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Which Is Better: Stainless Steel vs Aluminum Tubing?

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bending stainless steel tubing

Both aluminum tubing and stainless steel tubing have their strengths and weaknesses. Why might you choose one type of tubing over the other?

Both aluminum and stainless steel are produced on a spectrum of alloys. All of these alloys have different chemical and physical properties.

Generally, stainless steel alloys are categorized into austenitic, ferritic, and martensitic steels. Aluminum is categorized by heat treatability and temper.

So, for your project, which is better: stainless steel or aluminum?

Stainless Steel vs Aluminum Tubing

CONDUCTIVITY

Aluminum is a strong conductor, which can be good or bad depending on your application. The 1000-series of aluminum alloys are the best conductors. This series is used to make products like bus conductors.

If you’re looking for lower conductivity, steel is the better option for you.

WEIGHT

By volume, steel is three times heavier than aluminum. Again, this can be good or bad depending on your needs. Heavier metals tend to be stronger by default.

If your application is consumer or lightweight (such as kitchen supplies, medical tools, or aerospace) aluminum will provide more ease of use. If your application is structural or otherwise weight-indifferent, steel will do the job at a lower cost.

STRENGTH

As we mentioned above, stainless steel’s increased weight comes with increased strength. Steel can withstand higher shock, impact, stress, and pressure than aluminum. It’s less likely to bend or give under pressure.

Stainless steel’s strength is further increased by its alloy – high-carbon steels are harder and sturdier than low-carbon steels. Increased levels of chromium and molybdenum also contribute to overall strength.

DURABILITY

The battle of “aluminum vs. stainless steel: corrosion edition” is not even a close one.

Not only is stainless steel stronger than aluminum, it’s also more durable. It’s less likely to scratch, and it holds up in highly corrosive environments. Higher chromium and molybdenum percentages also contribute to steel’s incredible durability.

Aluminum is simply not as durable as stainless steel. It corrodes much faster (even with finishing) and can’t stand up to high-stress environments or applications. Oxidation and corrosion are bummers for looks, but they also can cause dangerous structural deficiencies.

SECONDARY OPERATIONS

In general, steel has higher weldability than aluminum. It’s easier to weld, and the final welds are more consistent. Steel can be welded with common tools, and doesn’t require a lot of experience.

Aluminum is more finicky to weld and requires more experience.

Stainless steel is also easier to heat treat. Some aluminum alloys are heat treatable, but you should make sure you have the right alloys before requesting them.

COST

A pound of aluminum is much more expensive than a pound of steel.

This cost isn’t as straightforward as you might think. Because aluminum is lighter than steel, you’re also getting more material per pound. That means you can produce more units per pound of aluminum vs. per pound of steel.

Per unit produced, the costs can balance out (but don’t be surprised if aluminum is ultimately more expensive due to raw material costs!). You’ll also need to consider the type of alloy in your final cost analysis.

Which Is Better: Stainless Steel or Aluminum Tubing?

Both aluminum tubing and stainless steel tubing have their strengths and weaknesses. Why might you choose one type of tubing over the other?

Both aluminum and stainless steel are produced on a spectrum of alloys. All of these alloys have different chemical and physical properties.

Generally, stainless steel alloys are categorized into austenitic, ferritic, and martensitic steels. Aluminum is categorized by heat treatability and temper.

So, for your project, which is better: stainless steel or aluminum?

10 Differences Between Aluminum and Stainless Steel

  • Strength to weight ratio. Aluminum is typically not as strong as steel, but it is also almost one-third of the weight. This is the main reason why aircraft are made from Aluminum.
  • Corrosion. Stainless steel is made up of iron, chromium, nickel, manganese, and copper. The chromium is added as an agent to provide corrosion resistance. Also, because it is non-porous the resistance to corrosion is increased. Aluminum has a high oxidation and corrosion resistance mainly due to its passivation layer. When aluminum is oxidized, its surface will turn white and will sometimes pit. In some extreme acidic or base environments, Aluminum may corrode rapidly with catastrophic results.
  • Thermal Conductivity. Aluminum has a much better thermal conductivity (conductor of heat) than stainless steel. One of the main reasons it is used for car radiators and air conditioning units.
  • Cost. Aluminum is typically cheaper than stainless steel.
  • Workability. Aluminum is fairly soft and easier to cut and form. Due to its resistance to wear and abrasion, Stainless can be difficult to work with. Stainless steels are harder and are especially harder to form than aluminum.
  • Welding. Stainless is relatively easy to weld, while Aluminum can be difficult.
  • Thermal properties. Stainless can be used at much higher temperatures than Aluminum which can become very soft above about 400 degrees.
  • Electrical Conductivity. Stainless steel is a really poor conductor compared to most metals. Aluminum is a very good conductor of electricity. Due to its high conductance, light weight, and corrosion resistance, high-voltage overhead power lines are generally made of aluminum.
  • Strength. Stainless steel is stronger than Aluminum (provided weight is not a consideration).
  • Effect on Foods. Stainless steel is less reactive with foods. Aluminum can react to foods that may affect color and flavor.

FAQs

How hard is it to bend stainless steel tubes?

Steel tube bending can be very difficult due to the hardness of the material. However, choosing the right fabricator with proper knowledge of processes and tooling can help make the process more seamless.

Is mandrel tube bending better than roll bending?

The method you choose depends on your bending requirements. Mandrel bending is preferred for bending operations with tighter radii to prevent flattening, wrinkles, and kinks. On the other hand, roll bending is ideal for thinner tubes with a large bend radius.

What are the applications of stainless steel tubing?

Many industries use stainless steel tubes for various applications. They are used in home appliances, automotive and aerospace parts, electronic devices, plumbing systems, medical devices, and many more.

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