What are difference between LR EH50 and LR EH55 steel plate？

LR EH50 is an extra-high-strength marine steel plate certified by Lloyd's Register (LR) . The "E" grade signifies it is impact tested at -40°C, ensuring excellent toughness for vessels operating in cold environments . It has a minimum yield strength of 500 MPa and tensile strength ranging from 610 to 770 MPa, with a minimum elongation of 18% for thicknesses up to 100mm . Impact energy requirements are 33J (transverse) and 50J (longitudinal) at -40°C . The chemical composition is strictly controlled with carbon ≤0.20% and manganese ≤1.70% .

LR EH55 is an ultra-high-strength marine steel plate also certified by Lloyd's Register (LR), with impact toughness tested at -40°C . The "55" denotes a minimum yield strength of 550 MPa and tensile strength ranging from 670 to 830 MPa, with a minimum elongation of 18% . Impact energy requirements are 37J (transverse) and 55J (longitudinal) at -40°C . Its chemical composition is similar to EH50, but typically requires more refined processing to achieve higher strength while maintaining toughness.

Both LR EH50 and LR EH55 are LR-certified extra-high-strength marine steels with excellent low-temperature toughness tested at -40°C, ensuring reliable performance in harsh marine environments. 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, while EH55 provides a higher minimum yield strength of 550 MPa with tensile strength reaching 670-830 MPa, designed for more demanding load-bearing applications . Both grades feature controlled chemical composition with carbon ≤0.20% and maintain good weldability for critical marine service, though EH55 may require more precise welding procedures due to its higher strength.

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