When they specify the grade of pipe to bend tubing, most buyers don’t even ask the question: they assume that the company they are buying from is the expert and would know which is best.
The end use is important. To order correctly, you should know the general use of your pipe:
Architectural (fabric tension systems, canopies) — A500 or A252*
Process pipe (gas, oil, water runs thru it so it is pressure tested / hydrostatic test)— API X42 or A53 or A106 Seamless
Structural (sign poles, caissons) A500 or A252*
*Caution: when specifying A252 pipe! We recently had 24 inch pipe specified as A500, a structural grade. But since HSS producers like Atlas do not produce any pipe larger than 20 inch diameter**, we offered A252 grade.
A252 grade can come as an ERW pipe or as rolled and welded pipe with visible circumferential weld seams every five feet and longitudinal welds not lined up from section to section—not very pretty for an architectural element.
**Look at the AISC steel finder tool— it confirms that 20 inch is the largest size that A500 mills make.
