Difference between LR EH40 and LR EH50 steel plate

LR EH40 is a high-strength shipbuilding steel plate certified by Lloyd's Register (LR) . The "EH" designation signifies it is impact tested at -40°C, ensuring excellent toughness for cold-environment applications such as Arctic operations . It has a minimum yield strength of 390 MPa and tensile strength ranging from 510 to 650 MPa, with minimum elongation of 20% . The chemical composition is strictly controlled with carbon ≤0.18% and manganese 0.90-1.60% . Impact energy requirements are minimum 39J (transverse) or 59J (longitudinal) at -40°C for thicknesses up to 50mm. This grade is widely used for hull construction, offshore platforms, and critical marine structures .

LR EH50 is an extra-high-strength marine steel plate also certified by Lloyd's Register (LR) with impact toughness tested at -40°C . The "50" denotes a minimum yield strength of 500 MPa . It has a higher tensile strength ranging from 610 to 770 MPa and minimum elongation of 18% . The chemical composition features carbon ≤0.20%, manganese ≤1.70%, with microalloying elements including Nb, V, and Ti . Impact energy requirements are minimum 33J (transverse) or 50J (longitudinal) at -40°C for thicknesses up to 50mm . This grade is designed for demanding structural components in shipbuilding, offshore platforms, and marine equipment requiring superior strength-to-weight ratio.

Both LR EH40 and LR EH50 are LR-certified 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: EH40 offers a minimum yield strength of 390 MPa with tensile strength of 510-650 MPa, suitable for general high-strength hull construction and offshore structures , while EH50 provides a substantially higher minimum yield strength of 500 MPa with tensile strength reaching 610-770 MPa, designed for more demanding load-bearing applications requiring superior strength. Both grades feature controlled chemical composition with carbon ≤0.18-0.20% and require advanced processing like TMCP or QT to achieve their mechanical properties while maintaining good weldability for critical marine service.

Chemical Composition

Mechanical Property