Difference between ABS DQ47 and CCS DQ47

ABS DQ47 and CCS DQ47 are both extra-high-strength quenched and tempered steel plates specifically designed for the most demanding offshore engineering and marine applications. They are certified by two major classification societies-ABS (American Bureau of Shipping) and CCS (China Classification Society)-and represent the higher strength tier within the DQ series for these organizations, offering enhanced low-temperature toughness compared to AQ grades.

ABS Grade DQ47 is certified by the American Bureau of Shipping. The designation "DQ47" indicates it is an extra-high-strength steel with a minimum yield strength of 460 MPa and a tensile strength range of 570-720 MPa . The "D" signifies the impact test temperature of -20°C, requiring minimum Charpy V-Notch impact energy that varies by thickness (typically 46J for longitudinal specimens). These plates are manufactured using advanced heat treatment processes such as quenched and tempered (QT) , thermomechanical control processing (TMCP), or TMCP + tempering to achieve their exceptional combination of strength and toughness . Typical applications include offshore drilling rigs, platforms, FPSOs, jack-up rigs, and critical marine structures operating in cold environments.

CCS Grade DQ47 (also referred to as CCSD460) is certified by the China Classification Society and serves as the direct equivalent to ABS DQ47 in the Chinese classification system . According to classification society standards, CCS DQ47 shares identical mechanical property requirements with its ABS counterpart: minimum yield strength of 460 MPa. It belongs to the same product family as AH460, DH460, EH460, and FH460 series for shipbuilding and offshore applications. Like ABS DQ47, CCS DQ47 requires Charpy impact testing at -20°C with minimum energy requirements consistent with ABS standards .

Key Differences:
The primary distinction between these two grades lies in their certifying authority and the corresponding quality control system. ABS DQ47 complies with American Bureau of Shipping rules and is recognized internationally, particularly in projects requiring ABS certification for offshore platforms and vessels destined for ABS-classed fleets. CCS DQ47 complies with China Classification Society rules and is typically specified for offshore structures built in Chinese shipyards or for projects under Chinese classification .

From a technical perspective, these steels are considered interchangeable, and major manufacturers can produce plates certified by both societies simultaneously. 

Chemical Composition

CCS DQ47 Extra high Strength Chemical Composition in Tempering and Quenching

Mechanical Property

CCS DQ47 Extra high strength property in tempering and quenching