Aluminum alloy used in the shipbuilding industry has a history of nearly a century, with the domestic and international shipbuilding industry development by leaps and bounds, lightweight is more and more attention of the vessel, as a result of the aluminum low density, high strength, high rigidity and resistance to corrosion, ship designers use aluminum ships constructed and compared using steel or other synthetic materials of ship under construction a 15-20% reduction in weight. The high toughness, corrosion resistance and weldability of aluminum alloy provide a good choice for building ship models with strict weight requirements. Since the processing cost of aluminum is low, it is more economical to use aluminum to make ships. Aluminum alloy can be used as sheet, extrusion processing and casting processing. In addition, the outstanding physical properties of aluminum alloy make it very economical to build ships with aluminum alloy. From the perspective of ship designer, ships made of aluminum alloy can achieve higher speed and longer service life. These advantages of aluminum alloy make it develop rapidly in the application of ships. Shipbuilding industry provides a broad application market for aluminum.
Marine aluminum alloy according to manufacturing process can be divided into different deformation aluminum alloy and casting aluminum alloy, because of the Marine aluminum alloy for strength, corrosion resistance, weldability, etc have special requirements, so the Marine aluminum alloy with aluminum – magnesium alloy, aluminum – magnesium – silicon alloy and aluminum and zinc, magnesium alloy, including aluminum – magnesium alloy in the most widely used on ships, according to the company’s products production situation, the following main to do focus on Marine deformation aluminum alloy.
3.1 properties, USES and chemical composition of Marine aluminum alloys
Ship with aluminum alloy can be divided into the hull structure according to the use with aluminum alloy, outfitting with aluminum alloy, ship shell structure with aluminum alloy is mainly on the 5083, 5086 and 5456 of the three alloy, 6000 series alloys due to intergranular corrosion will happen in seawater, so it is mainly used for the upper structure of the ship, for aluminum alloy main outfitting is extruded section, 7000 is the strength of the alloy after heat treatment and process performance more than 5000 series alloys is superior, the wide prospect of application in shipbuilding, the upper structure is mainly used for naval vessels, such as extrusion structure, plates, etc., However, the disadvantages of 7000 alloy are poor resistance to stress corrosion, which limits the range of the alloy.