Technical guide

EN 10219 vs ASTM A500 vs GB/T 6728

The same 200×200×8 tube can be made to three different standards, and the certificate wording changes with it. If your drawing cites EN 10219 or ASTM A500, this is what the mill actually has to control.

What each standard covers

Where they actually differ

Tolerance, not strength. All three can be supplied in 355 MPa class steel; the difference is how much the section may deviate. ASTM A500 is the most permissive on squareness (±2°), EN 10219 the strictest on dimension control, GB/T 6728 the strictest on straightness.

Impact testing is where certificates diverge most: EN 10219 with a J2/H suffix requires charpy testing at −20 °C; A500 Gr.C does not require impact testing at all unless you ask. If your project is in a cold climate, the EN route is the one that produces paper you can defend.

How we map a requirement

1. You cite the standard and grade, e.g. EN 10219 S355J2H
2. We roll to GB/T 6728 geometry with Q355D steel chemistry, which meets or exceeds the EN mechanical requirements including −20 °C impact
3. The certificate states both the GB grade and the EN equivalence, with heat number, chemistry, tensile, impact and dimensional results
4. If a third-party inspection (SGS/BV) is required, it is booked 7 days before shipment

For projects that specify "A500 Gr.C" we supply Q355B with an MTR showing yield ≥ 355 MPa and note the ASTM equivalence; if the client's engineer needs the exact ASTM wording, we arrange third-party re-certification.

What to put on the drawing

Be explicit — "steel tube, good quality" produces a generic certificate that gets rejected at site:

• Standard + grade + impact class
• Tolerance class if tighter than standard
• Certificate type (3.1 / 3.2 / MTR)
• Coating standard (EN ISO 1461 for galvanising)

Our default if nothing is stated: GB/T 6728, Q355B, EN 10204 3.1 certificate, ±10 % wall.

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