Difference between ABS EQ47 and ABS EQ70 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% . Impact energy requirements are minimum 46J (longitudinal) or 31J (transverse) at -40°C . This grade is typically produced through thermo-mechanical controlled processing (TMCP) or quenching and tempering . It is widely used in offshore drilling platforms, shipbuilding, and critical marine structures .

ABS EQ70 is an ultra-high-strength marine steel plate also certified by ABS, produced through quenching and tempering (Q&T) . The "70" denotes a minimum yield strength of 690 MPa and tensile strength ranging from 770 to 940 MPa, with minimum elongation of 14% . Impact testing is performed at -40°C, with minimum energy requirements of 62J (longitudinal) or 41J (transverse) . The chemical composition is strictly controlled with carbon ≤0.20% and manganese ≤1.70% . This grade is designed for the most demanding offshore structures, including drilling platforms, jack-up rigs, and critical marine engineering projects requiring maximum strength-to-weight ratio .

Both ABS EQ47 and ABS EQ70 are ABS-certified 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 EQ70 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 . Additionally, EQ47 can be produced using TMCP or QT processes , whereas EQ70 requires more advanced processing like quenching and tempering (Q&T) to achieve its enhanced mechanical properties. Both grades feature controlled chemical composition and maintain good weldability for critical marine structural applications.

Chemical Composition

Mechanical Property