What it is
Heavy steel plate is thick flat steel for structural fabrication, shipbuilding, pressure vessels, and machinery. Grade and impact-test class drive both safety and price, so substituting a cheaper grade or a lower impact class is the main fraud vector.
Grades & standards buyers order
| Grade | Standard | Notes |
|---|---|---|
| Q345B / Q355B | GB/T 1591 | Chinese low-alloy structural plate; the letter is the impact class. |
| S355JR / J2 | EN 10025 | European structural grade; JR vs J2 = impact test temperature. |
| A36 / A516 Gr.70 | ASTM | US structural and pressure-vessel plate. |
How it's sold: Sold by metric ton; specify grade, impact class, thickness and tolerance, and surface/edge condition. Confirm plate marking and heat traceability.
What drives the price
- Grade and alloy content
- Impact-test class (J2 costs more than JR)
- Thickness and tolerance
- Plate size and cut-to-size work
Lock these into the contract before you pay
Grade AND impact class
S355JR and S355J2 are priced and tested differently; specify the exact suffix.
Thickness tolerance
Rolling to minus tolerance ships less steel per ton.
Heat number / plate marking
Each plate should carry a heat number matchable to the certificate.
Scams most common to steel plate
Grade Substitution (lower grade shipped than ordered)
A cheaper grade or lower impact class shipped as the ordered structural/vessel grade.
Forged Mill Test Certificates (MTC / EN 10204 3.1)
Certificate grade, impact values, and heat number that do not match the plate.
Grade Substitution (lower grade shipped than ordered)
Pressure-vessel plate replaced with ordinary structural plate — a serious safety fraud.
Red flags in a quote or sample
- Impact class omitted (grade with no JR/J2/B suffix)
- No heat number or plate marking in photos
- Vessel-grade price matching ordinary structural plate
Already paid and something's wrong?
If you received off-spec steel plate, a certificate that doesn't match, or your supplier has gone quiet after a deposit, move quickly. Recovery odds drop with every day that passes on a wire transfer.
Buying steel plate from China: FAQ
What grades of steel plate can I buy from China?
The most commonly ordered grades are Q345B / Q355B, S355JR / J2, A36 / A516 Gr.70. Always pair the grade with its standard on the purchase order so the mill test certificate can be matched to what you actually receive.
What is the most common scam when buying steel plate from China?
Grade Substitution (lower grade shipped than ordered). For this product specifically: A cheaper grade or lower impact class shipped as the ordered structural/vessel grade. The defense is to specify the exact grade and standard, require a verifiable mill test certificate, and commission independent pre-shipment inspection.
What should I check before paying for steel plate?
Lock down grade and impact class, thickness tolerance, heat number / plate marking in the contract, verify the supplier is a real manufacturer, and never release the balance until an independent inspection confirms the goods.
I already paid a Chinese supplier for steel plate — what now?
Act fast: contact your bank about a recall on the wire, gather all contracts and communications, report the pattern so others are warned, and review the documented cases to understand your options. The sooner you act on a redirected or disappeared payment, the better the odds.
Related product guides
HR coil
The base flat product for tubes, plate, and re-rolling. Grade substitution and thickness/gauge shortfall are the primary risks.
H-beam
Hot-rolled structural sections for buildings. Section-weight (kg/m) shortfall and grade substitution are the main risks.
Seamless pipe
Pipe with no weld seam for pressure and boiler service. Seamless-vs-welded substitution and wall-thickness shortfall are critical safety risks.