# How can I calculate the yield strength of steel tube?

There's a lot of information -- and even some debates -- on which has a stronger yield strength between square and round steel tube. The majority points to square when the dimensions are equal at the same gage (1"x1" square vs. 1" diameter round).

However, what about square vs. rectangle? Assuming same gage, is the yield strength of a 1" x 1 1/2" that much stronger than 1" x 1"? What about 1/2" x 1 1/2" vs. 1" x 1"? Do you have to be a physicist to be able to make this calculation on your own or is there a layman's method of determining this?

• I'm not a rocket surgeon, but...I believe the yield strength of a HORIZONTAL tube would be in the planes perpendicular to the ground. So as long as the long side of the rectangle is perpendicular to the ground, it will be stronger than a square one with shorter sides. (it's basically acting as a joist at this point, and the thicker the joist, the stiffer it will be). For a vertical support, I believe the maximum strength comes from the narrowest dimension (that being the weakest 'link')
– DA01
May 2, 2013 at 17:05
• The yield strength of structural steel is always 250 MPa regardless of shape. May 2, 2013 at 18:31