Difference between ABS EQ47 and CCS EQ47 steel plate

ABS EQ47 and CCS EQ47 are both extra-high-strength quenched and tempered steel plates specifically engineered for the most demanding marine and offshore applications, particularly those requiring excellent toughness at low temperatures. They are certified by two major classification societies-ABS (American Bureau of Shipping) and CCS (China Classification Society)-and represent the "E" toughness tier within the 47 kgf/mm² strength class.

ABS Grade EQ47 is certified by the American Bureau of Shipping. The designation "EQ47" indicates a minimum yield strength of 460 MPa (67 ksi) and a tensile strength range of 570-720 MPa (83-104 ksi) . The "E" signifies the Charpy V-notch impact test temperature of -40°C (-40°F) , requiring minimum average energy of 46J (longitudinal) or 31J (transverse) . These plates are manufactured using either quenched and tempered (QT) or thermo-mechanical control processing (TMCP) to achieve their exceptional combination of strength and toughness, with microstructures consisting of acicular ferrite and refined granular bainite. Typical applications include offshore drilling platforms, ship hulls, icebreaker vessels, and critical marine structures operating in Arctic conditions.

CCS Grade EQ47 is certified by the China Classification Society and serves as the direct equivalent to ABS EQ47 in the Chinese classification system . According to classification society standards, CCS EQ47 shares identical mechanical property requirements with its ABS counterpart: minimum yield strength of 460 MPa and tensile strength of 570-720 MPa . It belongs to the same product family as AQ47, DQ47, EQ47, and FQ47 series for shipbuilding and offshore applications, with each letter representing a different impact test temperature . Like ABS EQ47, CCS EQ47 requires Charpy impact testing at -40°C with minimum 47J energy, and for Arctic service conditions can achieve guaranteed -60°C toughness.

Key Differences:
The primary distinction between these two grades lies in their certifying authority and the corresponding quality control system . ABS EQ47 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 EQ47 complies with China Classification Society rules and is typically specified for offshore structures built in Chinese shipyards or for projects under Chinese classification . Notable large-scale projects like deepwater semi-submersible drilling platforms have utilized both ABS and CCS certified EQ47 steel simultaneously.

From a technical perspective, these steels are considered interchangeable, and major manufacturers can produce plates certified by both societies simultaneously . The choice between them is typically determined by the flag state of the vessel, shipyard preferences, or specific project requirements. Both grades must be supplied with mill test certificates (MTC) bearing classification society surveyor signatures and can be produced with various delivery conditions including quenched and tempered, TMCP, or normalized depending on thickness requirements.

Chemical Composition

CCS EQ47 Extra high Strength Chemical Composition in Tempering and Quenching

Mechanical Property