Shipbuilding steel generally refers to steel for hull structures, which refers to steel used to manufacture hull structures produced in accordance with the requirements of classification society construction specifications. It is often ordered, scheduled and sold as special steel. One ship includes ship plates, shaped steel, etc.
At present, several major steel companies in my country have production, and can produce marine steel products according to user needs in different countries, such as the United States, Norway, Japan, Germany, France, etc. The specifications are as follows:
| Country | Standard | Country | Standard |
| United States | ABS | China | CCS |
| Germany | GL | Norway | DNV |
| France | BV | Japan | KDK |
| UK | LR |
(1) Variety specifications
Structural steel for hulls is divided into strength levels according to their minimum yield point: general strength structural steel and high strength structural steel.
The general strength structural steel specified by China Classification Society is divided into four quality levels: A, B, D, and E; the high-strength structural steel specified by China Classification Society is divided into three strength levels and four quality levels:
| A32 | A36 | A40 |
| D32 | D36 | D40 |
| E32 | E36 | E40 |
| F32 | F36 | F40 |
(2) Mechanical properties and chemical composition
Mechanical properties and chemical composition of general strength hull structural steel
| Steel Grade | Yield Pointσs(MPa) Min | Tensile Strengthσb(MPa) | Elongationσ%Min | 碳C | 锰Mn | 硅Si | 硫S | 磷P |
| A | 235 | 400-520 | 22 | ≤0.21 | ≥2.5 | ≤0.5 | ≤0.035 | ≤0.035 |
| B | ≤0.21 | ≥0.80 | ≤0.35 | |||||
| D | ≤0.21 | ≥0.60 | ≤0.35 | |||||
| E | ≤0.18 | ≥0.70 | ≤0.35 |
Mechanical properties and chemical composition of high-strength hull structural steel
| Steel Grade | Yield Pointσs(MPa) Min | Tensile Strengthσb(MPa) | Elongationσ%Min | 碳C | 锰Mn | 硅Si | 硫S | 磷P |
| A32 | 315 | 440-570 | 22 | ≤0.18 | ≥0.9-1.60 | ≤0.50 | ≤0.035 | ≤0.035 |
| D32 | ||||||||
| E32 | ||||||||
| F32 | ≤0.16 | ≤0.025 | ≤0.025 | |||||
| A36 | 355 | 490-630 | 21 | ≤0.18 | ≤0.035 | ≤0.035 | ||
| D36 | ||||||||
| E36 | ||||||||
| F36 | ≤0.16 | ≤0.025 | ≤0.025 | |||||
| A40 | 390 | 510-660 | 20 | ≤0.18 | ≤0.035 | ≤0.035 | ||
| D40 | ||||||||
| E40 | ||||||||
| F40 | ≤0.16 | ≤0.025 | ≤0.025 |
(3) Precautions for delivery and acceptance of marine steel products:
1. Review of quality certificate:
The steel factory must deliver the goods according to the user’s requirements and the specifications agreed in the contract and provide the original quality certificate. The certificate must contain the following contents:
(1) Specification requirements;
(2) Quality record number and certificate number;
(3) Furnace batch number, technical level;
(4) Chemical composition and mechanical properties;
(5) Certificate of approval from the classification society and signature of the surveyor.
2. Physical review:
For delivery of marine steel, the physical object should have the manufacturer’s logo, etc. Specifically:
(1) Classification society approval mark;
(2) Use paint to frame or paste the mark, including technical parameters such as: furnace batch number, specification standard grade, length and width dimensions, etc.;
(3) The appearance is smooth and smooth, without defects.
Post time: Mar-16-2024