Difference between BV E550 and BV E620 steel plate

BV E550 is an extra-high-strength marine steel plate certified by Bureau Veritas (BV) . The "E" grade signifies it is impact tested at -40°C, ensuring reliable performance in extreme cold environments such as Arctic waters . It has a minimum yield strength of 550 MPa and tensile strength ranging from 670 to 830 MPa, with minimum elongation of 16% . The chemical composition is strictly controlled with carbon ≤0.20%, manganese ≤1.70%, and microalloying elements . This grade is typically supplied in normalized, quenched and tempered (QT), or thermomechanical controlled processed (TMCP) conditions . It is widely used for demanding structural components in shipbuilding, offshore platforms, and marine equipment.

BV E620 is an ultra-high-strength marine steel also certified by Bureau Veritas (BV) with impact toughness tested at -40°C . The "620" denotes a minimum yield strength of 620 MPa . It has a tensile strength ranging from 720 to 890 MPa and minimum elongation of 15% . The chemical composition features carbon ≤0.20%, manganese ≤1.70%, with strict control of phosphorus and sulfur . This grade requires advanced processing and is typically supplied in quenched and tempered (QT) or TMCP conditions . It is designed for the most critical load-bearing applications in shipbuilding, ultra-deepwater offshore platforms, and Arctic-class vessels.

Both BV E550 and BV E620 are BV-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: E550 offers a minimum yield strength of 550 MPa with tensile strength of 670-830 MPa, suitable for high-strength offshore structures , while E620 provides a substantially higher minimum yield strength of 620 MPa with tensile strength reaching 720-890 MPa, designed for the most demanding load-bearing applications requiring maximum strength-to-weight ratio . Both grades feature controlled chemical composition with carbon ≤0.20% and manganese ≤1.70% , and require advanced processing like QT or TMCP to achieve their superior mechanical properties while maintaining good weldability for critical marine service.

Chemical Composition

Mechanical Property