LR DH62 vs LR DH69

LR DH62 is an ultra-high-strength marine steel plate certified by Lloyd's Register (LR) . The "D" grade signifies it is impact tested at -20°C, ensuring reliable toughness for cold marine environments . It has a minimum yield strength of 620 MPa and tensile strength ranging from 720 to 890 MPa, with minimum elongation of 17% . The chemical composition is strictly controlled with carbon ≤0.20% and manganese ≤1.70%, featuring microalloying elements such as Nb, V, Ti, Cu, Cr, Ni, and Mo . This grade is typically supplied in quenched and tempered (QT) or TMCP conditions and is designed for critically stressed structural components in modern shipbuilding and offshore engineering .

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 and tensile strength ranging from 770 to 940 MPa, with minimum elongation of 16% . Impact energy requirements are minimum 69J (longitudinal) or 46J (transverse) at -20°C . The chemical composition is similar to DH62 with carbon ≤0.20% and manganese ≤1.70%, along with microalloying elements . This grade requires advanced processing such as TMCP or quenching and tempering and is designed for the most demanding load-bearing applications requiring maximum strength-to-weight ratio .

Both LR DH62 and LR DH69 are LR-certified ultra-high-strength marine steels with excellent impact toughness tested at -20°C, ensuring reliable performance in cold marine environments . Their primary difference lies in strength level: DH62 offers a minimum yield strength of 620 MPa with tensile strength of 720-890 MPa, suitable for critically stressed structural components , while DH69 provides a substantially higher minimum yield strength of 690 MPa with tensile strength reaching 770-940 MPa, designed for the most demanding load-bearing applications requiring maximum weight reduction.

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Mechanical Property