What is AH36 steel plate?
AH36 belongs to the higher-strength hull-steel family that IACS defines in three strength levels — 32 (315 MPa), 36 (355 MPa) and 40 (390 MPa) — each in four toughness grades A (0 °C), D (−20 °C), E (−40 °C) and F (−60 °C). AH36 is therefore 355 MPa yield, 490–630 MPa tensile, 21 % elongation and 34 J Charpy at 0 °C (24 J transverse), and it is by far the most used of the twelve. The strength comes from a fully killed, fine-grain carbon-manganese steel (C ≤ 0.18 %, Mn 0.90–1.60 %) micro-alloyed with niobium, vanadium and/or titanium and delivered as rolled, normalised or — increasingly — thermomechanically rolled (TM), which keeps the carbon equivalent low enough for the same shipyard welding procedures as Grade A. A hull designed in AH36 instead of Grade A/B uses plates 10–20 % thinner in the shell, strength deck, longitudinal bulkheads and hatch coamings; on a 180 m bulk carrier that is several hundred tons of steel and a corresponding gain in deadweight, which is why AH36 is the standard grade of bulk carriers, tankers, container ships, offshore supply vessels and jack-up legs. It is rolled at class-approved mills, tested under the surveyor and stamped and certified like every hull steel, and the mill certificate states the deoxidation and rolling practice. ASTM A131 AH36 is the identical US grade; S355J0 is the nearest non-class structural equivalent.
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 |
Ladle analysis; fine-grain practice with Al (≥ 0.015 % total) for the higher grades. Carbon equivalent CEV ≤ 0.40 for the 36 grades (≤ 0.38 for TMCP).
Mechanical properties
| Property | Requirement | Typical value | Note |
|---|---|---|---|
| Yield strength ReH | ≥ 355 MPa | 380–430 MPa | |
| Tensile strength Rm | 490–630 MPa | 520–570 MPa | |
| Elongation A5 | ≥ 21 % | 24–30 % | |
| Charpy V longitudinal | ≥ 34 J at 0 °C | > 100 J | |
| Charpy V transverse | ≥ 24 J at 0 °C | > 70 J | |
| Delivery condition | AR / N / TM per thickness | TM common ≤ 50 mm |
Equivalent grades
| System | Grade | Note |
|---|---|---|
| IACS / all societies | AH36 | LR AH36, BV AH36, DNV NV A36, ABS AH36, RINA AH36, TL AH36, NK KA36 |
| ASTM | A131 Grade AH36 | identical |
| EN 10025-2 | S355J0 (approx.) | no class certificate |
| EN 10025-4 | S355M (TM, approx.) | |
| JIS G3106 | KA36 | |
| GB 712 | AH36 | Chinese |
| Same strength, colder | DH36 / EH36 | −20 / −40 °C |
Class approval and mill certificate
Higher-strength grades carry one extra line on the society certificate: the deoxidation and rolling practice (killed, fine-grain; AR, N, NR or TM), because the toughness depends on it. The rest is standard hull-steel procedure — a society-approved mill, tests witnessed by the surveyor, the society mark and grade "AH36" stamped on every plate, and the certificate issued in the society\'s name. We confirm the approved mill for LR, BV, DNV, ABS, RINA, Türk Loydu or ClassNK before quoting, since an ABS approval is of no use on a DNV-classed vessel. Yards building outside class can take the identical plate with an EN 10204 3.1 certificate.
Higher-strength hull grades at a glance
| Grade | Yield (MPa) | Tensile (MPa) | Charpy (long.) | Typical use |
|---|---|---|---|---|
| AH32 / DH32 / EH32 | 315 | 440–570 | 31 J at 0 / −20 / −40 °C | less common, some Asian yards |
| AH36 | 355 | 490–630 | 34 J at 0 °C | general hull, decks, shell |
| DH36 | 355 | 490–630 | 34 J at −20 °C | thick plate, sheer strake, cold service |
| EH36 | 355 | 490–630 | 34 J at −40 °C | highest-stress zones, ice-class, offshore |
| FH36 | 355 | 490–630 | 34 J at −60 °C | arctic, LNG deck structures |
| AH40 / DH40 / EH40 | 390 | 510–660 | 41 J | container ships, large tankers |
The grade per plate is fixed by the society material-class tables (thickness × hull zone × service temperature) on the class-approved drawings.
Thickness range and stock sizes
| Thickness | Widths × lengths | Availability |
|---|---|---|
| 6–12 mm | 2 000 / 2 500 × 6 000 / 8 000 / 12 000 | stock and mill |
| 15–30 mm | 2 000 / 2 500 / 3 000 × 6 000 / 12 000 | stock and mill |
| 40–60 mm | 2 500 / 3 000 × 6 000 / 12 000 | mill order |
| Shop primer | Sa 2½ + 15–25 µm zinc silicate / epoxy | on request |
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 |
Nominal weights — mill tolerance to EN 10029 class A adds up to +4 % on thin plate; invoiced on theoretical weight unless agreed otherwise.
Welding, cutting and fabrication
AH36 is welded with society-approved Grade 3Y (or 2Y) consumables by MAG, FCAW, SAW and MMA without preheat up to about 30 mm (CEV ≤ 0.40) and with 50–100 °C above that or in cold shops; heat input up to 3.5–5 kJ/mm is acceptable for TM plate per the mill\'s data. Plasma and oxy-cutting, bevelling and cold forming (≥ 3 × t) are routine; line heating for fairing must stay below 650 °C (TM plate: 600 °C), and no normalising after fabrication. Shop-primed plates are supplied with type-approved weld-through primers.
Where it is used
- Shell, bottom and strength-deck plating of bulk carriers, tankers and container ships
- Longitudinal bulkheads, hatch coamings and girders
- Offshore supply vessels, jack-up and platform structures
- Ferries, ro-ro decks and large yachts
- Dredgers, heavy-lift and crane vessels
- Naval auxiliary and patrol vessel hulls
AH36 vs Grade A vs DH36
Grade A is 235 MPa — 50 % weaker — and the choice for smaller vessels where weight does not pay; AH36 is the standard for anything over roughly 100–120 m. DH36 is identical in strength with impact guaranteed at −20 °C, required in thicker and more critical plates; EH36 at −40 °C for the most demanding zones.
Price
Quoted per lot on request; AH36 carries a premium over Grade A for the micro-alloying and, where applicable, TM rolling, and the society certificate, plate size and shop primer are priced in. Send the plate list from the class plan for a firm offer 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
Export packing of AH36 steel plate is by skid: up to 5 t per pack, steel straps, corner boards, stencilled heat numbers and a pack list that references the 3.1 certificates. Container loading: 40' HC ≈ 24–25 t of 6 m plate, 20' ≈ 20 t of short plate. Long and heavy plate is shipped flat-rack or breakbulk via Derince. HS code 7208.51 / 7208.52.
| 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 | Stock 8–20 mm: 1–2 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 plate breakbulk / flat-rack 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
Every lot of AH36 steel plate carries an EN 10204 3.1 inspection certificate listing heat, chemistry, mechanical and impact results. On request we add 3.2 witnessing by a classification society or inspector, EN 10160 ultrasonic testing and supplementary impact tests at the customer's design temperature.
How to order
Specify AH36, the society, thickness × width × length list, quantity, delivery condition if required (N / TM), shop primer, and the vessel or project reference for the certificate.
Standards
- IACS UR W11 — higher-strength hull structural steels
- LR / BV / DNV / ABS / RINA / TL rules
- ASTM A131 Grade AH36
- Society certificate (3.2 equivalent)
Grades
Grade data sheets (chemistry, mechanicals, equivalents) are on our reference site: AH36 · DH36 · EH36
Frequently asked questions
What is AH36 steel?
Higher-strength shipbuilding steel with 355 MPa minimum yield, 490–630 MPa tensile and 34 J impact at 0 °C — the most used hull grade for ships over about 100 m, rolled at class-approved mills with the society certificate.
What is the equivalent of AH36?
ASTM A131 AH36 is identical; the nearest structural equivalent without class certification is S355J0 (EN 10025-2). All societies use the same designation (LR AH36, ABS AH36, DNV NV A36…).
What is the difference between AH36 and DH36?
Same strength and chemistry; DH36 guarantees the 34 J impact at −20 °C instead of 0 °C and is required in thicker plates and more critical hull zones.
What is the yield strength of AH36?
355 MPa minimum (typically 380–430), tensile 490–630 MPa, elongation ≥ 21 %.
Does AH36 need preheat for welding?
Not up to about 30 mm with approved Grade 3Y consumables; above that or in cold conditions, 50–100 °C.
Can you supply AH36 with a specific classification society certificate?
Yes — LR, BV, DNV, ABS, RINA, Türk Loydu or ClassNK from a mill approved by that society.