Difference between LR AH36 and LR AH62 steel plate

LR AH36 is a high-strength shipbuilding steel plate certified by Lloyd's Register (LR). The "A" grade signifies it is impact tested at 0°C, ensuring adequate toughness for general marine environments. It has a minimum yield strength of 355 MPa and tensile strength ranging from 490 to 620 MPa, with a minimum elongation of 21%. The chemical composition features carbon ≤0.18% and manganese 0.90-1.60%. This grade is widely used for hull structures, decks, and offshore platforms where an excellent balance of strength and weldability is required.

LR AH62 is an ultra-high-strength marine steel plate also certified by Lloyd's Register (LR), designed for demanding structural applications. It is impact tested at 0°C and has a minimum yield strength of 440 MPa and tensile strength ranging from 620 to 800 MPa, with a minimum elongation of 19%. The chemical composition is more complex, featuring carbon ≤0.21%, manganese 0.90-1.70%, and additional alloying elements including nickel (0.70-1.80%), chromium (0.40-1.60%), and molybdenum (≤0.70%) to achieve superior mechanical properties. This grade is delivered in normalized or quenched and tempered conditions and is used for critical components in large vessels and offshore structures requiring maximum strength-to-weight ratio.

Both LR AH36 and LR AH62 are LR-certified high-strength marine steels with impact toughness tested at 0°C, ensuring reliable performance in general marine environments. Their primary difference lies in strength level: AH36 offers a minimum yield strength of 355 MPa with tensile strength of 490-620 MPa, suitable for general high-strength hull construction, while AH62 provides a substantially higher minimum yield strength of 440 MPa with tensile strength reaching 620-800 MPa, designed for more demanding load-bearing applications requiring superior strength-to-weight ratio. Both grades feature controlled chemical composition, but AH62 requires more complex alloying and advanced processing like quenching and tempering to achieve its enhanced mechanical properties while maintaining good weldability for critical marine service. The selection between them depends on whether the project requires the balanced strength of AH36 or the superior performance of AH62 for more extreme structural demands.

Chemical Composition

Mechanical Property