What are 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 an extra-high-strength grade impact tested at -40°C, ensuring excellent toughness for vessels operating in extreme cold environments such as Arctic waters . It has a minimum yield strength of 390 MPa and tensile strength ranging from 510 to 650 MPa, with minimum elongation of 20% for thicknesses up to 100mm . The chemical composition features carbon ≤0.18% and manganese 0.90-1.60% . This grade is widely used for critical hull structures, offshore platforms, and marine components requiring good weldability and low-temperature performance .

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 and tensile strength ranging from 610 to 770 MPa, with minimum elongation of 18% for thicknesses up to 100mm . Impact energy requirements are minimum 50J (longitudinal) or 33J (transverse) at -40°C . The chemical composition features carbon ≤0.20%, manganese ≤1.70%, with microalloying elements such as Nb and V . This grade is designed for more demanding structural applications in shipbuilding and offshore platforms requiring superior strength .

Both LR EH40 and LR EH50 are LR-certified extra-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 and maintain good weldability for critical marine service.

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Mechanical Property