Difference between DNV E550 and DNV E620 steel plate

DNV E550 is an extra-high-strength marine steel certified by DNV, with the "E" indicating impact toughness tested at -40°C . The number "550" denotes its minimum yield strength of 550 MPa . It has a tensile strength ranging from 670 to 830 MPa and minimum elongation of 16% . This grade requires advanced processing such as quenching and tempering (QT) or thermomechanical controlled processing (TMCP) to achieve its mechanical properties . It is widely used for demanding structural components in ships, offshore platforms, and marine equipment requiring superior strength and toughness.

DNV E620 is an even higher-strength marine steel also certified by DNV with impact testing at -40°C. The "620" specifies a minimum yield strength of 620 MPa . It has a higher tensile strength of 700 to 880 MPa and minimum elongation of approximately 14-15%. Like E550, it is typically supplied in quenched and tempered (QT) or TMCP conditions to achieve its superior properties . It is designed for the most critical load-bearing applications in advanced shipbuilding and offshore structures, including oil rigs and marine equipment in harsh environments.

Both DNV E550 and DNV E620 are DNV-certified extra-high-strength marine steels with excellent low-temperature toughness tested at -40°C, ensuring reliability in harsh marine conditions . Their primary difference lies in strength level: E550 offers a minimum yield strength of 550 MPa and tensile strength of 670-830 MPa, while E620 provides a substantially higher minimum yield strength of 620 MPa with tensile strength reaching 700-880 MPa . Both grades require advanced processing like QT or TMCP, but E620 demands even more stringent manufacturing controls to deliver its superior strength while maintaining adequate toughness for critical marine applications.

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Mechanical Property