Seamless steel tube has many names but this product has one common denominator – it’s hollow. In fact, this is often referred to by seamless tube manufacturer, fabricators and engineers as “Hollow Structural Sections” or “HSS”. Moreover, tube can be used in endless applications – from the handrails used in a stadium, to supporting long-span warehouses. In fact, tubing is such a multipurpose product, it can be found in uncountable industries. These include:
- Nonresidential construction
- Agriculture
- Infrastructure
- OEMs
- Construction
- Transportation
When would you use steel tube?
As we have mentioned, steel tube is a versatile structural steel product ideal for many applications. In general, you will select a steel tube when you need one of the following characteristics:
- A weight to high strength ratio that lessens the steel amount you need
- Your design should be exposed architecturally with smooth sides. Get steel tube from reputed seamless tube manufacturer as an architect’s first choice for structural steel.
- Less surface area for your coatings – tube has approx. 2/3 less surface area which needs less painting
- Closed section – designed to counterattack torsional loads as well as dust collection in clean facilities
What are common specifications for steel tube?
Upon ordering a steel tube, indeed it is crucial to take note of the final application it will be going into. Take example, if it is going for a commercial application such as a lawn mower handle, you may consider an ASTM A513 tube. But, if your requirement is for a load bearing application, ASTM A500 will be your option. In fact, ASTM A500 and ASTM 513 are the two most common steel tube specifications currently in the market.
What is ASTM A500 tubing?
ASTM A500 specification is applied on structural tubing in three common shapes: rectangles, squares, or rounds. In fact, ASTM A500 tubes are for the applications where load-bearing quality are needed. Moreover, upon ordering ASTM A500 tubing from your service center, you should get an MTR, or Material Test Report. It should show the steel coil chemical composition that was used for tube manufacturing, but also the Yield, Tensile and Elongation properties.
Pipe vs Tube – ASTM A500 Grade and Specifications
The most common ASTM grade is Grade C in the marketplace today. Additionally, another commonly specified grade is ASTM A500 Grade B. One thing to denote with both ASTM A500 and ASTM A513 tubes is the ID or inside diameter is not measured and therefore, for the specifications are not guaranteed. Moreover, another interesting aspect of structural tube is that the shapes and rounds are different.
Chemical Requirements
| Element | Grade B | Grade C | ||
| Heat Analysis | Product Analysis | Heat Analysis | Product Analysis | |
| Carbon, max | 0.26 | 0.30 | 0.23 | 0.27 |
| Manganese, max | 1.35 | 1.40 | 1.35 | 1.40 |
| Phosphorus, max | 0.035 | 0.045 | 0.035 | 0.045 |
| Sulfur, max | 0.035 | 0.045 | 0.035 | 0.045 |
| Copper, min (when specified on PO) | 0.20 | 0.18 | 0.20 | 0.18 |
Tensile Requirements – Round Structural Tubing
| Grade B | Grade C | |
| Tensile strength, min psi | 58,000 | 62,000 |
| Yield Strength, min psi | 42,000 | 46,000 |
| Elongation in 2” min, % | 23 | 21 |
Tensile Requirements – Shaped Structural Tubing
| Grade B | Grade C | |
| Tensile strength, min psi | 58,000 | 62,000 |
| Yield Strength, min psi | 46,000 | 50,000 |
| Elongation in 2” min, % | 23 | 21 |
Pipe vs Tube – How do you typically order steel tube?
Upon ordering a steel tube from the house of a reputed seamless tube manufacturer, you should list the size dimensions you need, the thickness or gauge, and the length. Additionally, you must provide the specification of the tube since some sizes can be either ASTM A500 or ASTM A513. Moreover, sometime you order with the decimal or the gauge – either way is correct. Some of the more common ways to order include:
1 x 1 x .120 x 240”, A513
1 x 1 x 11ga x 20’, A513
2”x2” x .250” x 20’, A500
.5x.5 -16ga P&O x 288”, A513
10×10 x .625” x 48’, A500
Since tube also comes in round shapes, it is often referred to as “pipe size tube”. Typically, a round tube is ordered to the standard NPS sizes and lengths – as an example, 1.25sch40 x 21’. In fact, it can also be ordered by its true size: 1.66” x .140” x 252”, A500. In addition, round tube comes in a wider range of sizes than a traditional “pipe”. Common tube rounds include:
5 x .188 x 20’, A500
3” x .250” x 24’, A500
5” x ¼ wall x 20’, A500
How do I know when I need “tube” instead of a “pipe”?
Stay tuned to our next blog in the “Pipe vs Tube” series for the answer to this often-asked question!
