Difference between ABS DQ47 and ABS DQ70 steel plate

ABS DQ47 is an extra-high-strength marine steel plate certified by the American Bureau of Shipping (ABS) , designed for critical offshore and shipbuilding applications . The "DQ" designation signifies it is quenched and tempered (Q&T) , with impact toughness tested at -20°C . 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 -20°C . This grade offers excellent corrosion resistance and weldability, and is widely used in offshore drilling platforms, FPSOs, and marine equipment operating in harsh environments.

ABS DQ70 is an ultra-high-strength marine steel plate also certified by ABS, produced through quenching and tempering . 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 -20°C, with minimum energy requirements of 62J (longitudinal) or 41J (transverse) . The chemical composition features carbon ≤0.20% and manganese ≤1.70%, with microalloying elements . This grade is designed for the most demanding structural components, including offshore drilling rigs, platforms, and critical marine structures requiring maximum strength-to-weight ratio.

Both ABS DQ47 and ABS DQ70 are ABS-certified, quenched and tempered ultra-high-strength marine steels with impact toughness tested at -20°C, ensuring reliable performance in harsh marine environments . Their primary difference lies in strength level: DQ47 offers a minimum yield strength of 460 MPa with tensile strength of 570-720 MPa, suitable for high-strength offshore structures , while DQ70 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 weight reduction. Both grades feature controlled chemical composition and maintain good weldability for critical marine service.

Chemical Composition

Mechanical Property