As I talk to my colleagues around the country, I’m always asked about what makes an ASTM A1085 or A500 Grade C HSS round better than the ASTM A53 pipe the local fabricator is offering. Since A1085 and A500 Grade C are both structural specifications, round HSS products are produced to be used in structural applications and general construction use. An A53 pipe size tube on the other hand is produced to allow the proper flow of oil, water or gas and is not intended to be used in structural applications. Let’s break down the top five reasons to specify A1085 or A500 Grade C round HSS on your next project instead of A53 Pipe.

1. Yield Strength: The minimum yield strength for an A1085 round is 50 KSI (46 ksi for A500 Grade C). Therefore, A1085 or A500 Grade C HSS rounds have greater strength to weight ratios than A53 round pipes which have a min yield of 35 ksi. So with HSS rounds, you need less steel by weight to do the same job and saves on material costs.
2. Tighter Tolerances: Tighter tolerances for A1085 and A500 Grade C allow the HSS rounds to have a higher degree of quality and less variability. As an example, A1085 and A500 Grade C both have a straightness tolerance: 0.125 times the number of feet in the tube divided by 5 (or 1” for a 40’ section); A53 does not have a straightness tolerance which means the material you receive could be bowed for your application. Another example would be wall thickness tolerances – A53 has a minimum wall thickness of minus 12.5%; A500 has a wall thickness tolerance of plus/minus 10% and A1085 has minus 5%/plus 10%.
3. Coating: A53 products are lacquer coated to reduce corrosion of the steel from the water or gas that will be running through it. In structural applications, this lacquer coating is unnecessary and makes it harder to fabricate, weld or paint. A1085 and A500 Grade C HSS rounds come uncoated, ready to be painted and fabricated as soon as they are delivered.
4. More sizes to choose from: A53 pipe size tubes are only available in nominal pipe size specifications (NPS) such as 6sch40 and two lengths: 21’ or 42’. HSS rounds produced to the A1085 or A500 Grade C specifications not only come in traditional NPS sizes, but also other rounds shapes (5” round x .250” wall). In addition to more sizes, A1085 and A500 Grade C HSS can be bought to custom lengths (Atlas Tube manufactures custom lengths up to 135’). This gives you more flexibility and creativity in your designs instead of relying on standard sizes and lengths.
5. Additional Testing Not Required: Since A53 is used for pressure sensitive applications such as the running of water and gas, it has to go through additional testing processes (i.e. hydro-static testing) that often adds extra costs and time to the manufacture of the product. An A1085 or A500 Grade C HSS does not need to be pressure tested since it is designed to be used in structural applications so no additional testing required.

As we just outlined there are multiple reason for you to specify ASTM A1085 or A500 Grade C on your next structural project you design. If you need to know the availability of these HSS products and others, download our availability chart today! Please send me any additional questions you may have on the differences between A1085 and A500 Grade C HSS vs A53 Pipe, or anything else HSS related: bradlee.fletcher@atlastube.com