What are difference between LR DH50 and LR DH62 steel plate？

LR DH50 is an extra-high-strength marine steel plate certified by Lloyd's Register (LR) . The "D" grade signifies it is impact tested at -20°C, with minimum impact energy of 33J (transverse) or 50J (longitudinal) . It has a minimum yield strength of 500 MPa and tensile strength ranging from 610 to 770 MPa, with minimum elongation of 18% for thicknesses up to 100mm. The chemical composition is strictly controlled with carbon ≤0.20% and manganese ≤1.70%, featuring microalloying elements like Nb and V . This grade is typically supplied in normalized or controlled rolled conditions. It is widely used for demanding structural components in shipbuilding, offshore platforms, and marine structures requiring superior strength.

LR DH62 is an ultra-high-strength marine steel plate also certified by Lloyd's Register (LR) with impact toughness tested at -20°C . The "62" denotes a minimum yield strength of 620 MPa . It has a tensile strength ranging from 720 to 890 MPa and minimum elongation of 17% for thicknesses up to 100mm . Impact energy requirements are higher, at 41J (transverse) or 62J (longitudinal) at -20°C . The chemical composition features carbon ≤0.20%, manganese ≤1.70%, with microalloying elements including Nb, V, Ti, Cu, Cr, Ni, and Mo for enhanced properties . This grade requires advanced processing and is typically supplied in quenched and tempered (QT) or TMCP conditions. It is designed for the most critically stressed structural components in shipbuilding and offshore engineering, offering an exceptional strength-to-weight ratio.

Both LR DH50 and LR DH62 are LR-certified extra-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: DH50 offers a minimum yield strength of 500 MPa with tensile strength of 610-770 MPa, suitable for high-strength offshore structures , while DH62 provides a substantially higher minimum yield strength of 620 MPa with tensile strength reaching 720-890 MPa, designed for the most demanding load-bearing applications requiring maximum strength-to-weight ratio. Both grades feature controlled chemical composition with carbon ≤0.20% and manganese ≤1.70% , and DH62 typically requires more advanced processing like QT or TMCP to achieve its superior mechanical properties while maintaining good weldability for critical marine service.

Chemical Composition

Mechanical Property