Difference between LR AH36 and LR AH42 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, toughness, and weldability is required .

LR AH42 is an extra-high-strength marine steel plate also certified by Lloyd's Register (LR), designed for more demanding structural applications. It is impact tested at 0°C and has a minimum yield strength of 420 MPa and tensile strength ranging from 530 to 680 MPa, with a minimum elongation of 20% . The chemical composition features carbon ≤0.21%, manganese ≤1.70%, and microalloying elements such as Nb and V . This grade is designed for demanding structural components in shipbuilding and offshore platforms requiring superior strength-to-weight ratio.

Both LR AH36 and LR AH42 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 AH42 provides a higher minimum yield strength of 420 MPa with tensile strength reaching 530-680 MPa, designed for more demanding load-bearing applications requiring superior strength-to-weight ratio. Both grades feature controlled chemical composition and maintain good weldability for critical marine service, with AH42 typically requiring more precise processing to achieve its enhanced mechanical properties.

Chemical Composition

Mechanical Property