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 |
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-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
Export packing of DH32 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 | 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. Third-party 3.2 certification (Lloyd's, BV, TÜV, SGS), ultrasonic testing to EN 10160 and extra Charpy tests at a lower temperature are ordered per lot.
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.