Difference between ABS EQ47 and ABS EQ51 steel plate

ABS EQ47 is an extra-high-strength marine steel plate certified by the American Bureau of Shipping (ABS) . The "E" designation signifies it is impact tested at -40°C, ensuring excellent low-temperature toughness for demanding marine environments . It has a minimum yield strength of 460 MPa and tensile strength ranging from 570 to 720 MPa, with minimum elongation of 17% . The chemical composition is strictly controlled with carbon ≤0.20% and manganese ≤1.70% . This grade is produced through thermo-mechanical control processing (TMCP) and is widely used in offshore drilling platforms, shipbuilding, and critical marine structures .

ABS EQ51 is an ultra-high-strength marine steel plate also certified by ABS with impact toughness tested at -40°C . The "51" denotes a minimum yield strength of 500 MPa and tensile strength ranging from 610 to 770 MPa, with minimum elongation of 16% . Impact energy requirements are minimum 33J (transverse) or 50J (longitudinal) at -40°C . The chemical composition features carbon ≤0.20% and manganese ≤1.70% . This grade is typically produced using quenching and tempering (Q&T) processes and is designed for the most demanding offshore structures and marine applications .

Both ABS EQ47 and ABS EQ51 are ABS-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: EQ47 offers a minimum yield strength of 460 MPa with tensile strength of 570-720 MPa, suitable for high-strength offshore platforms and shipbuilding , while EQ51 provides a higher minimum yield strength of 500 MPa with tensile strength reaching 610-770 MPa, designed for more demanding load-bearing applications requiring superior strength. Both grades feature controlled chemical composition and maintain good weldability for critical marine structural applications, with EQ51 typically requiring more advanced processing like quenching and tempering to achieve its enhanced mechanical properties.

Chemical Composition

Mechanical Property