What is AH32 steel plate?
AH32 sits between the normal-strength grades (A–E, 235 MPa) and the H36 series (355 MPa): 315 MPa minimum yield, 440–570 MPa tensile, Charpy 31 J longitudinal at 0 °C, delivered as-rolled up to 12.5 mm and normalised, controlled-rolled or thermo-mechanically rolled above, with fine-grain treatment by aluminium, niobium, vanadium or titanium. The steel is fully killed, carbon is held at 0.18 % maximum and manganese at 0.90–1.60 %, so the carbon equivalent stays low enough that no preheat is needed below 30 mm with low-hydrogen consumables. The H32 series exists because a 315 MPa plate lets a designer use a lower material factor (k = 0.78 against 1.0 for mild steel and 0.72 for H36) with more modest alloying and better fatigue behaviour at welded details than H36 — Japanese and Korean yards standardised on it for bulk-carrier and tanker hulls, and class rules for river-sea, ferry and offshore-supply tonnage frequently call it up throughout the hull. AH32 is the 0 °C member of the series; DH32 and EH32 carry the same strength to −20 and −40 °C. Every plate is rolled at a society-approved mill, stamped with the society mark, heat number and grade, and covered by the surveyor's certificate.
Chemical composition
| Element | C | Si | Mn | P | S | Al | Nb | V | Ti | Cu | Cr | Ni | Mo |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| max. % (ladle) | ≤ 0.18 | ≤ 0.50 | 0.90–1.60 | ≤ 0.035 | ≤ 0.035 | ≥ 0.015 (total) | 0.02–0.05 | 0.05–0.10 | ≤ 0.02 | ≤ 0.35 | ≤ 0.20 | ≤ 0.40 | ≤ 0.08 |
IACS UR W11 ladle analysis for the H32 series; grain refinement by Al, Nb, V or Ti singly or in combination. CEV ≤ 0.36 typical for TM plate, ≤ 0.38 normalised.
Mechanical properties
| Property | Requirement | Typical value | Note |
|---|---|---|---|
| Yield strength ReH | ≥ 315 MPa | 335–380 MPa | |
| Tensile strength Rm | 440–570 MPa | 460–520 MPa | |
| Elongation A5 | ≥ 22 % | 26–32 % | |
| Charpy V, longitudinal | ≥ 31 J at 0 °C | 60–120 J | t ≤ 50 mm; 22 J transverse |
| Charpy V, t 50–70 mm | ≥ 38 J at 0 °C | — | 50 J above 70 mm |
| Bend test | 180°, 3 t | passes | transverse |
Equivalent grades
| System | Grade | Note |
|---|---|---|
| ASTM A131 | AH32 | identical |
| LR | AH32 | Lloyd's Register |
| DNV | NV A32 | |
| BV | AH32 | |
| ABS | AH32 | |
| GL (legacy) | GL-A32 | |
| EN 10025-2 (approx.) | S315 — none; nearest S275J0 | not a substitute: no class certificate |
| JIS G3106 (approx.) | SM400 – SM490 range | commercial only |
Class approval and delivery condition
Ordering AH32 means ordering it under a named society: the mill's approval, the plate stamp and the certificate all carry that society's mark and a plate certified LR is not automatically accepted by a BV-classed yard. Turkish and EU mills we work with hold approvals for the H32 series with LR, BV, DNV, ABS, RINA and Türk Loydu; the delivery condition (AR / N / TM) is chosen by the mill within the rules for the thickness and is stated on the certificate — TM plate keeps the low carbon equivalent that makes AH32 easy to weld at thickness. For unclassed barges and pontoons the same chemistry can be sold with a 3.1 mill certificate only, at a lower price and a shorter lead time.
Thickness range and stock sizes
| Thickness | Widths × lengths | Availability |
|---|---|---|
| 6–12 mm | 2 000 / 2 500 × 6 000 / 8 000 | class-stock mills, 2–3 weeks |
| 15–30 mm | 2 000 / 2 500 / 3 000 × 6 000–12 000 | mill order 4–6 weeks |
| 32–80 mm | 2 500 / 3 000 × 6 000–12 000 | mill order 5–7 weeks |
| Cut / bevelled | plasma to 80 mm, oxy above; K/V bevels | from the nesting file |
Weight per m² and per plate
| Thickness | kg/m² | 1 500 × 6 000 (kg) | 2 000 × 6 000 (kg) | 2 500 × 12 000 (kg) |
|---|---|---|---|---|
| 6 mm | 47.1 | 424 | 565 | 1 413 |
| 8 mm | 62.8 | 565 | 754 | 1 884 |
| 10 mm | 78.5 | 707 | 942 | 2 355 |
| 12 mm | 94.2 | 848 | 1 130 | 2 826 |
| 15 mm | 117.8 | 1 060 | 1 413 | 3 533 |
| 20 mm | 157.0 | 1 413 | 1 884 | 4 710 |
| 25 mm | 196.3 | 1 766 | 2 355 | 5 888 |
| 30 mm | 235.5 | 2 120 | 2 826 | 7 065 |
| 40 mm | 314.0 | 2 826 | 3 768 | 9 420 |
| 50 mm | 392.5 | 3 533 | 4 710 | 11 775 |
| 60 mm | 471.0 | 4 239 | 5 652 | 14 130 |
| 80 mm | 628.0 | 5 652 | 7 536 | 18 840 |
Nominal weights — mill tolerance to EN 10029 class A adds up to +4 % on thin plate; invoiced on theoretical weight unless agreed otherwise.
Cutting, welding and shop primer
Plasma to 80 mm and oxy-fuel above, from the yard's nesting files; bevels 30–37.5° for hull butt welds. Welding: SMAW, FCAW and SAW with consumables of grade 2Y or 3Y (class-approved, 400 MPa class); preheat is not required below 30 mm at CEV ≤ 0.36, 50 °C above; heat input up to 3.5 kJ/mm on TM plate. The plate can be shot-blasted to Sa 2½ and shop-primed with a class-approved zinc silicate (15–20 µm) before delivery, with the stamp area masked or re-marked under survey.
Where it is used
- Shell, deck and bulkhead plating of bulk carriers and tankers built to the H32 series
- Ferries, river-sea vessels and offshore supply craft
- Hatch coamings and cover plates
- Barges and pontoons (with or without class)
- Repair plate where the original hull is H32
AH32 vs AH36 vs Grade A
AH36 gives 355 MPa — 13 % more strength for a few percent more per ton, and is the more common higher-strength grade in European yards; AH32 wins where the design is already based on k = 0.78 or where the yard wants the easier welding and better fatigue ratio. Grade A is the 235 MPa mild-steel baseline, used where thickness is set by stiffness or corrosion margin rather than strength. For cold-water tonnage the same 315 MPa is available as DH32 (−20 °C) and EH32 (−40 °C).
Price
Class-certified plate is quoted per certificate lot rather than from a list band: AH32 sits a few percent below AH36 and 5–10 % above Grade A of the same thickness, plus the society survey fee per lot. Send the plate list with society and delivery condition for a firm price within a working day.
Bands from our weekly export list (September 2026), FOB Istanbul, full-container quantities, excluding freight and certificates. Firm price per project on RFQ within one working day.
Export and packing
AH32 steel plate is packed as follows: plates on bearers, banded, stamped; primed plates with separators. Loading: 20' ≈ 20 t; 40' HC ≈ 24 t; 12 m and heavy plate breakbulk from Derince. Customs classification is by surface and alloy content — 7208, 7209, 7210, 7225 or 7226.
| Term | Detail |
|---|---|
| MOQ | 5 t per size; 20 t per certificate lot |
| Incoterms | FOB Istanbul · CIF / CFR Gulf, Africa · DAP EU, Balkans, Iraq, Caucasus · DAP Aktau |
| Lead time | Class stock 8–25 mm: 2–3 weeks; mill order 4–6 weeks |
| Packing | Plates on bearers, banded, stamped; primed plates with separators |
| Container / truck | 20' ≈ 20 t; 40' HC ≈ 24 t; 12 m and heavy plate breakbulk from Derince |
| Documents | Invoice, packing list, EN 10204 3.1 (3.2 on request), certificate of origin; SASO / SONCAP / PVoC on request |
| Payment | 30% advance, balance against B/L copy; L/C at sight for orders above 100 t |
Certificates and testing
The paperwork travelling with AH32 steel plate is an EN 10204 3.1 certificate covering chemistry, mechanical values and the delivery condition. Third-party 3.2 certification by Lloyd's, BV, TÜV or SGS is ordered per lot. Ultrasonic testing to EN 10160 and extra Charpy tests at a lower temperature are priced separately.
How to order
Specify AH32, the society, thickness × width × length or the nesting list, delivery condition if the rules fix it (N / TM), shop primer, quantity and port; state whether 3.2 society certification or a 3.1 mill certificate (unclassed) is required.
Standards
- IACS UR W11
- LR / BV / DNV / ABS / RINA / TL rules
- ASTM A131 Grade AH32
- Society certificate (3.2 equivalent)
Grades
Grade data sheets (chemistry, mechanicals, equivalents) are on our reference site: AH32 · AH36 · DH32
Frequently asked questions
What is AH32 steel?
A higher-strength shipbuilding steel with 315 MPa minimum yield and 440–570 MPa tensile, impact-tested at 0 °C, killed and fine-grain treated, certified by a classification society (LR, BV, DNV, ABS, RINA, TL) to IACS UR W11 / ASTM A131.
What is the difference between AH32 and AH36?
Yield: 315 against 355 MPa; tensile 440–570 against 490–630 MPa. Same chemistry limits and impact temperature (0 °C); AH36 is stronger, AH32 has a lower yield ratio and slightly easier welding. The design series (k factor) decides.
Is AH32 weldable without preheat?
Yes below about 30 mm with low-hydrogen class-approved consumables at a carbon equivalent up to 0.36; above that 50 °C preheat is usual.
Which classification societies can certify AH32?
Lloyd's Register, Bureau Veritas, DNV (as NV A32), ABS, RINA and Türk Loydu; dual-certified plate (BV/LR, DNV/ABS) is common from the mills we use.
What thicknesses are available?
6–80 mm; 8–25 mm from class stock in 2–3 weeks, other thicknesses to mill order in 4–6 weeks, cut and bevelled at Dilovası.