Chinese Steel Grade Equivalents: EN, ASTM, AS/NZS & JIS Comparison

Engineers buying steel from China face the same question every day: what is the Chinese equivalent of AR400, S690QL or A514? The short answer: equivalents are approximate by design. Chinese GB standards, European EN standards, American ASTM standards and Japanese JIS standards specify steels differently, and matching a foreign grade is an engineering judgement — not a lookup.

Three differences that matter most

1. Impact energy requirements. For the same -20℃ grade, GB/T 1591 requires ≥34 J while EN 10025-2 requires ≥27 J. A Q355D plate exceeds the S355J2 impact requirement by design — for buyers this is an advantage, not a gap.

2. Delivery process. S700MC (EN 10149-2) is delivered as-rolled TMCP, while Baosteel BS700MCK2 undergoes an additional heat-treatment step after rolling: the plate comes out flatter with more uniformly released internal stress — critical for laser cutting and precision fabrication. Same strength class, different (and arguably better) plate geometry.

3. Wear steels are matched by hardness, not strength. NM400 corresponds to AR400 / HARDOX 400 / XAR 400 because all four guarantee 370–430 HBW surface hardness — yet each mill's chemistry and heat treatment route differs.

All comparisons below are cross-checked against the Handbook of Comparative World Steel Standards and current GB/EN/ASTM standard texts. Final grade selection should always follow the design documents and the actual mill certificate.

Every Q-grade is read in three parts. Using Q690D as the example:

A Q-grade in three parts

Impact temperature codes (GB/T 1591)

So Q690D = yield ≥690 MPa, Charpy impact guaranteed at −20℃. Q690E is the same steel certified for −40℃.

Beyond the Q series

One letter is worth watching in cold-climate projects: a Q355D plate exceeds the S355J2 impact requirement by design (≥34 J vs ≥27 J at −20℃) — the Chinese grade is not a downgrade.

GB/T 709-2019 is China's dimension and tolerance standard for hot-rolled plate — a modified adoption of EN 10029:2010. The framework is the same, but the class letters are reshuffled and most GB tolerance bands are equal or tighter than the EN equivalents. Values below are for trimmed-edge plate, width 1 500–2 500 mm, thickness 8–100 mm — the range Baohui stocks.

How the class letters map

Thickness tolerance, mm (width 1 500–2 500 mm)

Notes: in both standards classes B and C are single positive values — the minus deviation is fixed at −0.30 mm (B) or 0 mm (C). *EN 10029 uses different thickness steps above 40 mm (40–80, 80–150); the value shown is the EN band covering the GB step. GB values for width ≤1 500 mm are tighter still (e.g. 20 mm Class N: ±0.65 mm).

Flatness, mm — GB PF.A vs EN 10029 Class N

Values are identical in GB/T 709 (PF.A, normal) and EN 10029 (Class N), except † steel type H >40 mm on a 2 000 mm straight edge: GB allows 12 mm, EN 11 mm — the one cell where EN is tighter. If the wave pitch is 300–1 000 mm, both standards allow 1.0 % (type L) or 1.5 % (type H) of the pitch, capped at the table values.

Improved flatness: GB PF.B vs EN Class S

For plate >8 mm both match: 3 mm on a 1 000 mm straight edge, 6 mm on 2 000 mm (type L). EN Class S adds a tighter thin-plate option (4/8 mm at 3–8 mm, width <2 750 mm) where GB PF.B gives 5/10 mm. For type H plate, EN Class S must be agreed at the time of order, while GB PF.B publishes fixed values (7 mm at 1 000 mm for 8–15 mm, easing to 6 mm above 40 mm).

Which steel type are our plates?

Takeaway for buyers: ordered to the same class letter, GB/T 709 is equal or tighter than EN 10029 in nearly every cell — a 20 mm plate to GB Class N measures ±0.75 mm (±0.65 mm at width ≤1 500 mm) against EN Class D ±0.95 mm, and GB Class B (+1.20/−0.30) is much tighter than EN B (+1.6/−0.3). Plate produced to GB tolerances passes a routine EN 10029 receiving inspection. State the class in the purchase contract (GB default: N; EN default: A). For laser cutting and fine blanking, order improved flatness (GB PF.B / EN Class S) — or specify BS700MCK2, whose additional heat treatment delivers measurably better as-delivered flatness than as-rolled S700MC. Length tolerance (GB/T 709): +20/0 mm for 2 000–4 000 mm plate, up to +50/0 mm at 8 000–10 000 mm.

Wear-resistant (abrasion-resistant) plates are specified by hardness class (HBW) rather than yield strength. The NM series (GB/T 24186) covers the 400–600 HBW range; international buyers usually know these plates by their AR / HARDOX / XAR / RAEX names.

Notes: NM500 under Baosteel's enterprise standard is 470–530 HBW, slightly tighter than the GB range. Wear plates in stock are supplied with original mill test certificates — see weekly stock list with FOB prices.

High-strength structural plates are specified by minimum yield strength and impact temperature. Chinese Q and BS grades map to EN 10025 / EN 10149 and ASTM A572 / A514 grades as follows.

Notes: GB/T 1591 impact requirements exceed EN 10025 at the same temperature class (≥34 J vs ≥27 J). BS700MCK2 is delivered to Baosteel enterprise standard QBQB 316 with an extra heat-treatment step compared with as-rolled S700MC — preferred where plate flatness and stable internal stress matter (laser cutting, fine blanking). High-strength stock with weekly FOB prices: high-strength steel stock list →.

When you receive a mill test certificate (MTC) from a Chinese supplier, check three things before paying:

1. Standard number must match the grade. The certificate header should state both the standard (e.g. GB/T 1591-2018) and the grade (e.g. Q690D). A Q690D plate certified only to a mill's internal agreement is not the same product.

2. Read the measured values, not just the pass/fail. Yield strength, tensile strength and impact energy are reported as measured values. Values hugging the lower limit indicate batch instability; trustworthy mills report comfortable margins.

3. For export, look at EN 10204 document type. EN 10204 3.1 means the inspection document is validated by the mill's authorised inspection representative and is traceable to the heat number — the routine requirement for export projects. 3.2 adds independent third-party validation.

Baohui Steel ships every plate with the original mill certificate, and sample MTCs (with heat numbers) are available for download on each product page.