Difference between BV E550 and BV E690 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 silicon ≤0.55% . Impact energy requirements are 37J (transverse) or 55J (longitudinal) at -40°C . This grade is typically supplied in quenched and tempered (QT) or thermomechanical controlled processed (TMCP) conditions . It is widely used for demanding structural components in shipbuilding, offshore platforms, and marine structures .

BV E690 is an ultra-high-strength marine steel also certified by Bureau Veritas (BV) with impact toughness tested at -40°C . The "690" denotes a minimum yield strength of 690 MPa . It has a tensile strength ranging from 770 to 940 MPa and minimum elongation of 14% . The chemical composition features carbon ≤0.20%, manganese ≤1.70%, with microalloying elements including Cr, Ni, Mo, and Cu for enhanced properties . Impact energy requirements are 46J (transverse) or 69J (longitudinal) at -40°C . 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 E550 and BV E690 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 E690 provides a substantially higher minimum yield strength of 690 MPa with tensile strength reaching 770-940 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