What is DH32 steel plate?
DH32 is the −20 °C member of the 315 MPa hull-steel series. Chemistry is identical to AH32 — 0.18 % carbon maximum, 0.90–1.60 % manganese, aluminium fine-grain practice with niobium, vanadium or titanium — but the delivery condition is restricted: normalised (N), controlled-rolled (CR) or thermo-mechanically rolled (TM), never as-rolled, because the guaranteed 31 J at −20 °C needs the fine ferrite-pearlite structure those routes give. In the IACS toughness tables the D grade is required as plate thickness and structural criticality rise: for a typical bulk carrier the sheer strake, bilge strake and deck stringer above about 20 mm move from AH32 to DH32, and vessels with ice-class notation or trading in Baltic and Black Sea winters use D-grade plating throughout the exposed hull. The −20 °C test temperature also makes DH32 the H32 grade for offshore modules, jack-up legs of lighter design and harbour craft in cold climates. Plates are rolled at society-approved mills, stamped with the society mark, heat number and grade and released on the surveyor's certificate; mills we use hold approvals for DH32 with LR, BV, DNV, ABS, RINA and Türk Loydu and frequently dual-certify.
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 −20 °C | 60–120 J | t ≤ 50 mm; 22 J transverse |
| Charpy V, t 50–70 mm | ≥ 38 J at −20 °C | — | 50 J above 70 mm |
| Bend test | 180°, 3 t | passes | transverse |
Equivalent grades
| System | Grade | Note |
|---|---|---|
| ASTM A131 | DH32 | identical |
| LR | DH32 | |
| DNV | NV D32 | |
| BV | DH32 | |
| ABS | DH32 | |
| GL (legacy) | GL-D32 | |
| EN 10025-2 (approx.) | S275J2 | no class certificate — not a substitute |
| EN 10025-3 (approx.) | S275N | normalised structural, commercial only |
When the rules require D instead of A
| Hull member | Thickness ≤ 15 mm | 15–20 mm | 20–25 mm | 25–30 mm | 30–40 mm |
|---|---|---|---|---|---|
| Deck and shell plating, general | AH32 | AH32 | AH32 | DH32 | DH32 |
| Sheer strake, deck stringer | AH32 | DH32 | DH32 | EH32 | EH32 |
| Bilge strake | AH32 | DH32 | DH32 | DH32 | EH32 |
| Hatch coamings, stringers in tanks | DH32 | DH32 | DH32 | EH32 | EH32 |
| Ice-belt plating (ice class) | DH32 | DH32 | EH32 | EH32 | EH32 |
Illustrative for Class I–III members; the society's material class table and the vessel's design temperature govern. We select the grade from the yard's plate schedule, not from this table.
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) |
|---|---|---|---|---|
| 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 |
Weights are theoretical. EN 10029 class A allows up to +4 % on thin plate, and unless the contract says otherwise the invoice follows the theoretical figure, not the weighbridge.
Cutting, welding and shop primer
Plasma-cut to 80 mm from the nesting file with K, V or X bevels; oxy-fuel above. Welded with class-approved grade 3Y consumables (SMAW, FCAW, SAW); preheat 50 °C from 30 mm or where the combined thickness exceeds 60 mm; heat input on TM plate limited to about 3.5 kJ/mm so the −20 °C toughness of the HAZ is kept — the certificate states the condition and the yard's WPS follows it. Shop primer: Sa 2½ blast and class-approved zinc silicate 15–20 µm, stamps re-marked under survey.
Where it is used
- Sheer, bilge and deck stringer plates of H32-series hulls
- Ice-belt and exposed shell plating for ice-class and winter trading
- Hatch coamings and tank stringers above 20 mm
- Offshore modules and light jack-up structures at −20 °C design temperature
- Cold-climate harbour craft, tugs and ferries
DH32 vs AH32 vs DH36
AH32 is the same steel tested at 0 °C and allowed as-rolled — cheaper and quicker for the general plating of a hull. DH36 gives 355 MPa at the same −20 °C for hulls designed to the H36 series; the two D grades are never mixed in one structure without the designer's approval because the material factor differs. EH32 takes the same strength to −40 °C for the most critical plates.
Price
DH32 is quoted per certificate lot: typically 3–6 % above AH32 for the normalising or TM route and the −20 °C test, plus the society survey fee. A plate list with society and required condition returns 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
How DH32 steel plate leaves Dilovası: 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. The HS heading depends on the product: 7208 / 7209 / 7210 for carbon strip, 7225 / 7226 where alloyed.
| 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 10–25 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
DH32 steel plate is delivered with the mill certificate EN 10204 3.1 — heat number, ladle analysis, tensile and impact results and the delivery condition. Where the client's QA requires it we book 3.2 inspection before rolling rather than after. We can add EN 10160 ultrasonic examination and Charpy sets at the temperature you nominate.
How to order
Specify DH32, the society, thickness × width × length or the nesting list, delivery condition (N / TM) where the yard requires one, shop primer, quantity and port; add UT (EN 10160 / society class) for plates that will carry through-thickness loads.
Standards
- IACS UR W11
- LR / BV / DNV / ABS / RINA / TL rules
- ASTM A131 Grade DH32
- Society certificate (3.2 equivalent)
Grades
Grade data sheets (chemistry, mechanicals, equivalents) are on our reference site: DH32 · AH32 · EH32
Frequently asked questions
What is DH32 steel?
Higher-strength shipbuilding steel with 315 MPa yield and 440–570 MPa tensile, impact-tested at −20 °C (31 J), supplied normalised or TM-rolled and certified by a classification society.
What is the difference between AH32 and DH32?
Same strength and chemistry; DH32 is tested at −20 °C instead of 0 °C and must be normalised or TM-rolled. The class rules require D grade for thicker and more critical plates and for cold-water operation.
When is DH32 required instead of AH32?
Typically for sheer strake, bilge strake and deck stringer above 15–20 mm, coamings, and throughout the hull for ice-class or low design temperatures — per the society's material class table.
Can DH32 be welded with the same consumables as AH32?
Class-approved grade 3Y consumables are used to keep the −20 °C toughness in the weld; heat input on TM plate is limited to about 3.5 kJ/mm and preheat of 50 °C applies from 30 mm.
Which societies certify DH32?
LR, BV, DNV (NV D32), ABS, RINA and Türk Loydu; plates are stamped and covered by the surveyor's certificate, dual certification on request.