Difference between BV D460 and BV D550

BV D460 and BV D550 are high-strength structural steel plates classified by Bureau Veritas (BV) for marine and offshore applications. These grades are commonly used in critical areas of shipbuilding, such as hull girders, offshore modules, and other heavy-duty structures where a balance of strength, weldability, and toughness is essential.

Key Differences:

The core difference is their specified minimum yield strength. BV D460 offers a yield strength of 460 MPa, while BV D550 provides a significantly higher yield strength of 550 MPa. This makes D550 capable of withstanding greater loads, allowing for weight reduction through the use of thinner plate sections in designed structures.

To achieve its superior strength, D550 typically requires a more refined chemical composition and is often supplied in a quenched and tempered (Q&T) condition. In contrast, D460 can often be supplied in a normalized or thermo-mechanically controlled processed (TMCP) state. As a result, D550 generally presents greater challenges in fabrication, particularly in welding. It demands stricter control of preheating, heat input, and post-weld heat treatment to preserve its mechanical properties and avoid cracking. Therefore, the selection between D460 and D550 involves a trade-off: D550 offers higher strength and weight savings, while D460 provides easier fabrication and often better cost-effectiveness for many applications.

Chemical Composition

Mechanical Property