DNV OS-C401 — DNV offshore structural steel pipes
Grades
S355G2+N, S355G3+N, S355G5+M, S355G7+M, S355G10+M, S420G2+M, S460G2+M
Chemical composition and mechanical properties
| Grade | Chemical composition | Mechanical properties |
|---|---|---|
| S355G2+N | Same as S355G2: C≤0.20, Si 0.15-0.50, Mn 0.90-1.65, P≤0.030, S≤0.030, Nb≤0.060, V 0.05-0.15, Mo≤0.30, Cu≤0.35, Ni≤0.50, Cr≤0.30, Al≥0.020, N≤0.015 | Rm 470-630 MPa, Rp0.2 ≥340 MPa, A≥22%, Akv≥50J at -40℃, normalized rolling |
| S355G3+N | Same as S355G3: C≤0.18, Si 0.15-0.50, Mn 0.90-1.65, P≤0.025, S≤0.020, Nb≤0.060, V 0.05-0.15, Mo≤0.30 | Rm 470-630 MPa, Rp0.2 ≥340 MPa, A≥22%, Akv≥50J at -40℃, normalizing |
| S355G5+M | Same as S355G5: C≤0.16, Si 0.15-0.50, Mn 1.00-1.65, P≤0.020, S≤0.015, Nb≤0.060, V 0.05-0.15, Mo≤0.30, Cu≤0.35, Ni 0.30-0.50, Cr≤0.30, Al≥0.020 | Rm 470-630 MPa, Rp0.2 ≥340 MPa, A≥22%, -40℃ Akv≥50J, TMCP |
Application scope
DNV OS-C401 is a specification for steel pipes used in offshore structures by Det Norske Veritas (DNV), with grades including S355, S420, S460, and delivery conditions such as normalized (+N) or TMCP (+M). The specification stipulates requirements for composition, tensile strength, and low-temperature impact resistance, emphasizing excellent low-temperature toughness and weldability. Approved by the relevant classification society or system, it is suitable for load-bearing steel pipes such as jackets and legs for offshore platforms.
Typical applications
Widely used in load-bearing steel pipe structures such as jackets, legs, joint pipes, and offshore wind turbine foundation piles for offshore platforms. Grades are classified according to strength and delivery condition, allowing selection based on stress, wall thickness, and marine environment. With excellent low-temperature impact toughness and good weldability, it is suitable for stationary marine engineering steel pipe structures subjected to long-term wind, waves, cyclic loads, and low-temperature seawater environments.
