Shipbuilding Steel Plate

General strength hull structural steel, that is, the former marine carbon steel (mild steel), divided into A, B, D, E four grades, applicable to the thickness of not more than 100mm steel plate. General strength hull structural steel four grades of steel carbon, phosphorus and sulfur content directly affects its strength, the higher the carbon content, high strength, general strength hull structural steel in the repair of small and medium-sized ships in the application of more.

High strength hull structural steel is also known as marine low alloy steel. High-strength hull structural steel according to its minimum yield strength classified strength level, each strength level and according to the different impact toughness is divided into A, D, E, F and so on 4 levels.

A32, D32, E32, F32 yield strength of not less than 315N/mm ^ 2, tensile strength of 440 ~ 570N/mm ^ 2, A, D, E, F, respectively, that their respective 0 °, -20 °, -40 °, -60 ° can be achieved under the circumstances of the impact toughness;

The yield strength of A36, D36, E36, F36 is not less than 355N/mm^2, the tensile strength is 490-620N/mm^2, and A, D, E, F indicate the impact toughness that each of them can achieve at 0°, -20°, -40°, -60° respectively;

A40, D40, E40, F40 have a yield strength of not less than 390N/mm^2 and a tensile strength of 510 to 660N/mm^2, and A, D, E, and F denote the impact toughness that each of them can achieve at 0°, -20°, -40°, and -60°, respectively.

Steel plate is the main part of the hull structure, accounting for about 60% to 65%, such as the hull plate, deck plate and compartment bulkheads, etc., the general thickness of the steel plate in the 4mm and below is called thin plate, more than 4mm is called thick plate; the size range of the marine steel plate is generally: 6 ~ 10mm thick, 1200 ~ 3000mm wide, 6000 ~ 14000mm long.

The proportion of steel section in the hull structure is second only to the steel plate, about 35% to 40%, mainly used as the hull skeleton. According to its cross-section shape can be divided into: flat steel, ball flat steel, angle steel, I-beam, T-beam and channel steel.

Ship's head and tail column, anchor, guide cable hole, bollard and tail shaft tube, etc. often use cast steel, while the ship's rudder rod, shaft and other simple shape of the components are more often used forged steel. Forged steel mechanical strength and toughness is better than cast steel, but because of the limitations of the processing technology, the structure of its components should not be too complex.