Difference between LR EH50 and LR EH69 steel plate

LR EH50 is an extra-high-strength marine steel plate certified by Lloyd's Register (LR) . The "EH" designation signifies it is an extra-high-strength grade with impact toughness tested at -40°C, ensuring excellent performance in harsh environments like Arctic waters . 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 features carbon ≤0.20%, manganese ≤1.70%, and microalloying elements such as Nb and V . This grade is typically supplied in TMCP or normalized conditions and is widely used for critical hull structures and offshore platforms .

LR EH69 is an ultra-high-strength marine steel plate also certified by Lloyd's Register (LR) with impact toughness tested at -40°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% for thicknesses up to 100mm . Impact energy requirements are minimum 69J (longitudinal) or 46J (transverse) at -40°C . The chemical composition is strictly controlled with carbon ≤0.20% and manganese ≤1.70%, featuring microalloying elements including Nb, V, Ti, and often Ni . This grade is designed for the most demanding structural components in ultra-large container vessels, heavy-lift ships, and Arctic-class offshore units requiring maximum strength-to-weight ratio.

Both LR EH50 and LR EH69 are LR-certified ultra-high-strength marine steels with excellent low-temperature toughness tested at -40°C, ensuring reliable performance in harsh marine environments including Arctic conditions . Their primary difference lies in strength level: EH50 offers a minimum yield strength of 500 MPa with tensile strength of 610-770 MPa, suitable for high-strength hull construction and demanding offshore structures , while EH69 provides a substantially higher minimum yield strength of 690 MPa with tensile strength reaching 770-940 MPa, designed for the most critical load-bearing applications requiring maximum weight reduction. Both grades feature controlled chemical composition, but EH69 requires more advanced processing like quenching and tempering (Q&T) to achieve its superior mechanical properties while maintaining good weldability for critical marine service.

Chemical Composition

Mechanical Property