Difference between ABS DQ47 and ABS DQ56 steel plate

ABS DQ47 is an extra-high-strength marine steel plate certified by the American Bureau of Shipping (ABS) , produced through quenching and tempering (Q&T) . The "DQ" designation signifies it is impact 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 toughness and weldability, and is widely used in shipbuilding, offshore drilling platforms, and marine structures.

ABS DQ56 is an ultra-high-strength marine steel plate also certified by ABS, produced through quenching and tempering (Q&T) . The "56" denotes a minimum yield strength of 550 MPa and tensile strength ranging from 670 to 835 MPa, with minimum elongation of 16% . Impact testing is performed at -20°C, with minimum energy requirements of 55J (longitudinal) or 37J (transverse) . The chemical composition features nickel content of 8.0-9.5% for enhanced low-temperature performance . This grade is designed for critical offshore structures, including jack-up rigs and platforms in harsh environments.

Both ABS DQ47 and ABS DQ56 are ABS-certified, quenched and tempered ultra-high-strength marine steels with excellent toughness for demanding offshore applications . Their primary differences lie in strength and alloy content: DQ47 offers a minimum yield strength of 460 MPa with tensile strength of 570-720 MPa, suitable for high-strength shipbuilding and offshore platforms , while DQ56 provides a higher minimum yield strength of 550 MPa with tensile strength reaching 670-835 MPa, enhanced by significant nickel content (8.0-9.5%) for superior low-temperature performance in the most demanding offshore structures . Both grades maintain good weldability and are essential for critical marine structural applications.

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