Difference between BV D420 and BV D460 steel plate

BV D420 and BV D460 are high-strength, normalized or thermomechanically rolled structural steel plates certified by Bureau Veritas (BV). They are predominantly used in shipbuilding and offshore structures where a combination of strength, toughness, and weldability is required. The "D" designation specifically indicates that the material is intended for use in low-temperature service, with its properties, particularly impact toughness, guaranteed at temperatures as low as -20°C (or -40°C for some subgrades). The numerical suffix (420, 460) denotes the minimum yield strength in megapascals (MPa). Therefore, BV D460 offers a higher guaranteed yield strength of at least 460 MPa, compared to BV D420's 420 MPa.

Key Differences

The core difference lies in their strength grade and the associated balance of mechanical properties. BV D460 provides approximately 9.5% higher yield strength than D420. This makes D460 suitable for applications demanding greater load capacity or where weight reduction through the use of thinner sections is critical. However, achieving this higher strength in the D460 grade often involves more stringent alloying and processing. As a result, BV D420 generally exhibits superior ductility, toughness, and easier weldability compared to D460. This makes D420 a preferred choice for highly stressed components in cold environments where resistance to brittle fracture is paramount, or for complex fabrications requiring extensive forming. In summary, the choice is a trade-off: Select D460 for higher strength efficiency; choose D420 for optimal low-temperature toughness and fabricability.

Chemical Composition

Mechanical Property