ASTM A500 Grade C Cold-Formed Welded Carbon Steel Structural Square Tubing

Material

ASTM A500 Grade C is a cold-formed, electric-resistance-welded (ERW) carbon steel structural hollow section (HSS) in a square profile, designed for welded, riveted, or bolted construction (e.g., bridges, buildings, and general structural fabrication).

Specifications

• Product form: Square structural tubing (HSS)

• Manufacturing: ERW from flat-rolled steel; welded across thickness. (Inside flash is normally not removed unless specified.)

• Standard size envelope (per ASTM A500): Periphery ≤ 88 in [2235 mm]; specified wall thickness ≤ 0.875 in [22 mm]

• Lengths: Typically produced in random lengths 5 ft [1.5 m] and over, in multiple lengths, and in specific lengths

• Key dimensional tolerances (square/rectangular):

  • Wall thickness: –10% / +10% (center of flats; excluding weld seam for max)

  • Squareness of sides: 90° with ±2° max variation

  • Outside corner radius: ≤ 3 × wall thickness (3t)

  • Straightness: 1/8 in × (total feet ÷ 5)

  • Specific length tolerance: +1/2 in / –1/4 in (≤22 ft); +3/4 in / –1/4 in (>22 ft)

Main Features

• High strength for structural design: Grade C shaped tubing minimum Fy 50 ksi [345 MPa] and Fu 62 ksi [425 MPa]

• Fabrication-friendly: Low-carbon chemistry and consistent HSS geometry support welding, cutting, drilling, and galvanizing/painting preparation (process-dependent).

• Fit-up consistency: Standardized wall, corner radius, and squareness tolerances reduce rework during fabrication and erection.

Our Advantages (3 Procurement Questions Answered)

1. “Will the tubing fit my jigs and connection details?”
   We control the exact parameters that drive fit-up—wall tolerance (±10%), corner radius (≤3t), squareness (±2°), straightness, and length tolerances—so your gussets, baseplates, and splice details align with predictable HSS geometry.

2. “Can you provide compliance documents that pass QA/QC?”
   When required on the PO, we supply Certificates of Compliance and Test Reports including heat analyses and tension test results per ASTM A500, and we mark each length (or bundle tag for ≤4 in) with manufacturer ID, spec designation, and grade.

3. “What about weld seam/flash—will it affect fabrication or coating?”
   ASTM A500 ERW tubing is welded across thickness for structural design strength, and the outside weld seam must be free of protruding metal. Inside flash is normally not removed unless specified—so we can align supply with your needs (standard structural use vs. ID-sensitive applications).

Chemical Composition

Mechanical Properties

Standards

• ASTM: ASTM A500/A500M Grade C — cold-formed carbon steel structural tubing (HSS)

• ASTM (premium option): ASTM A1085 — higher-performance HSS with defined impact requirement

• EN: EN 10219-1/2 — cold formed welded structural hollow sections (technical delivery + tolerances/dimensions)

• GOST: GOST 30245 — welded square/rectangular closed sections for structural/building use

• JIS: JIS G 3466 — carbon steel square/rectangular tubes for general structure

• GB: GB/T 6728 — cold forming sectional steel for general structure

Application Fields

• Building & Civil Structures: columns, bracing members, trusses, lintels, handrail/guard frames

• Industrial Fabrication: equipment frames, skids, conveyors, racks, mezzanine structures

• Transportation: trailer frames, container frames, structural reinforcements

• Energy & Utilities: solar racking, sign structures, cable/pipe supports

Q: Are you trading company or manufacturer ?

A: manufacturer,also can do trading.

Q: How long is your delivery time?

A: Generally speaking,it is 10-15 days if the goods are in stock,or it is 30-40 days if the goods are not in stock,

it is according to quantity.

Q: Do you provide samples? is it free or extra ?

A: Yes, we could offer the sample for free charge but need pay the cost of freight.

Q: What is your terms of payment ?

A: Payment<=2000USD, 100% in advance. Payment>=2000USD, 30% T/T in advance ,balance before shippment.

If you have another question, pls feel free to contact with me.