yes, titanium works fine at 100-150°C. C70600 corrodes fast above 60°C. If your heat exchanger sees warm seawater (tropical locations, recirculating cooling, some process applications), titanium is the better choice. C70600 will not last.

Q10： Which material is stronger?

Titanium is stronger. Tensile strength of Grade 2 titanium is about 345-450 MPa. C70600 is 310 MPa. Yield strength is also higher. But strength is rarely the limiting factor for heat exchanger tubes. Corrosion resistance and cost matter more.

Q11： Does titanium work in polluted seawater where C70600 fails?

Yes. Sulfides do not affect titanium. C70600 fails quickly in sulfides. If your seawater comes from a polluted harbor, estuary, or industrial outfall, C70600 is risky. Titanium is safe. Test your water chemistry before deciding.

Q12： Which material do most new seawater heat exchangers use?

For normal conditions, C70600 is still the most common choice. Titanium is used for tough conditions or premium long‑life designs. For shipboard heat exchangers, C70600 dominates. For coastal power plants, C70600 is standard. Titanium is specified only when needed.

First, chemistry. We put a sample in our spectrometer (ASTM E1473). Nickel has to be between 9% and 11%. Iron between 1% and 1.8%. If it's off, the whole melt is rejected. No argument.

Then mechanical. One tube per heat gets pulled until it breaks (ASTM E8). Must hit 310 MPa. We also flatten a ring. Squeeze it to three times the wall. If it cracks, reject. Flare a sample with a 30° cone. If it splits, reject.

Then eddy current. This is 100% of tubes. A probe goes through every single tube (ASTM E243). Any signal above the line, the tube is out. No patching. No "good enough".

You get a Mill Test Report with every order. Heat number on every tube. If you want SGS or BV to watch, we can set that up.

Each tube gets plastic caps on both ends. Keeps dirt and water out. Between layers, we put VCI paper. Stops rust from condensation during the long boat ride.

Each bundle gets shrink wrapped. That seals out moisture. Then steel straps, four to six per bundle. For small tubes or cut lengths, we use wooden cases. For standard 6m tubes, steel straps on a wooden pallet.

The label is waterproof. It shows grade (C70600 / 90/10), size (OD x BWG), heat number, quantity, and length.

Before the container closes, we take photos and tape the packing list inside the door. We send you the photos.

Three melting furnaces, 5 tons each. Copper, nickel, iron go in. Liquid alloy comes out.

Two casting lines pour that liquid into solid billet. 80mm to 220mm across.

Two extrusion presses (2500T and 3500T) punch a hole through the billet. Now it's a hollow shell.

Four pilger mills roll the shell down. Smaller diameter, smoother surface.

Eight drawing benches pull the tube through dies. This gets the exact OD and wall thickness you asked for.

Four annealing furnaces heat the tube to 600°C. That softens it so you can bend it and roll it into tube sheets.

Three straightening and cutting lines make the tube straight and cut it to your length.

Two eddy current machines check every tube before packing.

Discuss Your Project Requirements