Difference between RINA D500 and RINA D620 steel plate

RINA D500 is an extra-high-strength marine steel plate certified by the Italian classification society RINA (Registro Italiano Navale) for shipbuilding and offshore applications. The "D" grade signifies it is impact tested at -20°C, with a minimum impact energy of 33J (longitudinal) . It has a minimum yield strength of 500 MPa and tensile strength ranging from 610 to 770 MPa, with a minimum elongation of 16% . The chemical composition is strictly controlled with carbon ≤0.20% and manganese ≤1.70%, and includes elements such as nickel and copper to enhance corrosion resistance in marine environments . This grade is available in thicknesses up to 260mm and is typically supplied in thermomechanical rolled (TMCP) or quenched and tempered (QT) conditions . It is widely used for offshore drilling platforms, hull structures, and FPSO vessels .

RINA D620 is an ultra-high-strength marine steel plate also certified by RINA, with impact toughness tested at -20°C requiring a minimum of 41J (longitudinal) . The "620" denotes a minimum yield strength of 620 MPa and tensile strength ranging from 720 to 890 MPa, with a minimum elongation of 15% . The chemical composition features carbon ≤0.20% and manganese ≤1.70%, with microalloying elements such as Nb, V, Ti, Cr, Ni, and Mo for enhanced properties . This grade requires advanced processing and is typically supplied in quenched and tempered (QT) or TMCP conditions . It is designed for the most demanding structural components in shipbuilding, ultra-deepwater offshore platforms, Arctic-class vessels, and FPSO units requiring maximum strength-to-weight ratio .

Both RINA D500 and RINA D620 are RINA-certified extra-high-strength marine steels with excellent low-temperature toughness tested at -20°C, ensuring reliable performance in harsh marine environments . Their primary difference lies in strength level: D500 offers a minimum yield strength of 500 MPa with tensile strength of 610-770 MPa, suitable for high-strength offshore platforms and general shipbuilding , while D620 provides a substantially higher minimum yield strength of 620 MPa with tensile strength reaching 720-890 MPa, designed for the most demanding load-bearing applications requiring maximum strength-to-weight ratio . Both grades feature strictly controlled chemical composition with carbon ≤0.20% and maintain good weldability for critical marine service, though D620 requires more complex alloying and advanced processing like QT or TMCP to achieve its superior mechanical properties . The selection between them depends on whether the project requires the balanced strength of D500 or the enhanced performance of D620 for more extreme structural demands.

RINA D500 extra high Strength Chemical Composition in Tempering and Quenching

RINA D620 extra high Strength Chemical Composition in Tempering and Quenching

RINA D500 extra high strength property in Tempering and Quenching

RINA D620 extra high strength property in Tempering and Quenching