Technical guide · 2026-08-03
Shipbuilding Steel
Shipbuilding steels are hull plate and section grades supplied under classification-society rules and approved manufacturing routes. Normal- and higher-strength grades combine strength level with toughness category, thickness, delivery condition and survey traceability for the intended hull location.
01
Definition and boundary
AH36 is not simply “A36 with H”: ASTM A36 structural steel and classification-grade AH36 follow different designation, testing and certification systems.
Reference information only: final acceptance is controlled by the ordered product specification, condition, dimensions and certified test results.
02
How the material system works
Composition, grain refinement and rolling/heat treatment provide strength and toughness.
A/D/E toughness categories relate to required impact performance and test temperature within class rules.
TMCP can deliver higher strength/toughness with controlled weldability for specific products.
03
Representative grades and systems
| Grade or system | Selection focus | Qualification |
|---|---|---|
| A/B/D/E | Normal-strength hull grades differentiated by toughness requirements. | Verify the ordered product specification, condition and dimensions before substitution. |
| AH36/DH36/EH36 | Higher-strength hull grades with different toughness categories. | Verify the ordered product specification, condition and dimensions before substitution. |
| FH36 and higher-strength series | Special toughness/strength choices requiring class and thickness confirmation. | Verify the ordered product specification, condition and dimensions before substitution. |
04
Properties and trade-offs
Strength grade and toughness letter must be read together.
Thickness and delivery condition affect guaranteed properties.
Weld heat input and consumable matching are controlled for critical joints.
05
Product forms and supply conditions
06
Applications and selection
Applications and selection
- Hull shell, deck, bulkhead and internal structure
- Offshore platforms and marine structural modules
- Highly stressed thick plate regions under approved rules
Properties and trade-offs
- Follow the selected classification society and vessel rule set.
- Map hull location, thickness and design temperature to grade/toughness category.
- Confirm approved mill, manufacturing route, weld procedure and survey documentation.
07
Fabrication, durability and inspection
Use qualified welding procedures based on carbon equivalent, thickness, restraint and hydrogen control.
Account for rolling direction, residual stress, heat-affected-zone properties and distortion.
Apply coating, drainage, corrosion allowance or another material strategy for the actual exposure.
08
Procurement checklist
- State the governing product specification, grade, dimensions, tolerances and delivery condition.
- Define impact testing, NDE, through-thickness, heat treatment, weldability and traceability when applicable.
- Request an MTC tied to heat/lot identity and list all supplementary requirements in the purchase order.
09
Standards, sources and review
Standards and designation context
- IACS Common Structural Rules where applicable
- Individual classification-society material and welding rules
- Project coating, fabrication and inspection specifications