ABS DQ56 steel plate vs ABS DQ70 steel plate

ABS DQ56 is an ultra-high-strength marine steel plate certified by the American Bureau of Shipping (ABS) , produced through quenching and tempering (Q&T) . The "D" grade signifies it is impact tested at -20°C (with some suppliers noting -40°C testing as well) . It has a minimum yield strength of 550 MPa and tensile strength ranging from 670 to 835 MPa, with minimum elongation of 16% . Impact energy requirements are minimum 55J (longitudinal) or 37J (transverse) at -20°C. This grade is widely used in offshore drilling platforms, shipbuilding, and critical marine structures requiring high strength and toughness.

ABS DQ70 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 -20°C, with minimum energy requirements of 62J (longitudinal) or 41J (transverse) . The chemical composition features carbon ≤0.20% and manganese ≤1.70% . This grade is designed for the most demanding offshore structures, including drilling platforms and critical marine engineering projects.

Both ABS DQ56 and ABS DQ70 are ABS-certified, quenched and tempered ultra-high-strength marine steels with excellent toughness tested at -20°C, ensuring reliable performance in harsh marine environments . Their primary difference lies in strength level: DQ56 offers a minimum yield strength of 550 MPa with tensile strength of 670-835 MPa, suitable for high-strength offshore platforms and shipbuilding, 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 strength-to-weight ratio. Both grades feature controlled chemical composition and maintain good weldability for critical marine structural applications.

Chemical Composition

Mechanical Property