Difference between LR DH40 and LR DH46 steel plate

LR DH40 is a high-strength shipbuilding steel plate certified by Lloyd's Register (LR) . The "D" grade signifies it is impact tested at -20°C . It has a minimum yield strength of 390 MPa and tensile strength ranging from 510 to 660 MPa . The chemical composition is strictly controlled with carbon ≤0.18-0.20% and manganese 0.90-1.60% . Minimum elongation is 20%. This grade is typically supplied in normalized, quenched and tempered, or TMCP conditions . It is widely used for hull construction and offshore platforms.

LR DH46 is an extra-high-strength marine steel also certified by Lloyd's Register (LR) with impact toughness tested at -20°C . The "46" denotes a minimum yield strength of 460 MPa . It has a tensile strength ranging from 570 to 720 MPa and minimum elongation of 19% . Impact energy requirements are minimum 46J (longitudinal) or 31J (transverse) at -20°C. The chemical composition features carbon ≤0.20% and manganese ≤1.70%, with microalloying elements . This grade is typically supplied in normalized or controlled rolled conditions . It is designed for demanding structural components in shipbuilding and offshore structures.

Both LR DH40 and LR DH46 are LR-certified high-strength marine steels with impact toughness tested at -20°C, ensuring reliable performance in cold marine environments . Their primary difference lies in strength level: DH40 offers a minimum yield strength of 390 MPa with tensile strength of 510-660 MPa, suitable for general high-strength hull construction , while DH46 provides a higher minimum yield strength of 460 MPa with tensile strength reaching 570-720 MPa, designed for more demanding load-bearing applications requiring superior strength. Both grades feature controlled chemical composition with carbon ≤0.18-0.20% and manganese ≤1.60-1.70%, and maintain good weldability for marine service.

Chemical Composition

Mechanical Property