Tubular Steel Products: Mechanical Tubing vs. Structural Tubing

Mechanical Tubing vs. Structural Tubing

You can generally break down tubular steel products into two factions: mechanical and structural. Knowing the differences in mechanical tubing vs. structural tubing can help you better describe your needs to your manufacturer.

What makes your steel tubing mechanical or structural? Here's how manufacturers classify these two  types of tubing based on their end use.

Mechanical Tubing Vs. Structural Tubing

  Properties Applications
Mechanical tube Tight tolerances, precise specs Machinery and tools -- automotive, agriculture, etc.
Structural tube Strength and durability High-stress uses -- buildings, infrastructure, etc.

The difference between the two types of tubing shows in two main characteristics: their properties and their applications.

Mechanical and structural tube have a lot in common at first glance. Both types can be square shaped, round, or rectangular (however, mechanical tubing is often found in a variety of other shapes). Both can be made of ...

... as long as the material is strong enough to stand up to stressful structural use. (Stainless steel tubular products are among the great opt

Both types can be fabricated after production (though this will depend on the material and galvanization). Fabrication includes:

  • Cutting
  • Punching
  • Stamping
  • Welding
  • Other secondary services

Both are measured by inside dimensions (I.D.), outside dimensions (O.D.), and gauge (wall thickness).

Both can also be used in structures -- though mechanical tubing is only used in very light structural applications.


Mechanical Tubing is produced to strict tolerances and specifications (ASTM A513). Mechanical tubing requires much more precision than the structural stuff -- its chemistry, measurements, and requirements are strictly laid out and adhered to, since its applications tend to be more sensitive than holding up a building.

Seamless mechanical tubing can help avoid weak points in the component. Seamless tubes aren't subjected to welding and therefore aren't extra-prone to corrosion and such.

Structural Tubing has looser requirements (ASTM A500). As its end uses are purely structural, this type of tubing needs to be strong and durable above all else. Tight tolerances and appearance are less important. Structural tube is often called HSS, or hollow structural sections.


Obviously, the main difference between mechanical and structural tubular steel products is how they're used.

Mechanical tubing is used in a variety of applications that require specific measurements, as well as in very low-stress structural applications. Mechanical tubing is most often used in machinery and tools for all industries, from automotive to agriculture.

Other common uses for mechanical tubing include:

  • Solar Panel Supports
  • Conveyor Belt Components
  • Industrial Machinery
  • Playground Equipment
  • Greenhouse Structures
  • Restaurant, Kitchen, & Food Service Parts
  • Hospital Beds & Medical Equipment
  • Canopies and Other Recreational Stands
  • Home & Garden Tools

Structural tubing is used in more high-stress, long-term, corrosive structural applications. Obviously  such as:

  • Infrastructure (Roads, Bridges, Buildings)
  • Construction & Construction Equipment
  • Sign Supports
  • Drilling & Underwater Platforms
  • Roll Cages

Mechanical or Structural Tubular Steel Products?

How do you know if your steel tube products are mechanical or structural? How do you know which one you need? Basically, if your tubing isn't holding up a building or taking a beating from its usage, you've probably got mechanical tubing on your hands. If it is holding up a building or weathering a harsh environment, it's most likely structural tube.

Identifying mechanical vs. structural tubing doesn't ultimately matter for your bottom line. However, it can help you be more precise when describing your needs to your manufacturer.

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(Editor's note: This article was originally published in March 2016 and was recently updated.)

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