What are the grades of steel used in shipbuilding?
Short answer
| Strength class | IACS grades | Toughness progression |
|---|---|---|
| Normal | A → B → D → E | E has the lowest test temperature (highest toughness) |
| Higher | AH → DH → EH → FH | FH/EH for thick/weather-exposed plating |
- Grades: Normal-strength A, B, D, E; higher-strength AH, DH, EH, FH
- Toughness basis: Charpy impact test at specified temperatures; E and EH/FH offer highest low-temperature toughness
- Requirement: IACS Unified Requirement W11 defines grades and properties; UR I2 assigns minimum grades by hull location and thickness
- CE check: Verify mill certificates and class approval against IACS UR W11 and UR I2
Full answer
The full answer explains each point step by step, with the regulations and figures behind it and the discussion from other candidates. It is in the MEO Class I section of the Marine One forum, open to members enrolled for the MEO Class I exam.