Difference between ABS AQ70 and CCS AQ70

ABS AQ70 and CCS AQ70 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 AQ70 is certified by the American Bureau of Shipping. The designation "AQ70" indicates a minimum yield strength of 690 MPa (100 ksi) and a tensile strength range of 770-940 MPa (112-136 ksi). The "A" signifies the Charpy V-notch impact test temperature, which for this grade is 0°C (32°F) with minimum average energy requirements of 41J (transverse) or 62J (longitudinal) . These plates are manufactured using a quenched and tempered (QT) process to achieve their exceptional strength and toughness. Typical applications include offshore drilling rigs, platforms, shipping containers, and critical marine structures operating in harsh environments.

CCS Grade AQ70 is certified by the China Classification Society and serves as the direct equivalent to ABS AQ70 in the Chinese classification system . According to classification society standards, CCS AQ70 shares identical mechanical property requirements with its ABS counterpart: minimum yield strength of 690 MPa . It belongs to the same product family as AQ43, AQ47, AQ51, AQ56, AQ63, and AQ70 series for shipbuilding and offshore applications . Like ABS AQ70, CCS AQ70 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 AQ70 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 AQ70 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

Mechanical Property

CCS AQ70 Extra high strength property in tempering and quenching