ASTM A500 standard specification covers carbon steel, cold formed welded and seamless structural tube in both round and shaped forms.
The ASTM A500 specification covers cold-formed welded and seamless carbon steel tubing in round, square, rectangular, and “special” shapes for welded, riveted, or bolted construction applications, as well as for general structural purposes.
Round and shaped steel cold formed welded and seamless carbon steel structural pipe.
Standard: ASTM A500 for Cold-Formed Welded and Seamless Carbon Steel Structural Tubing in Rounds and Shapes.
ASTM A500 is a standard specification for cold-formed welded structural tubing produced to round nominal pipe sizes.
Main purpose:
- electricity
- petroleum
- chemical companies
- high temperature
- low temperature resistance
- corrosion-resistant piping systems.
ASTM A500 structural pipe is welded pipe sized 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.
Specifications:
- OD :10.3-820 mm
- wall thickness: 0.8 to 75 mm
- Length: 6m
In addition, based on customer requirements, which can supply other grades and specifications of steel pipe.
Processing: steel shall be in accordance with one or more of the processing: open-hearth, blowing oxygen, or electric furnace steelmaking, casting of different grades of steel in order, steel producers should determine the intermediate material using conventional procedures removed, a clear separation of a Level.
Manufacturing: produced by seamless or welded steel pipe, welded pipe by rolling made by resistance welding.
Structural design strength of the longitudinal direction of the pipe, the docking application tube is a method of determining the through its thickness to weld.
Chemical Component(%)
| Grade | C | M | P | S | Cu |
| Gr.A | 0.26 | 1.35 | 0.035 | 0.035 | 0.20 |
| Gr.B | 0.30 | 1.40 | 0.045 | 0.045 | 0.18 |
| Gr.C | 0.23 | 1.35 | 0.035 | 0.035 | 0.20 |
| Gr.D | 0.27 | 1.40 | 0.045 | 0.045 | 0.18 |
Mechanical Properties Min (MPa)
| Grade | Tensile Strength | Yield Strength | Elongation |
| Gr.A | 310 | 230 | 25 |
| Gr.B | 400 | 290 | 23 |
| Gr.C | 425 | 315 | 21 |
| Gr.D | 400 | 250 | 23 |
Impact test requirements for ASTM A500 Gr.C
Mixture Requirements
According to ASTM rules, all tubing must have the chemical mixtures of carbon, manganese, phosphorus, sulfur and copper present. In addition, the steel produced must be done by open-hearth, basic-oxygen or electric-furnace melting methods. It is not enough to have the correct chemicals mixed in the tubing; materials must also undergo specific welding methods in order to be approved by ASTM A500.
Welding Procedures
In addition to the three aforementioned steel-producing methods, tubing must also be welded using flat-rolled steel. The flat-rolled steel should be formed
into a tube using the electric-resistance welding process. Using the electric-resistance welding process will assist the material in passing the tension and flattening test that evaluates the sturdiness of the piece.
Shape
ASTM rules require that the longitudinal butt joint of the tubing be thickly welded in order to assure the secure structural design of the piece. ASTM will not approve tubing that has a weak joint because such weakness may pose a problem to the entire structure. Thousands of structures built with poor still joints would be in danger of collapsing if the ASTM did not uphold this regulation.
Manufacture
ASTM A500 spec states that welded tubing shall be made from flat-rolled steel 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 typically furnished without the removal of inside flash.
Inspection
Before the manufacturer is given permission to market products, all tubing must be inspected by an ASTM representative. The purpose of the inspection is to assure conformance to structure requirements; tubing that fails to pass inspection must either be corrected or discarded. In addition, the appearance of tubing must be professional and free from defects; it should not, for example. be severely burned or have bumps or blotches of steel in any one place.
Outside dimensions
Outside diameter measurements must be made at positions at least 2” (50.8mm) from either end of the tubing. For round structural tubing with nominal OD of 1.900” (48.26mm) and smaller, the outside diameter may not vary more than ±0.5%, rounded to the nearest 0.005” (0.13mm), of the specified size. For nominal ODs of 2” (50.8mm) and larger, outside diameter may not vary more than ±0.75%, rounded to the nearest 0.005”. 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 Dimension Tolerances For Square and Rectangular Structural Tubing
| Outside Large Flat Dimension, in. (mm) | Large Flat Dimension Tolerance, A plus and minus, in. (mm) |
|---|---|
| 2½ (63.5) or under | 0.020 (0.51) |
| Over 2½ to 3½ (63.5 to 88.9), incl | 0.025 (0.64) |
| Over 3½ to 5½, inc | 0.030 (0.76) |
| Over 5½ (139.7) | 0.01 times large flat dimension |
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.
A500 Grade A, B & C Tubing
Sunny Steel supply square, rectangle, round and special shaped electric resistance welded (ERW) carbon steel tubing to meet ASTM specifications A500 Grade A, Grade B and Grade C that is often used in structural applications. The purpose and strength levels required will determine which grade is required.
Square & Rectangle Tubing
Below are physical properties required to meet the three grades that we produce ASTM A500 square, rectangle and special shaped tubing to. A flattening test is not a standard requirement for non-round tubing produced to A500.
| Grade | Yield (min) | Tensile (min) |
|---|---|---|
| Grade A | 39,000 psi | 45,000 psi |
| Grade B | 46,000 psi | 58,000 psi |
| Grade C | 50,000 psi | 62,000 psi |
Round Tubing
Below are physical properties required to meet the three grades that we produce ASTM A500 round tubing to. A flattening test is also a standard requirement for round tubing produced to the A500 specification.
| Grade | Yield (min) | Tensile (min) |
|---|---|---|
| Grade A | 33,000 psi | 45,000 psi |
| Grade B | 42,000 psi | 58,000 psi |
| Grade C | 46,000 psi | 62,000 psi |
Specification Notes
- According to ASTM A500, the weld seam location for square, rectangle and other special shaped tubing shall not be located within the corner radius unless specified by the customer or manufacturer.
- Under ASTM A500, the corner radius for square and rectangular tubing shall not exceed three times the corner radius.
- As a standard under ASTM A500, electric resistance welded tubing is normally provided without removal of inside flash. If flash control is required, please specify at time of quotation or order placement.
- ASTM A847 is a related structural specification that covers high strength low alloy atmospheric corrosion resistant steel tubing. Please refer to the ASTM A847 page for more information.
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