Difference between BV DH32 and BV DH40 steel plate

BV DH32 is a high-strength shipbuilding steel plate certified by Bureau Veritas (BV) . The "D" grade signifies it is impact tested at -20°C, making it suitable for vessels operating in cold environments such as the North Atlantic in winter . The "32" denotes a minimum yield strength of 315 MPa (32 ksi) . It has a tensile strength ranging from 440 to 590 MPa and minimum elongation of 22% . The chemical composition features carbon ≤0.18%, manganese 0.90-1.60%, and microalloying elements for grain refinement . This grade is typically supplied in normalized or thermomechanical controlled processed (TMCP) conditions . It is widely used for hull structures, decks, and critical components requiring reliable low-temperature performance.

BV DH40 is a higher-strength marine steel also certified by Bureau Veritas (BV) with impact toughness tested at -20°C . The "40" denotes a minimum yield strength of 390 MPa . It has a tensile strength ranging from 510 to 660 MPa and minimum elongation of 20% . The chemical composition includes carbon ≤0.18%, manganese 0.90-1.60%, with strict control of phosphorus and sulfur . This grade requires advanced processing and is typically supplied in quenched and tempered (QT) or TMCP conditions . It is designed for demanding structural components such as sheer strake, deck plating, and bilge strake on vessels operating in sub-zero temperatures.

Both BV DH32 and BV DH40 are BV-certified high-strength marine steels with impact toughness tested at -20°C, ensuring reliable performance in cold marine environments . Their primary difference lies in strength level: DH32 offers a minimum yield strength of 315 MPa with tensile strength of 440-590 MPa, suitable for general high-strength hull construction in cold climates , while DH40 provides a higher minimum yield strength of 390 MPa with tensile strength reaching 510-660 MPa, designed for more demanding load-bearing applications and critical structural components on vessels operating in sub-zero temperatures. Both grades feature controlled chemical composition with carbon ≤0.18% and manganese 0.90-1.60%, and require advanced processing like TMCP or normalized rolling to achieve their mechanical properties while maintaining good weldability for marine service . The selection between them depends on the specific strength requirements of the vessel design and classification society rules.

Chemical Composition

Mechanical Property