AH36, DH36, and EH36 are high-strength shipbuilding steels with a guaranteed minimum yield of 355 MPa (51 ksi) and controlled low-temperature toughness requirements; they are the industry standard for hull, deck, and critical offshore structural members where strength plus notch toughness are mandatory. For procurement teams needing mill-certified, classification-approved plate with fast lead times and factory prices, MWAlloys supplies ABS/ASTM A131 / DNV / LR certified AH36–DH36–EH36 plates directly from China with 100% factory pricing and rapid stock shipment.

AH36, DH36 and EH36 belong to the H-series of shipbuilding steels developed to combine higher static strength with reliable low-temperature toughness. The numeric “36” indicates the minimum specified yield (in ksi) in traditional naming; modern metric expression is 355 MPa. The letter prefix denotes the required low-temperature Charpy V-notch test level: AH36 is intended for higher strength at standard temperatures, DH36 requires verified toughness at −20 °C, and EH36 requires verified toughness at −40 °C (used in colder waters and ice-class service).

Nomenclature and applicable standards

• Primary standard: ASTM A131 (Group 1 & Group 2 depending on thickness and heat treatment) defines the acceptance testing, mechanical properties and expectable delivery conditions for AH36/DH36/EH36.

• Classification societies: Plates are commonly supplied with ABS, DNV / DNV-GL, Lloyd’s Register (LR), Bureau Veritas (BV), and CCS certificates; many shipbuilders specify the classification society in contract.

• Delivery conditions & notations: Common delivery conditions include AR (as-rolled), TMCP (thermo-mechanical controlled processing, often noted as CR — control-rolled), N (normalized), and Q+T (quenched and tempered) where specified. These affect toughness and weldability.

Chemical composition (typical ranges)

Below is a summarized composition table that reflects commonly accepted mill chemistries used to meet AH36 / DH36 / EH36 requirements. Individual mills will publish exact composition on the mill test certificate (EN 10204 / 3.1 or 3.2) supplied with each heat.

(Table compiled from common mill specifications and supplier technical pages; always refer to the mill test report for the exact heat-by-heat composition).

Metallurgical note

Modern AH/DH/EH plates are usually produced using TMCP (controlled rolling + accelerated cooling) to obtain required strength and a fine ferrite-pearlite / bainitic microstructure that gives a superior combination of ductility and notch toughness without heavy alloying. Micro-alloy elements (Nb, V, Ti) are used to pin grain growth and enable higher strength at low carbon levels.

Mechanical properties & impact/toughness requirements

Notes

• The tensile/elongation bands vary with thickness and production route; EH36 often has a slightly higher upper tensile bound.

• Charpy test energy and test temperature are selected by grade and thickness; classification society rules and ASTM A131 give the detailed acceptance criteria.

Delivery conditions, dimensional ranges and specifications

Fabrication & welding notes

• Weldability: With C ≤ 0.18 and controlled Mn, AH/DH/EH steels are weldable with common consumables. Use matched strength consumables where joint strength is critical.

• Preheat & interpass: For plates thicker than ~30 mm, preheat (typically 120–150 °C) is often specified to control hydrogen cracking risk; for thickness ≤ 30 mm, ambient conditions and low hydrogen welding may allow reduced preheat but project specifications and ambient temperature requirements must be respected.

• Heat input: Keep heat input within the supplier/class limits; many mills provide “maximum heat input” guidance for each condition. TMCP steels tolerate relatively high heat input if the welding procedure is qualified.

• Post-weld treatment: PWHT is generally not required for AH36/DH36/EH36, unless the client or classification society specifically calls for it. Where fracture toughness or brittle crack arrest characteristics are specified (BCA steels), special testing and procedures apply.

Corrosion and coatings

AH/DH/EH are carbon-manganese steels; standard practice is to combine the base metal with protective coatings and cathodic protection in aggressive marine environments. Typical options:

• Surface preparation: shot-blast to Sa2½ when painting.

• Primers: epoxy zinc phosphate or zinc-rich primers for long life.

• Topcoats: polyurethane or polysiloxane systems for UV and abrasion resistance.

• For ballast tanks and internal structural compartments, high-build epoxy systems and periodic maintenance are routine.

Typical applications and selection advice

• Hull plating (main bottom, side shell) — where structural strength and toughness at operating temperatures must be assured.

• Decks and hatch coamings — DH/EH when colder service or ice impact risk exists.

• Offshore platforms and drilling units — chassis and cantilever structures requiring high static strength.

• Cranes and heavy deck gear — EH36 often used for crane booms because of higher toughness at low temps.

Selection tip: If the vessel operates in cold waters or will transit polar regions, specify DH36/EH36 with the corresponding Charpy acceptance temperature and seek mill control-rolled or normalized material to ensure consistent toughness.

2025 price comparison (China, United States, Europe)

Note: Plate prices vary with thickness, finish, certification, order quantity and regional transport costs. The table below presents representative market ranges collected from suppliers active in 2025; treat the figures as procurement benchmarks and request live quotations for firm planning.

How to interpret these numbers

• Lower end pricing typically reflects basic AR/TMCP plate with standard mill test certificates.

• Higher figures include additional processing (normalizing, Q+T), third-party classification stamping (ABS/DNV/LR/BV), tight flatness, shot-blast, or special packaging.

• Freight, inland transport, and duties can change landed cost materially; always request CIF/CPT and compare total landed cost to onshore options.

Why source AH36/DH36/EH36 from MWAlloys

• Factory direct pricing: MWAlloys sources AH36/DH36/EH36 directly from certified Chinese mills, passing on 100% factory prices without extra trader margins.

• Certificates and classification support: Standard mill certificates (EN 10204 3.1 / 3.2) and classification stamping (ABS / DNV / LR / BV / CCS) provided on request.

• Stock and fast delivery: MWAlloys maintains regular stock of common thicknesses and can organize export documentation and sea freight quickly for short lead-times.

• Quality control: Pre-shipment third-party inspection (SGS / BV) is available; welding and fabrication advice supplied by MWAlloys’ technical team for efficient shop production.

• After-sales: Technical follow-up on weld procedures, NDT witness, and certificate reconciliation.

Procurement & technical checklist

• Confirm classification society and required stamping.

• Specify delivery condition (AR / TMCP / N / Q+T).

• State required Charpy test temperature and acceptance energy.

• Request EN 10204 mill certificate type (2.2 / 3.1 / 3.2).

• Clarify surface treatment, end-use environmental class and coating system.

• Get weld procedure qualification limits (PQR) and maximum heat input from mill.

• Confirm lead time, MOQ and packaging for ocean shipment.

FAQs

1. What is the main difference between AH36, DH36 and EH36?
   The difference lies in the low-temperature Charpy test requirement and intended service temperature: AH36 is the baseline high-strength grade, DH36 requires verified toughness at −20 °C, EH36 at −40 °C.

2. Is AH36 the same as ASTM A131 Grade AH36?
   Yes; AH36 typically references the requirements found under ASTM A131 and accepted by classification societies like ABS.

3. Can AH36 be welded with standard steel welding consumables?
   Yes. Use suitable low-hydrogen electrodes or GMAW wires and follow recommended preheat/interpass rules for thickness.

4. Do I need post weld heat treatment (PWHT)?
   Generally no for AH/DH/EH plate. PWHT may be required only for specific welded assemblies or by classification when brittle crack arrest properties are mandated.

5. Which delivery condition is best for low-temperature service?
   TMCP (control-rolled) or normalized conditions are common for better low-temperature toughness; consult the mill and classification requirements.

6. How thick can AH36 plate be produced?
   Typical mills produce from ~4.76 mm up to 150 mm or more; availability depends on the mill.

7. What certifications do MWAlloys supply?
   Standard EN 10204 mill certificates (2.2 / 3.1 / 3.2), and classification stamping (ABS, DNV, LR, BV, CCS) on request.

8. How does price vary with thickness?
   Thinner plate often has higher per-ton processing costs; however, market premiums for special delivery conditions or extra testing can exceed thickness effects.

9. Is EH36 used only in polar vessels?
   No; EH36 is used where guaranteed toughness at −40 °C is needed: polar vessels, some offshore units, and heavy deck machinery exposed to cold climates.

10. How fast can MWAlloys ship standard AH36 plate from China?
    For stocked sizes, MWAlloys typically arranges shipment within days to a few weeks depending on volume and destination; exact lead times provided in quotation.

Practical engineering tips

• When designing large welded structures, allow for weld access and consider optimizing weld sequences to minimize restraint and reduce the risk of distortion.

• For brittle crack arrest concerns on very large hulls, consult classification society rules for BCA steels and consider higher-ductility (HD) designations.

Closing remarks

AH36/DH36/EH36 remain the workhorse grades for modern shipbuilding and offshore structures because they combine a known minimum static strength (355 MPa) with verifiable low-temperature toughness that supports safe operation in many environments. MWAlloys is positioned to support engineering and procurement teams with certified plate, mill documentation, and logistics solutions that reduce landed cost and shorten delivery cycles.