What are difference between BV E420 and BV E620 steel plate？

BV E420 is a high-strength shipbuilding steel plate certified by Bureau Veritas (BV) . The "E" grade signifies it is impact tested at -40°C, with minimum impact energy of 28J (transverse) or 42J (longitudinal) . It has a minimum yield strength of 420 MPa and tensile strength ranging from 530 to 680 MPa, with minimum elongation of 18% . The chemical composition is strictly controlled with carbon ≤0.20%, manganese ≤1.70%, and silicon ≤0.55% . This grade is typically supplied in quenched and tempered (QT) or thermomechanical controlled processed (TMCP) conditions. It is widely used for hull construction, decks, and structural components of ships and offshore structures operating in cold marine environments.

BV E620 is an ultra-high-strength marine steel also certified by Bureau Veritas (BV) with impact toughness tested at -40°C, requiring minimum impact energy of 41J (transverse) or 62J (longitudinal) . 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 exclusively supplied in quenched and tempered (QT) or TMCP conditions . It is designed for the most demanding structural components in shipbuilding, ultra-deepwater offshore platforms, and Arctic-class vessels requiring maximum strength-to-weight ratio.

Both BV E420 and BV E620 are BV-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: E420 offers a minimum yield strength of 420 MPa with tensile strength of 530-680 MPa, suitable for general high-strength hull construction , 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.

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Mechanical Property