A500 GRB Welded Carbon Steel Tubing

A500 GRB carbon steel welded tube is U.S. standard cold formed welded pipe that is resistance welded as a product, usually without the removal of internal fretting.

It is a structural grade for frames and supports - not a pressure-pipe standard - so the three decisions that actually change your order are shape, outside diameter × wall thickness, and whether you need documentation or coating.

ASTM A500 Grade B is the workhorse grade of cold-formed welded carbon steel structural tubing: electric-resistance welded from strip, then cold-sized and straightened to tight tolerances without heat treatment. 

A500 GRB steel tubing is tested for product analysis using two tubes taken from each lot of 500 tubes or portion thereof, or two pieces of flat rolled stock taken from the corresponding number of flat rolled stock in each lot.

GNEE supplies A500 Gr.B in round, square, and rectangular forms with outside diameters from 0.5 in to 20 in (13–508 mm), wall thicknesses 0.035–1.00 in (0.89–25.4 mm), lengths to 12 m, and black, oiled, or hot-dip galvanized finish, with EN 10204 3.1 mill test certificates and third-party inspection available. Send your OD × wall, shape, and quantity for a quoted lead time.

A500 GRB ERW Structural Steel Pipe Specification

Chemical Composition

The ASTM A500 Grade B chemical composition below is the ladle-analysis (heat) envelope from ASTM A500 Table 1; product-analysis limits are slightly wider, as shown in the second column.

Each element controls a risk: carbon and manganese set strength and weldability, while phosphorus and sulfur are capped for ductility and toughness. For every 0.01% reduction in carbon below the maximum, manganese may rise 0.06% (to 1.50% heat / 1.60% product).

Mechanical Properties

The ASTM A500 Grade B mechanical properties are split by section shape - round and shaped sections carry different minimum yield values, which is the point most often misquoted.

The round-vs-shaped split is the most common misquote in the trade: many catalogs print "46 ksi" for rounds, but 46 ksi (315 MPa) is the shaped-section minimum - rounds are 42 ksi (290 MPa). Specifying the wrong value overstates a round member's capacity.

Grade and Standard Comparison

The selection rule is by load and code, not by habit: pick Grade B for general frames, step up to Grade C only when the section area would otherwise grow, and never cross A500 with A53/A106 for pressure.

Dimensional Tolerances and Surface Finish

Surface finish is a supply choice, not a grade property: black (mill scale), oiled for transit protection, painted, or hot-dip galvanized to ASTM A123 / ISO 1461 for 20–40 year outdoor service. Galvanizing adds no strength but extends life in corrosive environments.

Quality Control and Inspection

Chemical analysis - per heat, verified against A500 Table 1 limits.

Tensile and yield testing - per lot, confirming 400 MPa tensile and the correct 290/315 MPa yield by shape.

Flattening / bend test - per lot, confirming seam integrity for the welded route.

Dimensional inspection - OD, wall, length, and straightness checked 100% against the ordered tolerances.

Documentation - EN 10204 3.1 mill test certificate with furnace traceability; SGS/BV witness available on request.

Why Source ASTM A500 Grade B from GNEE

Integrated mill and export - forming, welding, sizing, and inspection under one roof with furnace-number traceability.

Full documentation - EN 10204 3.1 MTC and SGS/BV third-party inspection on request.

Finish flexibility - black, oiled, painted, or hot-dip galvanized in a single supply chain.

Technical response - engineers confirm grade, shape, and tolerance against your drawing and return a quotation with lead time, typically within 24 hours.

Test and inspection

 

 

 

 

Packaging and shipping

 

Send your shape, outside diameter × wall thickness, length, surface treatment, and quantity - our technical team will confirm the specification against ASTM A500 / A500M-23 and return a quotation with lead time, typically within 24 hours.

Request an ASTM A500 Grade B Quote

FAQ

What is the yield strength of ASTM A500 Grade B?

ASTM A500 Grade B has a minimum yield strength of 42,000 psi (290 MPa) for round tubing and 46,000 psi (315 MPa) for square and rectangular (shaped) hollow sections; tensile strength is 58,000 psi (400 MPa) for both. Many suppliers quote 46 ksi for rounds by mistake - the 46 ksi value applies only to shaped sections per ASTM A500 Table 2.

Is ASTM A500 Grade B the same as A53?

No. ASTM A500 is a structural tubing standard for load-bearing frames; ASTM A53 is a pipe standard for pressure and mechanical service. A500 Grade B has higher yield (42–46 ksi vs A53 Grade B 35 ksi) and tighter dimensional tolerances, but A500 is never mill-hydrotested. Do not substitute A500 for A53 in any fluid or gas line - it is not a pressure piping standard.

What is ASTM A500 Grade B equivalent to in other standards?

The closest grades are EN 10219 S275J0H/S275J2H (yield 275 MPa) in Europe, GB/T 6728 Q235B/Q275 in China, and JIS G 3466 STKR400/STKR490 in Japan. A500 Grade C (50 ksi) maps to S355. These are approximate matches only - confirm with the governing design code before substitution; A500 itself sets no impact-toughness requirement that EN 10219 does.

What are the dimensional tolerances for A500 Grade B pipe?

For round tubing, outside-diameter tolerance is ±0.5% of specified OD up to 1.900 in and ±0.75% at 2.000 in and larger; wall thickness shall not be more than 10% under the specified wall (a one-sided under-tolerance per ASTM A500). Length tolerance is +1/2 in / −1/4 in for lengths up to 22 ft. Some mills hold a tighter bilateral ±10% wall tolerance by agreement.

Is A500 Grade B weldable, and what preheat is needed?

Yes. With maximum carbon 0.26% and manganese 1.35%, the IIW carbon equivalent is about 0.48, so normal-thickness sections weld without preheat using conventional processes. For heavy walls, low-temperature service, or high restraint, follow AWS D1.1 preheat guidance. The mill test certificate does not print CEV automatically - request it on the order.

What is the maximum size of A500 Grade B tubing?

Typical supply is round outside diameters from 0.5 in to 20 in (13–508 mm) and wall thicknesses from 0.035 in to 1.00 in (0.89–25.4 mm); square and rectangular sections run to roughly 12 in (305 mm) per side for shapes. ASTM A500 lists dimensions by agreement, so larger sizes are available on request - confirm the mill's certified range before specifying.

Can A500 Grade B be used for pressure or fluid service?

No. ASTM A500 is a structural specification; it does not require and the mill does not perform a hydrostatic test. It is intended for welded, riveted, or bolted structures - columns, beams, trusses, equipment supports. For steam, water, gas, or air conveyance use ASTM A53 or ASTM A106, which are pressure-pipe standards with mandatory hydrotesting.

How do I specify an A500 Grade B order?

State: (1) standard and grade - ASTM A500 Grade B; (2) shape - round, square, or rectangular; (3) outside diameter or side dimensions and wall thickness; (4) length and end condition; (5) surface treatment (black, oiled, galvanized); (6) any copper-bearing requirement; (7) stress-relief option if needed; (8) documentation - EN 10204 3.1 MTC, third-party inspection (SGS/BV); (9) quantity and destination port. Send these to GNEE for a quoted lead time.

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