GL Rules Section 3 — GL Marine Structural Steel Specification
Grades
普通强度: A, B, D, E; 高强度: AH32, DH32, EH32, FH32, AH36, DH36, EH36, FH36, AH40, DH40, EH40, FH40
Chemical composition and mechanical properties
| Grade | Chemical composition | Mechanical properties |
|---|---|---|
| D | C≤0.21, Mn≥0.60(>25mm), P≤0.035, S≤0.035 | Rm 400-520 MPa, Rp0.2 ≥235 MPa, A≥22%, quenching and tempering |
| E | C≤0.18, Mn≥0.70, P≤0.035, S≤0.035, Al≥0.015 | Rm 400-520 MPa, Rp0.2 ≥235 MPa, A≥22%, Akv≥27J at -40℃, quenching and tempering |
| AH32 | C≤0.18, Mn 0.70-1.60, Si 0.10-0.50, P≤0.030, S≤0.030, Nb 0.005-0.05, V 0.02-0.10, Ti≤0.02, Cu≤0.35, Cr≤0.20, Ni≤0.40, Mo≤0.08, N≤0.012 | Rm 440-590 MPa, Rp0.2 ≥315 MPa, A≥22%, Akv≥31J at 0℃, TMCP/normalizing |
Application scope
GL Rules Section 3 is the Germanischer Lloyd (now DNV GL) specification for marine structural steel, stipulating requirements for steel plate materials, including grades A, B, D, and E for ordinary strength and AH to FH for high strength. The specification specifies requirements for composition, tensile strength, and low-temperature impact, emphasizing good weldability and low-temperature toughness. Deliveries must be approved by the relevant classification society or system for use in ship hull structures.
Typical applications
Widely used in the hull structure, decks, and bulkheads of GL-classed container ships, bulk carriers, and tankers. The standard strength grade is used for conventional hulls, while the high strength grade is used in high-stress and weight-reduction areas. With its good weldability and low-temperature toughness, it is suitable for various ocean-going and coastal vessels and marine structures that rely primarily on welded assembly and must meet classification requirements.
