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Angle Iron: Understanding the Uses of Angle Iron Based on Its Structural Integrity Strengths

While people that use angle iron and steel in Houston TX understand that structural iron and steel are stronger than non-structural iron and steel, they generally don't know why nor when using angle iron is appropriate. As a result, many people do not use it for the purposes it was designed to serve.

At Texas Iron and Metal, we believe that when our customers understand the strengths and weaknesses of angle iron, it is much easier for them to determine whether it is suited for a job or if there are other types of iron that would be better suited : rectangular tubing, I-beams and channels, for example.

Greatest Load Bearing Aspects of A-Iron

A-iron is stronger than non-structural steel because the two perpendicular flanges work in conjunction to give angle iron cross-sectional structural integrity, resistance to bending from pressure applied from the top or bottom, left or right.

The two flanges that make up the angle create a compound area. A compound area is the location of the axis of a piece of structural steel that is most resistant to the moment of inertia. The moment of inertia is when a static body begins moving around an axis.

The compound area is the most resistant load bearing area of a piece of structural steel -- the area most resistance to the moment of inertia. In A-iron, the compound area is located in the trough between the two flanges.

But the physics of A-iron are not as important as the end results.

Layman's Explanation of A-Iron's Strengths and Weaknesses

Angle iron is relatively resistant to the moment of inertia when the load is applied the top, bottom or either side. However, when pressure is applied in a manner that rotates the A-iron around the axis of the compound area, it will fail with the application of less pressure than when the pressure is applied around the cross section.

In other words, when A-iron is twisted from one end or the other, that is when its structural integrity is most vulnerable.

Simply, A-iron is hard to bend, but easy to twist.

Implications of A-Iron's Strengths and Weaknesses

Angle iron works extremely well when used conjunctively. By welding pieces together at 90 degree angles and bracing the angles of the welds with short pieces at 45 degree angles, A-iron's susceptibility to twisting is greatly reduced.

That means A-iron is a sound and solid material to use for the framing of:

  • crates and boxes
  • cages
  • load bearing support structures (trusses for small buildings)
  • free-standing, load-bearing frames (kiosks and bed frames)

A-iron is not good to use to span large distances, to support heavy loads as individual units or in any manner that twists the iron such as:

  • fence posts
  • light poles
  • lean-to supports
  • home-made ladders
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