Hollow steel bars vs metal tube bars: Which is better?

Written by Nigel Simpkins

If you’re in an industry that requires the use of steel foundational equipment, it can be extremely helpful to know what a hollow steel bar is.

Hollow steel bars can be more cost effective than the traditional metal bar stock because it weighs less than the metal bar, yet the hollow steel bar can still offer as much strength as it’s metal bar counterpart.

Continue reading to learn more about the differences between metal tube bars and hollow steel bars below.

The 3 Main Differences Between Tube And Hollow Bars

There are key three differences that distinguish a tube from a hollow bar:

  • Manufacturing process
  • Quality
  • Materials

Manufacturing Process

For tube and hollow steel bars to take on their different makeups, they have to go through a different manufacturing process. A tube bar is created through slit coils of a base metal being run through a tube mill. This allows the tube to take on a variety of different shapes, such as square, round, or rectangular. When the correct shape is achieved, the tube undergoes a welding process through the use of an electric resistance welding tool.

With a hollow steel bar, unlike with a tube, there is no welding that’s used. Instead two different methods can be used to create a hollow steel bar. The first process is called drilling, and the second is called centrifugal casting. The drilling process creates very accurate part dimensions and the centrifugal casting creates a hollow steel bar that is very dense and uniform.


Typically, hollow steel bars are only made out of two different kinds of material, stainless steel and bronze. Using these two materials allow the steel bars to have a very tight dimensional tolerance.

However, in the case of the tube bars, it can be much more difficult for tight dimensional tolerances to be reached. This is largely due to the welding process. If a manufacturer is not careful while creating the tube bar, it can create a very low quality of product.

In this way, the hollow steel bar can sometimes make for a higher quality product since there is no additional welding processes that are used, whereas the welding process in the tube bar can create different kinds of crystalline structures near the weld zone. Ultimately, this affects the desired mechanical properties that are in the tubing.


With the tube bar, a lot of different kinds of materials can be used to create the welded tubing. For welded tubing, you typically want to use a material that conduct electricity. With the hollow steel bar, you’ll want to use harder materials that are stronger. If the material is too strong though you may want to use a piercing method to create the hollow steel bar.

These are some of the main differences that exist between metal tubes and hollow steel bars. Ultimately which one you decide to use has to do with the bar’s application as neither a hollow steel bar or a metal tube bar is cheaper or better than the other one.