Round Tube
Welded round tube from 1.900 to 8.000 inches outside diameter, in walls from 14 gauge to .300 inch and lengths to 48 feet, to ASTM A500, A513 or A787.
Named by what it measures.
Every round we make is sized by its outside diameter, from 1.900 to 8.000 inches.
What It Becomes.
Round tube bends evenly in any direction and resists twisting, so it is the choice for rails, handles, posts and anything that turns. The large sizes go where a part has to be both stiff and long.
- Handrail and guardrail
- Fence posts and top rail
- Seat and chair frames
- Fitness equipment
- Implement axles and sleeves
- Mower and cart handles
- Playground and park structures
- Solar piers and tracker torque tubes
- Structural columns
- Bollards and guard posts
- Fence terminal and gate posts
- Sign posts and conveyor rollers
Large Round, 4.500 to 8.000 OD.
Large rounds are made in Erie with our square, rectangular and smaller round tube, so the heavy members of a job ship with the rest of the order.
- Diameters
- 4.500 to 8.000 ODFor torque tubes, columns and terminal posts that need more than a 3-1/2 inch round.
- Walls
- .090 to .300 inFormed from hot rolled or cold rolled coil. Heavy walls carry more load for the diameter and stand up to driving and handling.
- Lengths
- Up to 48 ftLong runs need fewer splices and less welding. Shorter mill lengths and cut lengths are available too.
How Large Rounds Hold Their Size.
What happens on the mill shows up in the tube: a steady outside diameter, a straight length and a clean, square end.
Every Roll Driven on Its Own
Each forming and sizing roll has its own motor, so roll speeds stay matched as rolls wear. Matched rolls form the strip evenly and hold the diameter from the first length to the last.
Weld Trimmed Inside the Line
The weld is made by high-frequency induction and the outside bead is scarfed off right after the weld, while the steel is hot.
Straightened at the Runout
The straightening stands are adjusted from the end of the mill, where the operator can see the finished tube, and the settings are shown on screen.
Cut by an Orbital Saw
A saw that travels with the tube cuts each length while the mill keeps running, leaving a square, clean end with little burr.
Stacked and Strapped Automatically
Lengths are counted into the bundle, stacked and strapped with steel bands by machine, so every bundle of a size comes out the same.
How to Pick a Diameter and Wall.
Start from what the tube has to fit, then from how it is loaded or bent. The diameter usually follows a fitting, a bearing or a grip; the wall follows the load.
Match the Fitting
1.900, 2.375, 2.875 and 3.500 are pipe diameters, so pipe caps, clamps and fence fittings fit them. 2.000 and 2.500 are tube sizes, for parts that slide into a sleeve or a bearing sized in even inches.
Same in Every Direction
Round tube is equally stiff whichever way the load comes, and a closed round section is the most efficient shape against twisting. That is why axles, torque tubes, posts and handles are round.
Wall for the Load
A heavier wall for the diameter bends with less flattening and wrinkling, and a consistent outside size lets a bender die grip every piece the same. For tight bends, A513 is the usual order. For columns and driven posts, the large rounds run to a .300 wall.
Mill Lengths and Bundles.
- Mill Lengths
- 20 to 48 ftStandard bundles are 20, 24 and 40 feet, with clean cold-saw ends.
- Pieces per Bundle
- 61 / 37 / 242.000, 2.500 and 3.500 OD at 20 and 24 feet. Smaller bundles are available to suit your crane or forklift.
- Least Waste
- Check the DropA 6-1/2 ft rail leaves a 6 in drop from 20 ft but 4-1/2 ft from 24 ft. The cut-length calculator checks every standard length.
- One Truck
- Large and SmallLarge and smaller rounds can ship together. The bundle planner gives pieces, layout and weight per bundle and per load.
Questions.
Need a size between those listed, or a wall outside the table? Ask; round sizes follow the mill's forming rolls.
What sizes of round tube do you make?
Round tube from 1.900 to 8.000 inch outside diameter. The smaller rounds are 1.900, 2.000, 2.375, 2.500, 2.875 and 3.500 OD, in walls from .083 (14 gauge) to .188 (3/16 inch). Large rounds run from 4.500 to 8.000 OD in walls from .090 to .300 inch.
What is the largest round tube you make?
8.000 inch outside diameter, in walls up to .300 inch and lengths up to 48 feet.
Is your round tube pipe?
No. Pipe is named by a nominal size and schedule; our round tube is sized by its actual outside diameter. Four of our rounds, 1.900, 2.375, 2.875 and 3.500 OD, match standard pipe diameters and come in Schedule 10 and 40 walls, so pipe fittings fit them. They are A500 structural tube, not A53 pressure pipe. See rounds at pipe diameters.
What lengths are available?
Standard bundles are 20, 24 and 40 feet. We run mill lengths from 20 to 48 feet, and we can cut to your length.
How tight is the outside diameter?
A513 round tube is held to .005 to .009 inch either way up to 3.500 OD, and the tolerance widens with the diameter above that. A500 tolerances are wider. See How to Measure Tube for the tables.
Should I order A500 or A513 round tube?
A500 when the tube carries a load an engineer calculated: Grade C round has a minimum yield of 46,000 psi. A513 when the part is bent, fitted or finished, since it holds the outside diameter closer. A500 vs. A513 compares them.
What fits 1.900 OD tube?
Fittings, caps and clamps made for 1-1/2 inch pipe, since 1.900 is the outside diameter of 1-1/2 inch nominal pipe. The same goes for 2.375 (2 inch), 2.875 (2-1/2 inch) and 3.500 (3 inch).
Which spec is better for bending round tube?
A513 is the usual choice for bent parts, because its closer outside diameter lets a bender die grip every piece the same. A heavier wall for the diameter also bends with less flattening.
How do I work out the weight of round tube?
Pounds per foot is about 10.68 times (OD minus wall) times wall, in inches. For 2.375 x .120 that is 2.890 lb/ft; for 6.625 x .188, 12.92 lb/ft. The tube weight calculator does it for any length and quantity.
Can I order large and small tube on the same truck?
Yes. All of our tube is made in Erie, so large round tube can ship with square, rectangular and smaller round tube on one load.
What do I need to send for a quote?
The size and wall, the spec and finish, the length (mill length, or your cut length and tolerance), the quantity per order or per year, and where it ships. The quote form asks for each one. Give the outside diameter in decimals and the wall as a decimal. For pipe diameters, the nominal size and schedule work too.
Technical Data.
Sizes and weights to 8.000 OD, rounds at pipe diameters, specifications and tolerances.
Sizes and Weights, 1.900 to 3.500 OD.
Pounds per foot for every diameter and wall on our standard list. Pick a number to open it in the size finder.
Outside diameter in inches. A dash means not on the standard list in that wall; ask us.
1.900, 2.375, 2.875 and 3.500 are pipe outside diameters, so these sizes fit pipe fittings and clamps.
Sizes and Weights, 4.500 to 8.000 OD.
Pounds per foot for each diameter and wall on our large round list. Pick a number to open it in the size finder.
Outside diameter in inches. Weights are calculated from the size and wall. We run walls from .090 to .300; ask about walls not shown.
Large rounds are formed from hot rolled or cold rolled coil up to 80,000 psi tensile strength. Diameters between those listed follow the mill's forming rolls; ask us.
Rounds at Pipe Diameters.
Four of our rounds match standard pipe outside diameters, so pipe-size fence fittings, caps and clamps fit them. They are A500 structural tube, not A53 pressure pipe.
| Matches pipe size | ODin | Sch 10 wallin | Sch 10lb/ft | Sch 40 wallin | Sch 40lb/ft |
|---|---|---|---|---|---|
| 1-1/2 in | 1.900 | .109 | 2.085 | .145 | 2.718 |
| 2 in | 2.375 | .109 | 2.638 | .154 | 3.653 |
| 2-1/2 in | 2.875 | .120 | 3.531 | .203 | 5.793 |
| 3 in | 3.500 | .120 | 4.330 | – | – |
3 in Schedule 40 (.216 wall) is not on our standard list; ask us. Other walls at these diameters are in the size table above.
Which Specification to Order.
Every round, large or small, is made to the same specifications. Round tube in A500 is rated a little lower than the same steel in square, because squaring the tube work-hardens the corners.
ASTM A500
Structural round tubing, usually dual-certified to Grades B and C, for columns, posts and frames an engineer has sized.
- Grade B yield
- 42,000 psi min.
- Grade C yield
- 46,000 psi min.
- Tensile
- 58,000 / 62,000 psi
ASTM A513
Mechanical round tubing, as-welded from hot rolled (Type 1a) or pickled and oiled (Type 1b) steel, held to tighter diameter tolerances for parts that are machined, fitted or bent.
- Ordered by
- OD, wall, finish
- Strength
- Set by the steel grade
ASTM A787
Mechanical round tubing made from galvanized steel, for outdoor parts that are not painted.
- Coating
- Zinc, from the coil
- Used for
- Fence, posts, railing
What the Spec Allows.
Unless an order says otherwise, round tube is made to the ASTM tolerances for the spec ordered, and they widen with the diameter. Measure the outside diameter at least 2 inches from a cut end, turning the calipers to find the largest and smallest readings.
A513 Mechanical
- 1.900 and 2.000 OD
- ±.005 in
- 2.375 and 2.500 OD
- ±.006 in
- 2.875 OD
- ±.008 in
- 3.500 OD
- ±.009 in
- 4.500 to 8.000 OD
- Per A513, by diameter
- Straightness
- .030 in in 3 ft
A500 Structural
- Outside diameter
- Per A500, wider than A513
- Wall
- ±10% of nominal
- Straightness
- .025 in times the length in feet
Out of Round
Round tube may be oval by up to 50% more than its OD tolerance, as long as the average of the largest and smallest diameters is in tolerance. Measure both at the same spot and average them.
Tell Us the Size,
Wall and Footage.
One size or a whole program, in mill lengths to 48 feet or cut to your length. The quote form takes about two minutes.