Rules of American Bureau of Shipping

The American Bureau of Shipping (ABS) is one of the world's leading classification societies and a founding member of the International Association of Classification Societies (IACS). Its "Rules for Building and Classing Steel Vessels" provide authoritative technical standards for ship design, construction, and material selection, with systematic and stringent requirements for hull structural steel plates to ensure structural safety and long-term service performance in demanding marine environments.

In terms of steel plate specifications, ABS classifies hull steel into ordinary strength grades (A, B, D, E) and higher strength grades (such as AH32, AH36, AH40, DH32, DH36, DH40, EH32, EH36, EH40), based on the importance, stress conditions, and service environment of the structural components. Each grade has clearly defined requirements for chemical composition, mechanical properties, and impact toughness. To ensure good weldability and resistance to cracking, ABS standards strictly control the carbon equivalent (Ceq) and limit harmful elements such as sulfur (S) and phosphorus (P), with even stricter limits for high-strength and low-temperature service steels.

Mechanical properties are central to ABS’s plate requirements. The rules specify yield strength, tensile strength, elongation, and Charpy V-notch impact energy (KV2) at ambient and low temperatures (e.g., 0°C, -20°C, -40°C). For vessels operating in cold or polar waters, steel plates used in critical structural areas—such as the bow, side shells, and superstructure connections—must pass impact tests at -40°C or lower to prevent brittle fracture in cold environments.

Furthermore, ABS sets detailed requirements for manufacturing processes, surface quality, dimensional tolerances, non-destructive testing (e.g., ultrasonic testing), and traceability. Steel production must be subject to inspection by ABS-authorized surveyors (WITNESS), with supervision throughout the entire process, including steelmaking, rolling, heat treatment, and testing. All plates used in primary load-bearing structures must be accompanied by complete material certification and maintain full traceability from slab to final product.

In summary, ABS ensures high reliability and safety of marine steel plates under various operating conditions through a scientific material grading system, rigorous performance verification, and comprehensive quality control, setting a high technical benchmark for the global shipbuilding and offshore industries.

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