Plain carbon and mild steel are the most common grades of steel for shipbuilding, as they boast a raft of beneficial properties that make them uniquely suited for marine engineering. These include: High yield strengths and typical tensile strengths on a range of 490 – 620 MPa.
Steel for shipbuilding must first be classified according to one or more of the relevant classification societies: American Bureau of Shipping (ABS), Lloyd’s Register, or Det Norske Veritas (DNV). These have established globally-accepted standards and rules that steel for shipbuilding must follow, from chemical composition to downstream plate thickness.
| LR/AH36 high Strength Chemical Composition | |||||||
| Grade | The Element Max (%) | ||||||
| C | Si | Mn | P | S | Al | N | |
| LR/AH36 | 0.18 | 0.05 | 0.9-1.6 | 0.035 | 0.035 | 0.015 | |
| Nb | V | Ti | Cu | Cr | Ni | Mo | |
| 0.02-0.05 | 0.03-0.10 | 0.02 | 0.35 | 0.20 | 0.40 | 0.08 | |
Crack Sensitivity: Pcm = (C+Si/30+Mn/20+Cu/20+Ni/60+Cr/20+Mo/15+V/10+5B)%
Carbon Equivalent: Ceq = 【C+Mn/6+(Cr+Mo+V)/5+(Ni+Cu)/15】%
| LR/AH36 high strength property | |||||||
| Grade | Mechanical Property | Charpy V Impact Test | |||||
| Thickness | Yield | Tensile | Elongation | Degree | Energy 1 | Energy 2 | |
| LR/AH36 | mm | Min Mpa | Mpa | Min % | 0 | J | J |
| t≤50 | 355 | 490-630 | 21% | 24 | 34 | ||
| 50＜t≤70 | 355 | 490-630 | 21% | 27 | 41 | ||
| 70＜t≤100 | 355 | 490-630 | 21% | 34 | 50 | ||
| Note: Energy 1 is transverse impact test, Energy 2 is longitudinal | |||||||
| Equivalent steel grade of LR/AH36 | |||||||
| DNV | GL | ABS | BV | CCS | NK | KR | RINA |
| NV A36 | GL-A36 | AB/AH36 | BV/AH36 | CCS/A36 | K A36 | R A36 |
RI/A36 |
