Analysis of the development history and current situation of marine steel

The rapid development of the world's shipping industry has higher and higher requirements for ships, resulting in the continuous improvement of the requirements for shipbuilding materials for various large ships and special ships. Starting from the development trend of the shipbuilding industry in my country and the world's major shipbuilding countries in recent years, this paper systematically analyzes the performance requirements of various steel materials in the field of shipbuilding and ocean engineering manufacturing, and analyzes the demand for marine steel and high-performance marine steel in the future. The development prospect of steel is predicted.
Key words: shipbuilding; marine steel; high strength steel; development status

Marine steel refers to the steel used to manufacture the hull structure of sea-going ships and inland river ships, and is also the steel plate that requires the highest structural strength, usually high-quality carbon steel and high-quality low-alloy steel. Marine steel requires certain strength, toughness, low temperature resistance and corrosion resistance, and good welding performance. Commonly used hull structural steels include general-strength steel ( A , B , D , E ) steel plates specified in GB712 , high-strength steel ( AH32 , DH32 , EH32 , AH36 , DH36 , EH36 ) steel plates; high-quality carbon steel plates for ships specified in GB5312 Plain steel ( CIO , C20 ) Steel pipes ; Class A and B steel ball flat steels for shipbuilding specified in GB9945 .
Wide and thick steel plates for shipbuilding include general strength ship plates ( A-E) , high-strength ship plates ( AH32-EH40) , ultra-high-strength ship plate steels ( AH42-FH69) , marine boiler plates, and Z - direction steel plates for shipbuilding and offshore platforms. steel plate etc. The main technology of ship plate steel production is developing from high-carbon single element, low-carbon multi-element, to microalloying and composite microalloying; from low-strength grade to high-strength grade and ultra-high-strength grade. At present, the strength of ship plate steel can generally reach 450~980MPa . Marine rigid materials are one of the main materials used in ships. The actual cost of steel materials in ship construction accounts for about 20% of the ship cost . Therefore, reducing the consumption of marine steel will undoubtedly have a decisive impact on improving the economic benefits of shipbuilding.
1. Development status of international marine steel
Over the years, the world's shipbuilding powers have done a lot of work in the research and development of marine steel. As early as the 1950s , the United States began to use high-strength low-alloy steels such as HY-80 , HY-1OO , and HY-130 in the field of shipbuilding, and now they have been generally replaced by HSLA-80 and HSLA-100 series high-strength steels. Japanese researchers have developed a series of high-strength hull structural steels, such as modulated high-strength steel, martensitic effective steel and dual - phase strengthened steel. more than double. The "Triumph" class nuclear submarine built by France in October 1989 used HLE S100 steel with a yield strength of 980MPa . Russia has developed AB series ship steels with strength ranging from 390-1175MPa . Since the founding of the People's Republic of China, our country has successfully developed 390 , 440 , 590 , 785MPa high-strength ship steel series.
Marine steel is constantly developing. British naval shipbuilding steel has developed from mild steel to silicon-manganese steel in normalized state, carbon-manganese-molybdenum steel in normalized and tempered state, and then developed to fully quenched and tempered state. carbon-silicon-molybdenum steel. When producing high-strength steel, thermomechanical control methods (TMCP) are usually used . The use of TMCP technology can effectively improve the brittle cracking of welds. Due to the low carbon content and good welding performance of TMCP ship plates, the preheating process of shipbuilding and marine engineering construction can be exempted, welding costs can be reduced, welding production efficiency can be improved, and social benefits can be achieved. And economic benefits are remarkable, the market prospect is broad.

Development Trend of my country's Ship Plate Steel
Ship plate steel has to bear complex dynamic loads during its service. During the construction and assembly of the ship, the structural parts will generate huge stress . Continuous sailing in harsh environments, at the same time, in consideration of resources and environmental protection, (continued to page 36 )
LNG receiving stations should be located on the entry and exit channels of the port area
In order to reduce the impact of navigation control measures on navigation efficiency, it is also conducive to the navigation and operation safety of LNG ships.

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