The problem is that ASTM A36 does not come in pipe/tube form. I spoke with a few pipe suppliers to verify this. Most of the places online listing ASTM A36 pipe for sale are in India or china and after some digging turn out to be ASTM A53, API 5L pipe etc...
ASTM A36/A36M-19 states, "This specification covers carbon steel shapes, plates, and bars of structural quality for use in riveted, bolted, or welded construction of bridges and buildings, and for general structural purposes."
as you can see, no pipe or tube listed.
ASTM A36/A36M-19 also states, "When components of a steel structure are identified with this ASTM designation but the product form is not listed in the scope of this specification, the material shall conform to one of the standards listed in Table 1 unless otherwise specified by the purchaser."
This is where I got ASTM 500Gr.B from. See table 1 below.
Table 1
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Steel rivets A502, Grade 1
Bolts A307, Grade A or F568M, Class 4.6
High-strength bolts F3125/F3125M, Grade A325 or A325M
Steel nuts A563 or A563M
Cast steel A27/A27M, Grade 65–35 [450–240]
Forgings (carbon steel) A668/A668M, Class D
Hot-rolled sheets and strip A1011/A1011M, SS Grade 36 [250] Type 1 or Type 2 or A1018/A1018M, SS Grade 36 [250] Type 1 or Type 2
Cold-formed tubing A500, Grade B
Hot-formed tubing A501
Anchor bolts F1554, Grade 36
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