Difference between LR DH46 and LR DH69 steel plate

LR DH46 is an extra-high-strength marine steel plate certified by Lloyd's Register (LR) . The "DH" designation signifies it is a higher-strength grade with impact toughness tested at -20°C . It has a minimum yield strength of 460 MPa and tensile strength ranging from 570 to 720 MPa, with minimum elongation of 19% for thicknesses up to 100mm . Impact energy requirements at -20°C are minimum 46J (longitudinal) or 31J (transverse) . The chemical composition features carbon ≤0.20%, manganese ≤1.70%, with microalloying elements including Nb and V. This grade is typically supplied in normalized or controlled rolled conditions and is widely used for hull construction and offshore structures.

LR DH69 is an ultra-high-strength marine steel plate also certified by Lloyd's Register (LR) with impact toughness tested at -20°C . The "69" denotes a minimum yield strength of 690 MPa . It has a higher tensile strength ranging from 770 to 940 MPa and minimum elongation of 16% for thicknesses up to 100mm . Impact energy requirements at -20°C are minimum 69J (longitudinal) or 46J (transverse) . The chemical composition is similar to DH46 with carbon ≤0.20% and manganese ≤1.70%, along with microalloying elements . This grade is designed for the most demanding structural components in shipbuilding and offshore platforms requiring maximum strength-to-weight ratio.

Both LR DH46 and LR DH69 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: DH46 offers a minimum yield strength of 460 MPa with tensile strength of 570-720 MPa, suitable for general high-strength hull construction , while DH69 provides a substantially higher minimum yield strength of 690 MPa with tensile strength reaching 770-940 MPa, offering approximately 50% greater strength for the most demanding load-bearing applications requiring maximum weight reduction. Both grades feature similar controlled chemical composition with carbon ≤0.20% and require advanced processing to achieve their mechanical properties while maintaining good weldability for critical marine service.

Chemical Composition

Mechanical Property