Difference between ABS AQ63 and CCS AQ63 steel plate

ABS AQ63 and CCS AQ63 are both extra-high-strength quenched and tempered steel plates specifically designed for the most demanding marine and offshore engineering applications . They are certified by two major classification societies-ABS (American Bureau of Shipping) and CCS (China Classification Society)-and represent the highest tier of yield strength within the AQ series for these organizations.

ABS Grade AQ63 is certified by the American Bureau of Shipping. The designation "AQ63" indicates a minimum yield strength of 90 ksi (approximately 620 MPa) and a tensile strength range of 104-129 ksi (720-890 MPa) . The "A" signifies the Charpy V-notch impact test temperature, which for this grade is typically 0°C (32°F) with minimum average energy requirements of 41J (transverse) or 62J (longitudinal) . However, some suppliers indicate that ABS AQ63 can demonstrate excellent low-temperature toughness with impact testing at -60°C for specific applications . These plates are manufactured using a quenched and tempered (QT) process to achieve their exceptional strength and toughness . Typical applications include mobile offshore drilling units, shipbuilding, and critical marine structures.

CCS Grade AQ63 is certified by the China Classification Society and serves as the direct equivalent to ABS AQ63 in the Chinese classification system . According to classification society standards and product catalogs from major steel manufacturers, CCS AQ63 shares identical mechanical property requirements with its ABS counterpart: minimum yield strength of 620 MPa and belongs to the same product family as AQ43, AQ47, AQ51, AQ56, AQ63, and AQ70 series for shipbuilding and offshore applications . Like ABS AQ63, CCS AQ63 requires Charpy impact testing with the "A" grade indicating 0°C test temperature.

Key Differences:
The primary distinction between these two grades lies in their certifying authority and the corresponding quality control system . ABS AQ63 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 AQ63 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 AQ63 Extra high Strength Chemical Composition in Tempering and Quenching

Mechanical Property

CCS AQ63 Extra high strength property in tempering and quenching