Strength and ship type of shipbuilding steel plate

When using steel for ships, the strength levels of the steel plates are also different depending on the type of ship. The strength and ship type of shipbuilding steel plate are classified as follows:

Large oil tanker: The structure of the current large oil tanker is generally a double (layer) shell structure. Due to the double (layer) shell structure, high-strength steel is only used in the main structural part, and the proportion of its use is reduced from 70% in single-hull ships to 25%. 310-360MPa grade high-strength steel plates are mainly used on the longitudinal parts of the upper deck and the bottom of the ship.

Bulk carriers: Bulk carriers are roughly divided into three categories: 40,000-ton, 60,000-ton and 140-200,000-ton. Taking the latter large ship as an example, since the structure is an open-top structure, it is easy to generate large stress on the side of the deck, so the 390MPa grade steel plate is used on the side of the deck.

Container ships: At present, there are large cargo ships (produced by Nantong COSCO Kawasaki) that can carry 10,000 containers. Since the structure is also an upper open structure, the side of the deck is prone to large stress, so the 390-440MPa grade steel plate is used for the side of the deck.

Liquefied petroleum gas carrier (LPG ship): Since the transport is liquefied petroleum gas with a temperature of minus 40- minus 45°C, several large tanks that are independent of the hull are generally placed in the cabin. Generally, aluminum-killed steel with good low temperature toughness that is resistant to low temperature of minus 60 °C is used. In addition, the side of the hull is also made of low-temperature resistant steel on the side facing the tank to prevent accidents. Because other parts generally do not have too much longitudinal stress, general-strength steel is used.

Liquefied Natural Gas Carriers (LNG Carriers): Since they transport LNG at temperatures as low as -161°C, various measures have been taken to avoid being affected by thermal and thermal stress. There are roughly four forms of structure, but from the perspective of large structure, several independent tanks are basically placed in the hull and properly connected to the hull. The tank material is generally made of low-alloy, alloy steel and other steel plates that are resistant to extremely low temperatures. The upper deck is made of high-strength steel plate due to its large opening.

Passenger ships: As passenger ships have special requirements for stability, the upper part is made of steel plates with a thickness of 4.5-6mm. Most of them use general-strength steel plates, and some use high-strength steel plates.

The steel plates used in river boats are mainly medium plates, and a small amount of thin plates are used. Most of them use general-strength steel plates, and a small amount of high-strength plates are used.