hi canadaboy
fyi, 44w is considered a "structural quality steel" which conforms to CSA G40.21-87 (use for cranes, steel frame structures eg aircraft hangars, warehouses, highrises etc.) see
web page
my opinion is that it would be fine for what you are wanting if designed correctly. my expertise is not in structural steel design so it would be inappropriate for me to design it, however, given that you get the stuff for free and if it were my stand i was building i would do it but not just a simple post and beam design. consider running several rails on the long span, and possibly torsion members (ie 45 degree bars from top to sides).
i could provide more info if you have the strenght properties of the tube - the supplier can give you this if your company doesn't already have it. an ex. of what you need is below (from A-36 low-carbon steel).
fwiw, powder coating is really cheap and provides a superior long lasting finish if done well.
shane
Mechanical Properties Metric English Comments
Tensile Strength, Ultimate 400 MPa 58000 psi
Tensile Strength, Yield 315 MPa 45700 psi
Elongation @ break 23 % 23 %
Bulk Modulus 140 GPa 20300 ksi Typical for steel
Shear Modulus 80 GPa 11600 ksi Typical for steel