What is DH36 steel plate?
DH36 is the −20 °C member of the 36-series higher-strength hull steels: 355 MPa yield, 490–630 MPa tensile, 21 % elongation and a Charpy V requirement of 34 J longitudinal / 24 J transverse at −20 °C. To meet that toughness at thicknesses up to 80–100 mm the steel must be fully killed and fine-grain treated (aluminium plus niobium, vanadium or titanium) and, above 25–35 mm depending on the society and the micro-alloying route, delivered normalised, normalised-rolled or thermomechanically rolled rather than as rolled — the certificate states which. The societies\' material-class tables step from AH to DH as plate thickness and structural importance increase: in the highest class (sheer strake, stringer plate, bilge strake and rounded gunwale amidships, hatch corners, longitudinal hatch coamings) DH36 is required from around 20 mm, in the shell and strength deck from 25–40 mm, and for vessels with a design temperature below 0 °C — Baltic, North Sea, ice-class and polar-code ships — DH36 or EH36 replaces AH36 throughout exposed structure. The same applies to offshore platforms, jack-ups and FPSO hulls under the offshore rules. Fabrication is identical to AH36: approved 3Y consumables, no preheat to about 30 mm, cold forming at 3 × t, line heating below 600–650 °C. Because DH36 is often TM-rolled with a low carbon equivalent, it frequently welds more easily than an as-rolled AH36 of the same thickness. ASTM A131 DH36 is the same grade; S355J2 / S355N are the nearest structural equivalents.
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 | 375–420 MPa | |
| Tensile strength Rm | 490–630 MPa | 510–560 MPa | |
| Elongation A5 | ≥ 21 % | 24–30 % | |
| Charpy V longitudinal | ≥ 34 J at −20 °C | > 120 J | |
| Charpy V transverse | ≥ 24 J at −20 °C | > 80 J | |
| Delivery condition | AR (thin) / N / NR / TM | N or TM above ≈ 25–35 mm |
Equivalent grades
| System | Grade | Note |
|---|---|---|
| IACS / all societies | DH36 | LR DH36, BV DH36, DNV NV D36, ABS DH36, RINA DH36, TL DH36, NK KD36 |
| ASTM | A131 Grade DH36 | identical |
| EN 10025-2 / -3 | S355J2 / S355N (approx.) | no class certificate |
| EN 10025-4 | S355M | TM equivalent |
| JIS G3106 | KD36 | |
| GB 712 | DH36 | Chinese |
What the society certificate covers
For DH36 the certificate matters twice: it names the society whose surveyor witnessed the tests, and it states the delivery condition — as rolled, normalised, normalised-rolled or thermomechanical — that the −20 °C toughness was proven in and that the yard\'s welding procedures are qualified for. Plates are stamped with the society mark, "DH36", heat number and condition. Our mills are approved by LR, BV, DNV, ABS, RINA, Türk Loydu and ClassNK; tell us the society and whether the class plan calls for N or TM, and we quote the matching mill. Non-classed offshore fabrication can be supplied with a 3.1 certificate and, on request, 3.2 witnessing by an independent inspector.
AH36 or DH36 — thickness and zone
| Hull area | AH36 up to | DH36 up to | EH36 from |
|---|---|---|---|
| Internal structure, decks inboard (class I) | 30 mm | 50 mm | > 50 mm |
| Shell, bottom, strength deck outboard (class II) | 20–25 mm | 40 mm | > 40 mm |
| Sheer strake, stringer, bilge strake amidships (class III) | 15–20 mm | 25–30 mm | > 30 mm |
| Hatch corners, coaming tops, crane pedestals | 15 mm | 25 mm | > 25 mm |
| Design temperature ≤ −10 °C (ice class, polar) | not used exposed | per rules | per rules |
Values differ between societies and with ship length; the class-approved drawings and material plan are the reference.
Thickness range and stock sizes
| Thickness | Widths × lengths | Availability |
|---|---|---|
| 8–15 mm | 2 000 / 2 500 × 6 000 / 12 000 | stock and mill |
| 20–40 mm | 2 500 / 3 000 × 6 000 / 12 000 | stock and mill |
| 50–80 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) |
|---|---|---|---|---|
| 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.
Welding, cutting and fabrication
Weld with approved Grade 3Y consumables (MAG, FCAW, SAW, MMA); no preheat up to about 30 mm at CEV ≤ 0.40, 50–100 °C beyond; the −20 °C weld-metal impact is why Grade 3 rather than 2 consumables are specified. Follow the mill\'s heat-input limits for TM plate (typically ≤ 5 kJ/mm for one-sided SAW). Plasma and oxy-cutting, bevelling, cold forming at ≥ 3 × t and line heating below 600 °C (TM) / 650 °C (N) are standard yard practice; no post-fabrication normalising of TM plate.
Where it is used
- Sheer strake, deck stringer and bilge strake plates
- Thick shell and strength-deck plating of large vessels
- Hatch coamings, hatch corners and crane pedestals
- Ice-class and cold-water vessel hulls
- Offshore platforms, jack-ups, FPSO and wind-installation vessels
- Heavy structural members of dredgers and heavy-lift ships
DH36 vs AH36 vs EH36
AH36 is the same strength tested at 0 °C, sufficient for thinner and less critical plates; DH36 (−20 °C) is required as thickness and stress rise; EH36 (−40 °C) for the thickest and coldest service. Outside classed work, S355J2 gives the same strength and impact temperature with a 3.1 mill certificate.
Price
Quoted per lot on request; DH36 carries a premium over AH36 for normalising or 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
Packing for DH36 steel plate: plates banded on hardwood skids (max 5 t per pack), edges protected, heat numbers marked; A 40' HC takes 24–25 t of 6 m plate. Over-length plate is loaded flat-rack, and heavy plate above 25 t per piece travels breakbulk from Derince. HS 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 10–25 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 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
Documentation for DH36 steel plate: EN 10204 3.1 mill certificate as standard (heat number, analysis, tensile, Charpy, condition); 3.2 with an independent inspector, EN 10160 UT reports and additional low-temperature Charpy tests are available on plates above 8 mm at order.
How to order
Specify DH36, the society, thickness × width × length list, quantity, delivery condition (N / TM) if the class plan requires it, shop primer, and the vessel or project reference.
Standards
- IACS UR W11
- LR / BV / DNV / ABS / RINA / TL rules
- ASTM A131 Grade DH36
- Society certificate (3.2 equivalent)
Grades
Grade data sheets (chemistry, mechanicals, equivalents) are on our reference site: DH36 · AH36 · EH36
Frequently asked questions
What is DH36 steel?
Higher-strength shipbuilding steel with 355 MPa minimum yield and 34 J Charpy impact at −20 °C — required in thicker and more critical hull plates and in cold-water vessels; rolled at class-approved mills with the society certificate.
What is the difference between DH36 and AH36?
Identical strength; DH36 guarantees toughness at −20 °C (AH36 at 0 °C) and is usually normalised or TM-rolled above 25–35 mm. The rules require DH36 as thickness and stress increase.
What is the equivalent of DH36?
ASTM A131 DH36 is identical; S355J2 or S355N (EN 10025) are the nearest structural equivalents without class certification.
Does DH36 need preheat for welding?
Not up to about 30 mm with Grade 3Y consumables; 50–100 °C above that or in cold shops.
When is DH36 required instead of AH36?
By the society material-class tables: typically above 20 mm in the sheer strake and stringer, above 25–40 mm in shell and deck, and throughout exposed structure of ice-class and cold-climate vessels.