I'm looking to replace a 6x6x12 pressure treated post with 4x4 steel tubing. I was looking at a steel handbook and according to the "design strength in axial compression," a HSS4X4X1/4 for an "effective length" of 12ft is 72 Kips (72,000 lbs). Of course you still need to consider bracing, buckling, and other engineering aspects Im not expert in. Still, am I reading this correct? By chance can purchase this HSS cheap and for that kind of strength I'd go with it instead of the PT wood. Thanks and forgive me if I'm posting in the wrong section.