Project Description
Structural Tubing
Structural tubing per ASTM A500 is tubing produced and used for structural applications. Standard strength requirements of the tube help dictate applications for which certain tubing is most appropriate. Structural tube is often referred to as hollow structural sections or HSS. Structural Tubing, especially rectangular sections, are commonly used in welded steel frames where members experience loading in multiple directions. Square and circular HSS are very efficient shapes for this multiple-axis loading as they have uniform geometry along two or more cross-sectional axes, and thus uniform strength characteristics. This makes them good choices for columns. They also have excellent resistance to torsion. The flat square surfaces of HSS structural tubing can ease construction, and they are sometimes preferred for architectural aesthetics in exposed structures. HSS structural tubing is most commonly produced to ASTM A500 grade B standards, but can also be available in ASTM A1085 as well. Structural products are ordered to a specific outside dimension (OD) and gauge or wall thickness.
Stocked Size Range And Shapes
- Square: 0.500″ to 16.000″ with 0.065″ to 0.625″ Wall Thickness
- Rectangle: 1.000″ x 0.500″ to 20.000″ x 12.000″ with 0.065″ to 0.625″ Wall Thickness
- Round: 0.750″ to 20.000″ O.D. with 0.065″ to 0.625″ Wall Thickness
Manufacturing Process
ASTM A500 structural tubing is welded tubing made from flat-rolled steel, formed through a roller system and welded using electric-resistance welding. Longitudinal butt joints of welded tubing shall be welded across its thickness in such a manner as to assure the structural design strength of the tubing section. Welded structural steel tubing is normally furnished without the removal of inside flash.
Benefits Of Structural Tubing
- Strength
- Appearance
- Uniformity
- Ease Of Fabrication
- Cost Effectiveness
- Resistance
Applications By Industry
- Construction & Heavy Equipment
- Agriculture
- Infrastructure
- Fluid Handling
- Machinery
- General Fabrication And Machining
- Automotive & Transportation
Chemical Requirements
| A500 | Grades A, B and D | Grace C | ||
| Heat Analysis | Product Analysis | Heat Analysis | Product Analysis | |
| Carbon, max | 0.26 | 0.3 | 0.23 | 0.27 |
| Manganese, max | … | … | 1.35 | 1.4 |
| Phosphorus, max | 0.035 | 0.045 | 0.035 | 0.045 |
| Sulfur, max | 0.035 | 0.045 | 0.035 | 0.045 |
| Copper, when copper steel is specified, min | 0.2 | 0.18 | 0.2 | 0.18 |
| EN10210/10219 | C Max. | Si Max. | Mn Max. | P Max. | S Max | N Max. |
| S235JRH | 0.17 | – | 1.40 | 0.040 | 0.040 | 0.01 |
| S275J0H | 0.20 | – | 1.50 | 0.035 | 0.035 | 0.01 |
| S275J2H | 0.20 | – | 1.50 | 0.030 | 0.030 | – |
| S355J0H | 0.22 | 0.55 | 1.60 | 0.035 | 0.035 | 0.01 |
| S355J2H | 0.22 | 0.55 | 1.60 | 0.030 | 0.030 | – |
| S355K2H | 0.22 | 0.55 | 1.60 | 0.030 | 0.030 | – |
Mechanical Properties
Tensile strength refers to the amount of stretching stress a material can withstand before breaking or failing. The ultimate tensile strength of A500 carbon steel is calculated by dividing the area of the steel by the stress placed on it, which is expressed in terms of pounds or tons per square inch of material. Tensile strength is an important measure of A500’s ability to perform in an application. A500 carbon steel’s tensile strength is described in the chart below.
| A500 | Grade A | Grade B | Grade C | Grade D |
| Tensile strength, mn, ps (MPa) | 45 000 (310) | 58 000 (400) | 62 00 (427) | 58 000 (400) |
| Yield strength, mn, psi (MPa) | 39 000 (269) | 46 000 (317) | 50 000 (345) | 36 000 (250) |
| Elongation in 2 in. (50.8 mm), min, %A | 25B | 23C | 21D | 23C |
| Mechanical Properties | Elongation (%) | Impact Energy (KV J) | ||||
| Steel Grade | Yield Strength (Mpa) | Tensile Strength (Mpa) | At Test Temperature of °C | |||
| -20 | 0 | 20 | ||||
| S235JRH | 235 | 360-510 | 26 | – | – | 27 |
| S275J0H | 275 | 410-560 | 23 | – | 27 | – |
| S275J2H | 275 | 410-560 | 23 | 27 | – | – |
| S355J0H | 355 | 510-680 | 22 | – | 27 | – |
| S355J2H | 355 | 510-680 | 22 | 27 | – | – |
| S355K2H | 355 | 510-680 | 22 | 40 | – | – |
Permissible Dimensional Variations for Outside Dimensions
Outside diameter measurements for steel tube must be made at positions at least 2″ (50.8mm) from either end of the tubing.
Square structural tubing and rectangular structural tubing must be measured across the flats and include an allowance for convexity or concavity. Specified dimensions shall not exceed the plus/minus allowances shown in the table below.
Outside Dimensional Tolerances for Square & Rectangular Steel tubing
There are multiple considerations that must be accounted for when determining the outside dimensional tolerances for square and rectangular steel tubing. The chart below and the following attributes describes the exact outside dimensional tolerances for A500 carbon steel.
WALL THICKNESS
Minimum wall thickness at any point of measurement shall not be less than 90% of specified nominal wall thickness. Maximum wall thickness, excluding weld seams, shall not be more than 110% of specified nominal wall thickness. Wall thickness of square structural tubing and rectangular structural tubing must be measured at the center of the flat.
STRAIGHTNESS
Permissible variation in straightness for structural tubing is 1/8″ times the total length in feet (or 10.4mm times the number of meters) divided by five.
SIDE SQUARENESS
For square structural tubing and rectangular structural tubing, adjacent sides may deviate from 90° by no more than ±2°.
CORNER RADII
For square structural tubing and rectangular structural tubing, the radius of anyone outside corner may not exceed three times (3x) the specified wall thickness.
TWIST
For square structural tubing and rectangular structural tubing, the tolerances for twist (variation with respect to axial alignment) are shown in the table below.
Twist Tolerances for Square & Rectangular Structural Tubing
Twist is measured by either holding down one end of a square/rectangular tube on a flat surface, with the bottom side of the tube parallel to the surface plate of the two corners at the opposite end of the bottom side of the tube; or, by measuring this difference on the heavier sections by a suitable measuring device. Difference in the height of the corners must not exceed the values in the table above.
Contact Fushun for Steel Structural Tubing Today
Contact us for more information regarding ASTM A500 / EN 10210 / EN10219 steel structural tubing specifications and product options, or request a quote for further pricing details today.